Factors Affecting Beer Quality During Storage – A Review

Abstract

Fermented beverages such as beer are known for their relatively long shelf life. However, the main factor limiting their shelf life is the qualitative changes that occur during storage. From the moment the beer is produced, its characteristics, such as taste, aroma, and colloidal stability undergo continuous change. The intensity of these changes depends on the type of beer, storage conditions, and length of storage. While some degree of ageing can have a positive influence on sensory characteristics of a beer, beer stalling is seen as a significant problem. As it is currently understood, beer ageing is mainly caused by the formation of stalling aldehydes. At the same time, compounds which bestow the beer its flavour, such as esters, terpenes, and iso-α-acids undergo qualitative and quantitative changes. As a result, aroma discriminants such as freshness, fruitiness or florality are often lost over time. In their place, aromas described as ribes, cardboard, bread-like, honey-like or sherry-like appear. The article aims to present the changes in beer sensorial, physicochemical, and microbiological characteristics during storage and the factors that affect beer quality during ageing The article also describes the variables which according to the current literature, may alter the flavour stability of a beer.

Full text

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 1
Vol. XXVIII (2024), no. 1
FACTORS AFFECTING BEER QUALITY DURING STORAGE – A REVIEW
- Review -
Krystian Klimczak*, Monika Cioch-Skoneczny, Aleksander Poreda
Department of Fermentation Technology and Microbiology, University of Agriculture in
Kraków, ul. Balicka 122, 30-149 Kraków, Poland
Abstract: Fermented beverages such as beer are known for their relatively long shelf life. However, the main factor
limiting their shelf life is the qualitative changes that occur during storage. From the moment the beer is produced,
its characteristics, such as taste, aroma, and colloidal stability undergo continuous change. The intensity of these
changes depends on the type of beer, storage conditions, and length of storage. While some degree of ageing can have
a positive influence on sensory characteristics of a beer, beer stalling is seen as a significant problem. As it is currently
understood, beer ageing is mainly caused by the formation of stalling aldehydes. At the same time, compounds which
bestow the beer its flavour, such as esters, terpenes, and iso-α-acids undergo qualitative and quantitative changes. As
a result, aroma discriminants such as freshness, fruitiness or florality are often lost over time. In their place, aromas
described as ribes, cardboard, bread-like, honey-like or sherry-like appear. The article aims to present the changes in
beer sensorial, physicochemical, and microbiological characteristics during storage and the factors that affect beer
quality during ageing The article also describes the variables which according to the current literature, may alter the
flavour stability of a beer.
Keywords: beer, staling, stability
INTRODUCTION
Beer is one of the oldest, and most widespread
alcoholic beverage in the world. In many regions,
its production and consumption are of great
economic, cultural, and social importance. Beer’s
position on the market has led producers to
continually seek out new products to gain
consumer interest. In recent years, many not
widely known beer styles and types have gained
popularity. Brewers can use special malts,
different varieties of hops, the addition of fruit and
other botanicals (including functional additives),
and different strains and species of yeast to interest
the consumer. Traditionally, beer contains 3-6%
ABV (alcohol by volume), but beers with much
higher as well as lower alcohol content can be
found on the market (Marcos et al., 2021). It is the
latter that has been gaining popularity in recent
years. This is related, among other things, to
growing health awareness of consumers. Thanks
to this trend, alcohol-free, reduced, and low-
alcoholic beers have emerged in recent years.
Unfortunately, the changes in the brewing market
Received: 03.02.2024
Accepted in revised form: 18.05.2024
have outpaced legislative issues.
So far, the naming of beers based on their alcohol
content have not been consistently distinguished
in individual countries. The scale of this problem
can be illustrated, for example, by the differences
between the legal frameworks of the United
Kingdom and Finland. While in the UK, alcohol-
free beer must contain less than 0.05% ABV, in
the case of Finland such beers can have up to 2.8%
ABV (Okaru & Lachenmeier, 2022).
Nowadays, food safety is not simply an expected
issue – it is a requirement from consumers and
legislators (Lipp, 2021). In that respect, beer is
widely regarded as a microbiologically stable
product. Factors such as very low oxygen content,
low pH, the presence of hop-derived compounds
(such as iso-α-acids), carbon dioxide and alcohol,
along with the absence of nutrients significantly
limit the growth of unfavourable microflora in the
product (Oldham & Held, 2023). The processes to
which beer is often subjected, such as sterilization
and pasteurization are also important. This does
not mean that unfavourable microflora can’t
develop in all types of a beer – but the survival of
food-borne pathogens under these conditions is
made much more difficult (Menz et al., 2011).
Series E: Food technology
ACTA
UNIVERSITATIS
CIBINIENSIS
Series E: Food technology
ACTA
UNIVERSITATIS
CIBINIENSIS
Series E: Food technology
ACTA
UNIVERSITATIS
CIBINIENSIS
Series E: Food technology
ACTA
UNIVERSITATIS
CIBINIENSIS
Series E: Food technology
ACTA
UNIVERSITATIS
CIBINIENSIS
DOI : 10.2478/aucft-2024-0001
* Corresponding author.
E-Mail address: krystian.klimczak.sd@student.urk.edu.pl

Klimczak et al., Factors affecting beer quality during storage – A review 2
For most standard beers on the market, microbial
contamination is a relatively unlikely event.
However, it should be borne in mind that the
situation may be different for reduced, or non-
alcoholic beers. The absence of one of the
microbial growth hurdles may make them more
susceptible to microbial contamination. At the
same time, among other factors, when fruit
additives are used, nutrients are supplied to the
finished product that can be utilized by
microorganisms (Moreno et al., 2022).
However, the transformations that affect all beers
are the qualitative changes that occur during
storage. From the moment beer is produced, it
undergoes a continuous process of changes in,
among other things, aroma, flavour and colloidal
stability. These changes can vary in intensity
depending on the type of beer, storage conditions
and length of storage. Understanding the factors
that drive these changes can enable brewers to
prolong the flavour stability of beer. While some
styles can benefit from prolonged maturation and
storage (such as porters and stouts), many of the
more common styles on the market (such as lagers
or IPAs) tend to deteriorate with prolonged
storage. Finding factors that can extend the
stability of a beer will therefore be of great benefit
to both brewers and consumers. It cannot be
overlooked that food waste is currently a crucial
issue. In 2021, more than 58 million tonnes of food
waste were generated in the European Union alone
(Food Waste and Food Waste Prevention -
Estimates, 2023). Beer ageing is a significant
problem because it adversely affects consumer
perception of the product, hurts the brand image,
and can contribute to resource wastage. The aim
of this paper is to review the physicochemical
changes occurring during beer storage. In
addition, an attempt will be made to describe the
factors influencing stability of the product. This
information can be used by brewers to understand
factors driving beer flavour deterioration.
CHANGES IN BEER DURING THE STORAGE
Beer is an extremely complex mixture of chemical
compounds derived from the raw materials used,
those formed during wort production and by-
products of yeast metabolism. Although it consists
almost solely of water, alcohol, and residual
extract, there are hundreds of other of substances
in its composition. These substances are present in
much lower concentrations than those listed, but
they have a key influence on the sensory
characteristics of the beverage produced (Steiner
et al., 2010). These compounds are often not in
chemical equilibrium or are relatively unstable.
For this reason, spontaneous reactions will occur
during storage which mainly change the
organoleptic characteristics of the beer. The
transformations occurring during beer storage will
be discussed below.
Changes in taste and aroma
Some of the most noticeable changes that occur
during the storage of beer are changes in its
sensory characteristics. During storage, aroma
discriminants such as freshness, fruitiness or
florality are often lost over time. In their place,
aromas described as ribes, cardboard, bread-like,
honey-like or sherry-like appear (Boccorh &
Paterson, 2002). It is important to note that the
sensory changes depend on the type of beer,
whether it is a lager or an ale. This is related to
their initial sensory characteristics, thus among
others - volatile compounds composition. In a
study by Schubert et al. (2022) fresh ales
contained higher concentrations of aldehydes
(Schubert et al., 2022).
For many years, researchers have tried to
determine what phenomena are behind the
appearance of these undesirable sensory changes.
Current literature indicates that the ageing process
of beer appears to be significantly related to
aldehydes produced in Maillard reactions, Stecker
degradation, and lipid oxidation (Baert et al.,
2012). Some of the more important compounds
responsible for beer flavour deterioration are
given in Table 1. Although these compounds are
often found below their sensory threshold, the
concentration above or below sensory threshold
does not mean the compound will affect beers’
sensory characteristics. Synergistic, antagonistic
or additive effects can alter sensory thresholds of
compounds (Gernat et al., 2020; Stevens, 1996).
Dark beers and beers with a high alcohol content
may be especially prone to the formation of
elevated 2-furfuryl ethyl ether concentrations.
This compound, in amounts exceeding the sensory
threshold, can impart a solvent-like, stale flavour
(de Almeida et al., 2012). Low pH may promote
the appearance of this compound (Vanderhaegen
et al., 2004).

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 3
Vol. XXVIII (2024), no. 1
Table 1. Selected compounds associated with beer staling(Aguiar et al., 2022; Gijs et al., 2000; Saison, De
Schutter, Uyttenhove, et al., 2009; Soares da Costa et al., 2004; Wietstock, 2017)
Compound
Aroma
Sensory
threshold [ppb]
Concentration in
fresh beer [ppb]
Concentration in
aged beer [ppb]
Strecker aldehydes
2-methylpropanal
Grainy, varnish, fruity
86
17.2a,b
215.8a
57.2b
2-methylbutanal
Almond, apple-like,
malty
45
6.5a,b
3.2-5-6d
3.4g
21.2a
10b
6.5-8.1d
4.6g
3-methylbutanal
Malty, cherry,
almond, chocolade
56
16.6a,b
7.1-12d
7.2g
50.0a
25.3b
9.7-14.9d
7.9g
phenylacetaldehyde
Hyacinth, flowery,
roses
105
24.7a,b
5.3-10.4d
19.2g
51.6a
31.9b
7-15.4d
29.5g
benzaldehyde
Almond, cherry stone
515
1.4a,b
0.9-1.1d
5.7g
1.5a
1.7b
1.1-1.9d
5.1g
methional
Cooked potatoes,
worty
4.2
4.2a,b
11-41d
15.4a
8.5b
26-66d
Fatty acid oxidation
hexanal
Bitter, winey
88
0.8 a,b
1.2a
0.7b
trans-2-nonenal
Cardboard, papery,
cucumber
0.03
0.033 a,b
0.08g
0.090a
0.046b
0.10g
Maillard reaction
2-Furfural
Caramel, bready,
cooked meat
15,157
5.1a,b
2.5-5.7d
48.1g
221.4a
17.5b
32.4-47.8d
258.5g
5-hydroxymethylfurfural
Bready, caramel
35,784
1800f
4230f
acetylfuran
Nutty, almond, burnt
513
3.4-3.6d
8.4g
3.6-4d
14g
furfuryl ethyl ether
Solvent
11
2.7g
16.1g
γ-nonalactone
Coconut, vanilla,
glue, rancid
607
15.1-16d
20-22.3d
Carotenoid degradation
β-damascenone
Coconut, tobacco, red
fruits
203
6-25c
1.0g
14-210c
2.0g
Polysulfides
dimethyl trisulfide
Onion, rotting fruit,
red cabbage, sulfury
0.027
0.006-0.019e
0.098-0.179e
The same superscripts in table cells refer to data obtained from the same study
a – study by (Schubert et al., 2022) fresh blonde ale; beer after 24 weeks at room temperature,
b – study by (Schubert et al., 2022) fresh blonde ale; beer after 24 weeks at 4°C,
c – study by (Chevance et al., 2002), fresh; artificially aged beer (40°C for 5 days),
d – study by (Herrmann et al., 2010), fresh; artificially aged beer (1 day shaking, 4 days at 40°C),
e – study by (Gijs et al., 2000), fresh; force aged beer (40°C for 5 days),
f – study by (Bravo et al., 2001), beer kept at 0°C; beer kept at 28°C,
g – study by (Vanderhaegen et al., 2003), fresh; beer stored for 6 months at 20°C

Klimczak et al., Factors affecting beer quality during storage – A review 4
During storage, levels of dimethyl sulfide (DMS)
can also elevate (Baldus & Methner, 2019). In
addition to the appearance of compounds with
unfavourable sensory properties, those found in
beer undergo transformation and/or degradation.
Terpenes found in beer are susceptible to
oxidation processes (Almeida et al., 2015).
Myrcene is known to be absorbed on cap crown
liners of a bottles (Kemp et al., 2021). It can also
be adsorbed on the yeast walls if yeast cells are
present in beer (Haslbeck et al., 2017). Esters
found above their chemical equilibrium will
hydrolyse. In turn, the esterification of ethanol
with organic acids present in the beer will occur
simultaneously. In particular, for some highly
hopped beers this can have a detrimental effect on
their aroma. In contrast, the concentration of
terpene alcohols appears to be relatively stable
during storage (Preedy, 2009; Schubert et al.,
2022). The instability of esters and terpenes, with
concurrent relatively high stability of terpene
alcohols is confirmed by (Guan et al., 2019). In the
case of polyfunctional thiols (which are currently
suspected to be an important determinants of the
tropical aroma of some beers), their concentration
appears to depend on storage time. In a study by
Tran et al. (2015), the content of these compounds
increased up to 3 months of storage, while after 1
year of storage, the beers lost most of the
evaluated polyfunctional thiols (Tran et al., 2015).
Beer bitterness also undergoes quantitative and
qualitative changes during storage. This is
primarily related to the transformation of hop
acids (α-, β- and iso-α-acids), which undergo
oxidative degradation during beer storage. During
the boiling of wort, α-acids from hops are
isomerized to iso and trans-forms. Typically, the
ratio of cis:trans-izo-α-acids is 70:30%. Whereas
iso-forms are mostly stable, trans-forms are far
more susceptible to degradation (Preedy, 2009;
Stewart et al., 2017; Titus et al., 2021). The
transformations of trans-iso-α-acids are largely
responsible for the quantitative and qualitative
declines in bitterness during beer storage (Cooman
et al., 2000). Intelmann et al. (2011) report that the
proton-catalysed cyclization of these compounds
produces conglomerates with harsh and lingering
bitterness (Intelmann et al., 2011). In beers
subjected to dry hopping, a significant part of their
bitterness may be derived from humulinones
extracted from hops (Parkin & Shellhammer,
2017). Ferreira and Colin (2021) report of a
relatively high instability of humulinones in dry-
hopped Belgian beer. In the author’s study, after a
2-year storage period at 20°C, a 25% decrease in
iso-α-acids content was observed, but the losses of
humulinones amounted to 91% (Ferreira & Collin,
2021). Alpha acids are also susceptible to
photodegradation (range of light λ= 350-500 nm),
resulting in a development of so-called sunstruck
flavour caused by the formation of 3-methyl-2-
butene-1-thiol (MBT). Due to the very low
sensory threshold of this compound, this aroma is
formed with a minimal loss of iso-α-acids
(Caballero et al., 2012; De Keukeleire et al.,
2008).
Physicochemical changes
Other parameters of beer can also undergo
changes during the storage. The most visible
change is the colour of beer, which gets darker.
The degree of colour change depends, among
other things, on factors such as pH, redox capacity,
temperature, and oxygen availability in the beer
matrix (Savel et al., 2010). The latter two are
likely the main causes of polyphenol oxidation,
which leads to the formation of compounds that
give the beer a deeper colour. Polyphenols
contribute to beer’s bitterness, colour, body, and
astringency (Oladokun et al., 2016; Preedy, 2009).
Structural rearrangements of flavan-3-ol
monomers can result in brown-yellowish
compounds. (+)-Catechin is suspected to be an
important precursor of these reactions. Another
potential cause are the coloured molecules derived
mainly from the Maillard reactions (Callemien &
Collin, 2007, 2009). The initial products of the
Maillard reactions have no colour, but as the
reactions proceed further, they result in larger
molecules, which begin to bestow the colour
(Bamforth & Lewis, 2007; Nooshkam et al.,
2019). Dark beers and beers with a higher alcohol
content show a higher levels of Maillard reactions
products (Vanderhaegen et al., 2007). This may be
related to the higher Free Amino Nitrogen (FAN),
and polyphenol content of such beers (Brey et al.,
2002; Cooper et al., 1998; Rivero et al., 2005;
Younis & Stewart, 1999). In addition, according
to the current knowledge, polyphenols are
responsible for the formation of chill and
permanent haze. Probably as a result of oxidative
and acid-catalysed polymerization, polyphenol
particles bind into larger clusters. Due to the
interactions with proteins, a haze may be formed
(Habschied et al., 2021). A summary of changes is
given in a Table 2.

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 5
Vol. XXVIII (2024), no. 1
Table 2. Summary of changes occurring during storage period
Type of changes
Process
References
Changes
affecting taste
and aroma
Maillard reactions, strecker
degradation, lipid oxidation,
carbohydrate degradation
(Baert et al., 2012; Bravo et al., 2008; Dale et al.,
1977; Gibson et al., 2018)
Increase in DMS levels
(Baldus & Methner, 2019; Grigsby & Palamand,
1977)
Terpene oxidation and/or adsorption
onto cap crown liners or yeasts
(Almeida et al., 2015; Guan et al., 2019; Haslbeck et
al., 2017; Kemp et al., 2021)
Changes in polyfunctional thiol
content and composition
(Cordente et al., 2015; Nizet et al., 2014; Tran et al.,
2015)
Hydrolysis of esters occurring above
chemical equilibrium, and subsequent
formation of ethyl esters
(Kemp et al., 2021; Preedy, 2009; Rettberg et al.,
2020)
Degradation of iso-α-acids (mainly
trans-iso-α-acids)
(Ferreira & Collin, 2021; Intelmann et al., 2011)
Losses of humulinones (in dry hopped
beers)
(Ferreira & Collin, 2021; Gahr et al., 2020)
Iso-α-acid photooxidation
(Caballero et al., 2012; De Keukeleire et al., 2008)
The concentration of terpene alcohols
can fluctuate depending on the
compound
(Guan et al., 2019; Schubert et al., 2022)
Physicochemical
changes
Haze formation
(Habschied et al., 2021; Wang & Ye, 2021)
Darkening of a beer
(Bamforth & Lewis, 2007; Callemien & Collin, 2007,
2009)
Growth of microflora
As mentioned previously, beer is regarded as
intrinsically microbiologically safe beverage. Its
microbiological safety can be enhanced further by
treatments such as pasteurization and sterilization
(Hammond et al., 1999). The fact of
microbiological safety of beer is attributed in part
to the significant antimicrobial activity of hop
constituents and is mainly observed against gram
(+) bacteria. The individual components of hops
have different antimicrobial activity, where β-
acids show greater activity than α-acids
(Srinivasan et al., 2004). However, β-acids pass
into beer only in trace amounts (Cortese et al.,
2020). Important food pathogens such as Listeria
monocytogenes or Staphylococcus aureus do not
show growth even in non-alcoholic beer. This is
related to the hop resins which significantly inhibit
the growth of gram (+) bacteria. Gram (-)
foodborne pathogens such as Escherichia coli or
Salmonella typhi also do not show growth in beer,
although, in the authors’ study, S. typhi could
survive for more than 30 days in a beer with
medium ABV levels (2.5-3.6 %) when stored at
4°C (Menz et al., 2011). Most authors confirm that
foodborne pathogens are unable to grow in beers
of typical alcohol content (Kim et al., 2014; Menz,
Vriesekoop, et al., 2010; Munford et al., 2017).
However, these bacteria can survive in such an
environment or remain in spore form by which
they are relatively often detected in beers found on
the market (Jeon et al., 2015; López et al., 2021;
Munford et al., 2017). However, attention should
be paid to emerging bacterial strains that show the
ability to grow in beer. An example of a
pathogenic strain showing the ability to grow in
beer is the recently discovered Bacillus cereus
strain 3012 (Wang et al., 2017).
Although there seems to be no direct threat from
pathogenic bacteria, microorganisms which are
able to grow in beer can significantly alter the
sensory qualities and physicochemical parameters
of the beer. Bacterial infections can cause various
types of turbidity, development of films on the
surface of the beverage, foreign aromas and
aftertastes. Examples of such microorganisms
include but are not limited to, lactic acid bacteria,
Pediococcus damnosus, Pectinatus
cerevisiiphilus, Megasphaera cerevisiae and
Staphylococcus xylosus (Menz, Andrighetto, et
al., 2010; Rodríguez-Saavedra et al., 2020;
Sakamoto & Konings, 2003; Yu et al., 2019).
A significant threat to beer quality is the
development of wild yeasts (non-Saccharomyces
species). In the craft beers studied by Lopez et al.
(2021), wild yeasts were detected in 100% of
samples of beer below 5% ABV (López et al.,
2021). Candida pelliculosa yeast species can be
found on production surfaces in breweries. This
yeast can grow in beer and form a biofilm (Timke
et al., 2008). An important threat is S. cerevisiae
var. diastaticus, which shows the ability to
degrade sugars not fermented by brewer's yeast. In
the beers studied by Štulíková et al. (2021), storing
beer infected with this yeast for 14 weeks at 23°C
resulted in a decrease in extract content, with an

Klimczak et al., Factors affecting beer quality during storage – A review 6
increase in alcohol content and in carbonation
(almost twofold increase of CO2 content). When
beverages were stored at a lower temperature
(8°C), a much lower severity of these defects was
observed. In extreme cases, infection with these
yeasts can cause gushing to occur (Krogerus &
Gibson, 2020; Štulíková et al., 2021). Yeasts of
the genus Dekkera - D. anomala, D. bruxellensis
and B. custersianus are also known to grow in beer
(Shimotsu et al., 2015).
As alcohol is one of the microbial hurdles present
in beer, beers containing low levels of ethanol, or
no-alcohol beers are more vulnerable to various
types of microbial contamination. Menz et al.
(2011) found that E. coli O157:H7 and Salmonella
typhimurium can grow in non-alcoholic beer.
However, the growth was arrested when the pH of
the beer was lowered from 4.3 to 4.0 (Menz et al.,
2011). Similar results regarding the importance of
pH levels were obtained by Munford et al. (2017).
The authors did not observe the growth of
sporeforming bacteria in non-alcoholic beer,
which was attributed to the low pH of these beers
(below 4.5) (Munford et al., 2017). The relatively
low susceptibility of alcohol-reduced beers to
LAB infections can be inferred from a study by
Sohrabvandi et al. (2010), where the authors used
the addition of probiotic cultures to low and non-
alcoholic beers. A very large decrease in the
viability of the cultures was observed. The authors
suggest that beer is not a suitable medium for such
cultures (Sohrabvandi et al., 2010). Nevertheless,
the important role of alcohol in ensuring the
microbiological safety of beer must be kept in
mind. Quain (2021), based on the measurement of
absorbance at λ=660 nm, determined that, in
draught beers, the growth of microorganisms in
non-alcoholic (≤ 0.05% ABV) and low-alcohol (≤
1.2% ABV) beers was 2-5 times higher than in
control beers (4.5% ABV). The degree of
absorbance rise correlated with the content of
fermentable sugars in these beers (Quain, 2021).
L’Anthoën and Ingledew (1996) reports of
increased temperature resistance of
microorganisms in reduced alcohol beer (0.5%),
compared to regular beer (5%). In the authors’
study, the bacteria Pediococcus acidilactici,
Lactobacillus delbrueckii, E. coli O157:H7 and S.
typhimurium showed 3-17x higher temperature
resistance in non-alcoholic beer (L’Anthoën &
Ingledew, 1996). If arrested fermentation methods
are used to produce alcohol-reduced beer, a
significant number of fermentable sugars can
remain in the product which may increase the
susceptibility of such beverage to infection
(Sohrabvandi et al., 2010).
FACTORS AFFECTING FLAVOUR STABILITY
In recent decades, brewing science has made
considerable progress in understanding the factors
that affect stability of a product. However, due to
the vastness of the physicochemical reactions
occurring during ageing and the number of
interactions between beer components, many
questions remain unanswered. Based on the
current state of knowledge, it can be concluded
that almost every factor occurring during
production process has an impact on the final
stability of the product. In the following
paragraphs, literature reports on factors that can
affect the storage stability of the final product will
be presented. A summary of the changes which
will be presented below is given in Figure 1.
Figure 1. Overview of factors promoting beer flavour stability.

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 7
Vol. XXVIII (2024), no. 1
Raw materials
The selection of raw materials for the production
of wort is a base for all brewing recipes. As it has
a very significant impact on the final
characteristics of the product, it naturally will
affect the stability of the beer during storage.
Guido et al. (2007) point to the important role of
malt-derived polyphenols in improving beer
flavour stability. Highly polymerized phenolic
compounds and/or insoluble bound polyphenols
have an important function in reducing oxidation
reactions during malting and mashing stages. In
contrast, the fraction remaining in the wort after
wort production seems to have no such effect, and
even function as pro-oxidant (Guido et al., 2007).
However, Mikyška et al. (2002) report that malt
polyphenols can have a positive effect on a beer's
stability (Mikyška et al., 2002).
An important issue affecting the final sensory and
physicochemical characteristics of the beer, along
with the fermentation yield, is the Free Amino
Nitrogen (FAN) content. For a standard wort with
an extract of 10-12°P, it is assumed that the FAN
content should be around 130 mg/L. Below this
value, yeast growth is nitrogen-dependent (Hill &
Stewart, 2019). In some cases, it is possible to not
reach the required FAN levels (for example, when
large proportions of unmalted adjuncts are used).
Some breweries may use the so-called protein
rests, which involve holding the mash at 45 - 50°C
to increase the FAN level due to the activity of
endogenous malt proteinases (Bamforth, 2009;
Farber & Barth, 2019). However, excessive
increases in FAN concentration can have adverse
effects on the storage stability of the beer. High
levels of FAN are associated with significant
levels of stalling aldehydes (Maia et al., 2023).
Lehnhardt et al. (2020) reports of elevated
Strecker aldehydes content caused by high soluble
nitrogen levels (Lehnhardt et al., 2020). For this
reason, the use of unmalted adjuncts may be
beneficial to reduce FAN content and increase
flavour stability, by reducing the amount of
Maillard reaction precursors (Kunz et al., 2011).
However, too high proportion of unmalted
adjuncts can provide too little FAN and low
amounts of soluble proteins which results in
emptier-bodied drink. It can also have an adverse
effect on foam characteristics (Bogdan &
Kordialik-Bogacka, 2017).
The currently available literature points out that
various types of malts and unmalted raw materials
can affect the storage stability of beer differently.
According to Hellwig & Hentle (2020) the type of
malt (light, dark, caramel, colour) is not a
determinant of the content of Maillard reaction
precursors (Hellwig & Henle, 2020). However,
Shopska et al. (2021) report that malts subjected
to higher heat treatment (which are characterized
by darker colour) have a higher content of
Maillard compounds with antioxidant activities,
and thus higher antioxidant activity (Shopska et
al., 2021). The higher antioxidant activity of beers
with coloured malts is also reported by the
(Liguori et al., 2021). In a study by Maia et al.
(2023) addition of unmalted rice or maize at 50%
of grist allowed to reduce total metal ion content,
colour, thiobarbituric cid index, and stalling
aldehyde content (Maia et al., 2023). Tsuji and
Mizuno (2010) report fewer stalling compounds in
beer made from raw materials other than malt
(Tsuji & Mizuno, 2010). The use of LOX-less
(lipoxygenase-less) malt may allow to obtain a
wort with a lower nonenal potential. LOX-less
malt lacks genes encoding lipoxygenase enzyme
responsible for catalysing oxygenation of some
unsaturated fatty acids. In the finished forced-aged
beers obtained during the study, significantly
lower concentrations of trans-2-nonenal and γ-
nonlactone were determined than in the control
sample brewed with traditional malt. In addition,
the beers were characterized by significantly
better results of sensory evaluation in the
‘freshness’ category (Yu et al., 2014).
Additionally, adequate malting conditions can
significantly reduce the nonenal potential of a malt
(Guido et al., 2005)
As well as providing aroma and flavour
compounds, hops are also an important source of
polyphenols in beer production. It can provide up
to 20-30% of these compounds to the wort, while
the rest comes from malt (Mikyška et al., 2011).
Current literature indicates that hop-derived
polyphenols can have a positive effect on the
storage stability of beer. This is confirmed by
Mikyška et al. (2011), where the authors used
different doses of hops (25-50-100%) in the
production process. Higher doses of this raw
material significantly reduced the formation of
undesirable carbonyl compounds. The authors
attribute this partly to the significant content of
antioxidants in hops (Mikyška et al., 2011). The
important role of hops in its raw form in terms of
beer storage stability is also confirmed by the
authors’ previous research. Using the pelleted
hops instead of hop CO2 extract significantly
increased the beverage storage stability (Mikyška
et al., 2002). Drexler et al. (2010) reports that hops
harvested at a later date of technological
suitability (21 day difference between the harvest
date) may provide better aroma stability during
storage in dry-hopped beers. However, this
improvement was only observed for the first 45
days of storage, after which the differences

Klimczak et al., Factors affecting beer quality during storage – A review 8
between the beers subsided (Drexler, 2010). The
positive effect of hops on oxidative stability was
also reported by Hrabia et al. (2022). Beers
subjected to dry hopping showed a greater lag time
(the time after which free radical reactions initiate)
(Hrabia et al., 2022). Mikyška et al. (2022) report
that aromatic hops, with a high polyphenol to α-
acid ratio, can reduce sensory ageing to a greater
extent than bittering hops (Mikyška et al., 2022).
A similar effect was not observed by Jaskula et al.
(2007), where no significant differences in
bitterness stability were observed between hop
types when early kettle hopping was used.
Similarly, no effect of dry hopping on bitterness
stability was observed. However, late hopping
during the whirlpool phase resulted in the
stabilization of iso-α-acids. Almost full
stabilization of cis isomers was observed, with a
partial stabilization of trans isomers. In terms of
bitterness stability, the use of a pre-isomerized
extract of tetrahydroiso-α-acids gave the best
results, where the authors observed no change in
their concentration even when prolonged forced
ageing was used (Jaskula et al., 2007). Hops,
particularly those sprayed with copper-based
fungicides, can be a significant source of Cu ions.
In addition, they can introduce significant
amounts of manganese ions. In the authors’ study,
a 296-511% increase in Mn content was observed
compared to the non-dry-hopped sample. In the
case of Cu ions, it was 105% (Chrisfield et al.,
2020). The significant content of metal ions in
hops is also reported by Wietstock et al. (2015).
Conditions of the fermentation process
The state of the yeast and the conditions under
which fermentation takes place are important
factors in determining the storage stability of the
beer. Kaneda et al. (1992) report that lower
dissolved oxygen concentrations, higher yeast
pitching rate, and clearer wort lead to higher
sulfide production, which in the authors’ study
translated into higher beer storage stability. The
strain of the yeast itself appears to also be of
significant importance, which is confirmed by the
results of the aforementioned study (Kaneda et al.,
1992). These reports are supported by a study by
Jenkins et al. (2021), where the authors studied 11
S. cerevisiae strains. The authors indicate that the
application of yeast strain with high resistance to
multiple oxidative stresses correlates with the
production of beer with higher oxidative stability
(Jenkins et al., 2021). Yeast strains which produce
higher concentrations of sulfide may allow to
obtain beers with higher stability. Sulfide
production is probably strain-dependent (Saison et
al., 2009). On the other hand, Murmann et al.
(2023) report that higher FAN utilization may be
a more important factor than sulfide production. In
the authors’ study, beer obtained using a strain that
produced higher levels of sulfide scored lower in
the general evaluation of sensory characteristics
after storage (16 weeks at 35°C) than the beer
obtained with a strain which utilized higher
amounts of FAN. Beer produced with a high-
sulfide-producing strain of S. cerevisiae had more
fruity/vinous characteristics, which authors
attribute to Maillard reactions (Murmann et al.,
2023). Yeast can also complex Fe2+, Mn2+, and
Cu2+ ions. However, in the authors study, the
content of these ions in the wort increased towards
the end of fermentation, suggesting yeast autolysis
or secretion of these ions by yeast cells (Mochaba
et al., 1996). Guido (2004) reports that pitching
yeast with higher viability can result in higher
sensory stability.
Metal Ions
Beer can also be seen as an aqueous solution of
organic and inorganic substances. Ions of the latter
are the important components of such solution.
They are transferred with the water used in the
production of beer, derived from raw materials, or
equipment, or are intentionally added during the
production process. Some of the ions (Ca2+, Mg2+,
Na+, K+, Mn2+, Zn2+) in the adequate levels are
required for the correct course of mashing and
fermentation, and/or directly affect the sensory
characteristics of the beer. On the other hand, the
presence of other ions, especially in excessive
levels can cause sensory defects (Fe2+, Fe3+ ions -
metallic taste above 1 mg/L). However, it has long
been known that transition metal ions are largely
responsible for the formation of stalling aromas in
beer. In the presence of Fe and Cu ions, stable
oxygen molecules present in beer capture
electrons and form superoxide anions. In a series
of reactions reactive oxygen species are formed
(O2-, OOH•, H2O2, OH•) which react with the
organic compounds present in the beer. As a
result, sensory characteristics of a beer can be
altered (Preedy, 2009). In the case of Fe,
concentrations of 50 ppb are sufficient to affect the
sensory characteristics of the finished product.
Zufall and Tyrell (2008) report that Mn ions can
also act in a pro-oxidative manner. Manganese
ions are required for the proper yeast growth. To
determine the effect of Cu2+, Fe2+ and Mn2+ ions,
the authors added specific amounts of these ions
during the beer production process. A significant
decrease in Fe ions was observed during
fermentation. In contrast, Cu content decreased
during boiling and trub removal. The addition of
Mn to the wort correlated with a higher Mn

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 9
Vol. XXVIII (2024), no. 1
content in the beer. Accelerated spoilage was
observed in beers to which Mn was added, which
was manifested by the appearance of a sherry
aroma after 4 weeks of storage. The effect of Mn
ions was concluded to be detrimental to the
storage stability of the beer, but lower than that of
Cu and Fe ions (Zufall & Tyrell, 2008). According
to Jenkins et al. (2018), the addition of even 10
ppb of transition metals can affect the oxidative
stability of beer. In the authors' study, the addition
of Cu caused the greatest reduction in lag time
among assessed metals (Fe, Cu, Mn). The addition
of Fe caused a reduction in lag time and an
increase in T450 value (an indication of how much
staling may occur in a particular beer). In line with
the results obtained by Zufall and Tyrell (2008),
the addition of Mn generally resulted in the
greatest increase in T450 value. The effect of Mn
ions seems to be detrimental (Jenkins et al., 2018).
Application of selected metal chelators to the
mashing process can reduce the content of
transition metal ions. Mertens et al. (2021) report
that additives such as green tea extract, tannic acid
or pomegranate extract can reduce Fe content.
Interestingly, in the study, addition of
ethylenediaminetetraacetic acid (EDTA), which is
known as a potent chelator, counterintuitively
increased the Fe content of the resulting wort.
Authors also observed that acidification of wort
(from pH 6 to 5 using HCl) caused significantly
higher levels of Fe, Mn, and Zn in resulting wort
(230, 320 and 150%, respectively) (Mertens et al.,
2021). Transition metal ions can also be partially
removed by bitter resins derived from hops.
Wietstock et al. (2016) report that in a buffered
model system, hop acids showed the ability to
complex Cu2+, Fe2+ and Fe3+ ions. There was no
observed complexation of Ca2+, K+, Mg2+, Mn2+
and Zn2+. The ability to complex ions depended on
the pH of the medium and the acid tested (α-, iso-
α, β-acids) (Wietstock et al., 2016). Maillard
compounds and polyphenols can also exhibit
chelating properties for Fe ions (Mondaca‐
Navarro et al., 2017; Mussche & Pauw, 1999).
Antioxidants
In brewing, sulfide, especially when it is present
in excessive levels, is usually associated with
defects, as it bestows a beer with a fetid smell of
rotten eggs. Sulfide is a product of natural yeast
metabolism. Typically, the concentration of this
compound in beer is below 10 ppm, and higher
levels of sulfide are produced under low yeast
growth conditions (Lea & Piggott, 2003; Stewart
et al., 2017). On the other hand, sulfide is also an
important compound with the ability to prolong
the storage stability of a beer. For some time, it
was believed that sulfide action was related to the
binding of carbonyls via adduct formation.
However, it’s activity is probably linked to
antioxidant properties (Bushnell et al., 2003;
Kaneda et al., 1996). Lund et al. (2015) report that
protein-thiols could play secondary roles as
antioxidants, mainly by quenching 1-
hydroxyethyl radicals. However, theirs reactivity
is lower than that of sulfide. Authors report thiols
probably compete with hop-delivered bitter acids,
as those also react with 1-hydroxyethyl radicals
(Lund et al., 2015). The content of thiol groups is
strongly correlated with sulfide content and beer
oxidative stability. The content of thiol groups is
not correlated with protein content, suggesting
that these groups may be present in peptides and
smaller molecules (Lund & Andersen, 2011). The
lesser degree of thiol antioxidant reactivity
compared to bitter acids is confirmed by the study
of Andersen et al. (2017). In the study, authors
performed a forced ageing of pilsner beer (IBU 35,
4.6% ABV). Thiols were found to react with
around 9% of 1-hydroxyethyl radicals, while bitter
acids accounted for 88%. The authors noted that
the effect of polyphenols was not significant,
probably due to the low reaction rates and low
concentrations of these compounds in the beer
tested (Andersen et al., 2017).
The positive effects of polyphenols on the storage
stability of beer have been reported by many
authors. In a study by De Francesco et al. (2020)
the addition of phenolic-rich extracts significantly
improved colloidal stability, colour formation and
foam quality. It also increased flavour stability and
had a protective effect on beer quality (De
Francesco et al., 2020). The positive effect of
individual polyphenols or beer additives
containing high amounts of them, such as soybean
extract, dried red raspberries or green tea, among
others, on the storage stability of beer is reported
by many authors (Bamforth & Parsons, 1985;
Chen et al., 2023; Walters et al., 1997a; Yang et
al., 2023; Yin et al., 2021). These additives are
likely to increase the antioxidant activity of the
beer. Another raw material that may increase the
antioxidant activity of beer is spent hops (Jaskula-
Goiris et al., 2014). Hop antioxidants suppress the
formation of carbonyl compounds during the
storage (Mikyška et al., 2011). However, some
additives, such as olive leaves can harm the
colloidal stability of a beverage (Guglielmotti et
al., 2020). Although in the studies of the above-
mentioned authors, the addition of polyphenols, or
polyphenol-rich materials had a positive effect on
storage stability, not all sources confirm such
results. In the study by Walters et al. (1997) the
addition of catechins (+) and ferulic acid had no

Klimczak et al., Factors affecting beer quality during storage – A review 10
effect on the rate of formation of stalling
aldehydes (Walters et al., 1997b). The addition of
tannins may also reduce the development of a
sunstruck flavour (Munoz-Insa et al., 2015).
Technological operations
Pasteurization is a commonly used process in
industrial beer production. Current knowledge
indicates that this procedure can have a positive
effect on the storage stability of beer. In a study by
Lund et al. (2012), pasteurization increased the
storage stability of beer as determined by electron
spin resonance spectroscopy. In unpasteurized
beer, a faster rate of radical formation and greater
protein degradation were observed, probably due
to the enzymatic activity of yeast residues. The
authors suggest that higher protein content may
have a positive effect on the storage stability of
beer by binding prooxidative metals or by acting
as a catalyst for the removal of H2O2 formed
during oxidative reactions in beer (Lund et al.,
2012). The positive effect of pasteurization is also
reported by Hoff et al. (2013), where the authors
subjected unfiltered beer to accelerated ageing
(40°C, 41 days). The pasteurization process
negatively affected the volatile compound
composition of the beer, but after the storage
period studied, the differences between the
samples disappeared. During storage, pasteurized
beers gave a lower rate of radical formation
(determined using ESR spectroscopy). No
differences were observed in the content of pro-
oxidative metals (iron and copper) between the
beers (Hoff et al., 2013). The positive effect of
pasteurization on long-term storage stability is
also reported by Liu et al. (2018). The staling
grade of a fresh pasteurized beer was similar to
that of draft beer after 1 month of storage. The
ageing rate of pasteurized beer was slower than
that of fresh beer (Liu et al., 2014). However,
attention should be paid to the parameters of the
pasteurisation. Cao et al. (2011) studied the
deterioration of the beer sensory characteristics
during 6-month storage of samples subjected to
increasing PU (Pasteurization Units) – 2,8,14.
With increasing PU, an intensification of colour,
and a decrease in both polyphenol and ester
content were observed, with a concomitant
increase in undesirable compounds such as
acetaldehyde or DMS. The unfavourable effect of
higher PU values was also confirmed by sensory
analysis, where beers with higher PU were rated
worse than those with lower (Cao et al., 2011).
Another interesting way to extend the shelf life of
beer is the use of additives. The addition of
chitooligosaccharide can limit the growth of LAB.
In addition, these compounds can limit flavour
deterioration by inhibiting the formation of
stalling compounds, and increasing beer
antioxidant activity (Yang et al., 2017; Zhao et al.,
2016)
A refermentation in bottles – a procedure which is
often used to carbonate the beer in homebrewing,
and sometimes in the craft industry, can prolong
beverage stability (Štulíková et al., 2020). Ferreira
et al. (2019) report that the use of bottle
conditioning reduced the release of the trans-2-
nonenal from Schiff bases and resulted in the
release of terpenols and phenols which positively
affected the beers aroma. During the sensory
evaluation, the intensity of attributes usually
associated with beer ageing was judged to be
absent or low (Ferreira et al., 2019). This is
confirmed by the study by Saison et al. (2010),
where the effect of refermentation on aged beer
was studied; the yeast's have significant ability to
reduce the compounds responsible for stale aroma.
Cardboard, Ribes, Maillard and Madeira aromas
were greatly reduced as a result of this process. A
significant decrease in the content of (E)-2-
nonenal, Strecker aldehydes, 5-
hydroxymethylfurfural and diacetyl was observed
(Saison et al., 2010). The ability of yeast to reduce
stalling aromas/indicators has also been confirmed
by other authors (Carneiro et al., 2006; Wang et
al., 2006).
Storage temperature
Studies by many authors indicate that one of the
key factors in extending the shelf life of beer is to
store it at as low temperature as possible,
preferably refrigerated. Valentoni et al. (2022)
studied the effect of temperature on the storage of
refermented craft beer for 13 weeks. When stored
at 45°C, a reduction in IBU, a deepening of colour
and an increase in the concentration of the beer’s
ageing products: furan compounds and aldehydes
were observed. No differences were found
between the 22°C and 6°C samples, and these
beers showed less ageing signs. During sensory
analysis, beers stored at 45°C were characterized
by higher ripe fruit, cardboard, sweet and paint
flavour, while freshness was lower than in beers
stored at 22°C. This trend was evident up to 6°C,
at which temperature the beer had the highest
freshness (Valentoni et al., 2022). Walters et al.
(1997) report that when beer was stored at 40°C
for 156 days, a 71% loss of iso-α-acids was
observed, while temperatures of 0 and 20°C were
sufficient to arrest these losses (Walters et al.,
1997b). Heuberger et al. (2012) report that when
beer was stored at room temperature for 14 weeks,
greater changes in flavonoids, purine bases and
peptide concentrations were observed compared

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 11
Vol. XXVIII (2024), no. 1
to a sample stored at 4°C (Heuberger et al., 2012).
The lower temperature (4°C compared to 22.5°C)
also reduces the losses of esters (Heuberger et al.,
2016). For highly hopped ales, the lower storage
temperature (~3°C) helps to retain a higher
intensity of ‘citrous’, and ‘tropical’ qualities
compared to storage at a higher temperature
(20°C). When stored at a higher temperature, the
malty, sweet, and alcoholic qualities are brought
out (Kemp et al., 2021; Schubert et al., 2022).
Barnette & Shellhammer (2019) reports that the
loss of hoppy, fruity and citrousy characteristics is
not reflected in a loss of terpene alcohols
concentrations. The authors suggests the changes
in concentrations of other compounds, such as
polyfunctional thiols, aldehydes or lipid oxidation
products might be responsible for such changes
(Barnette & Shellhammer, 2019). In general,
research by many authors indicates that keeping
beer as cold as possible (~4°C) is the most
beneficial way to prolong its shelf life in terms of
aroma (He et al., 2012; Rodriguez-Bencomo et al.,
2012). A similarly beneficial effect of low
temperature on the stability of bitter substances is
reported by (Gahr et al., 2020).
Restricting oxygen exposure
As mentioned earlier, because oxygen takes a part
in radical reactions, its availability in the finished
beer has a detrimental effect on the stability of the
sensory characteristics. Wietstock et al. (2016)
report that oxygen significantly promotes the
formation of Stecker aldehydes during wort
production. In the authors’ study, the content of
Stecker aldehydes in beer during storage was
closely related to the available oxygen. The
application of oxygen barrier liner crown corks
significantly reduced the content of these
compounds. The additional use of 10 mg/L EDTA
effectively diminished the content of Stecker
aldehydes (Wietstock et al., 2016). The increase in
the content of 2-furaldehyde is oxygen dependent
(Carneiro et al., 2006). However, the content of
the some of the most prominent staling
compounds, such as trans-nonenal might be not
affected by oxygen levels. Lermusieau et al.
(1999) reports the major source of this compound
is the non-oxidative degradation of its precursors,
synthesized before fermentation (Lermusieau et
al., 1999). The negative effect of oxygen at most
stages of beer production and storage is confirmed
in the literature (Bamforth et al., 1993). The
oxygen content in the beer headspace before
pasteurization is correlated to the degree of
stalling that would take place. Hempel et al.
(2013), suggests the maximal oxygen content in
bottle headspace of 1% (Hempel et al., 2013).
However, the commonly used brewing procedure
of oxygenating the wort before yeast inoculation,
at a dose of 8 mg O2/L of wort, does not seem to
harm the storage stability of the beer, probably due
to the rapid utilization of oxygen by the yeast
(Depraetere et al., 2008). Kucharczyk and
Tuszyński (2017) reports of no changes in the
content of higher alcohols, esters and vicinal
diketones when the aeration in the range of 7-12
mg O2/L of wort was used.
Other factors
A characteristic feature of beer which significantly
limits the growth of unfavourable microflora is its
relatively low pH. The pH of most beers is in the
range of 3.4-4.8, with most beers having a pH in
the upper range (Preedy, 2009). The low pH of
3.3-3.9 is mostly found in sour beers (Ciosek et
al., 2020). Beers with a low pH may be more prone
to develop an oxidized taste during storage
(Kaneda et al., 1997). Guyot-Declerck et al.
(2005) report that ‘cardboard’ aroma (trans-2-
nonenal) and cooked vegetables (methional) are
less perceptible in beers with higher pH (4.6 vs
4.2). In contrast, coconut aroma (γ-nonalactone)
may be enhanced. François et al. (2006) report that
higher pH also reduces perceptible astringency in
beer (François et al., 2006). Higher pH slows
down the degradation rate of trans-iso-α-acids and
leads to lower furfural concentrations. However, it
can result in higher levels of Strecker aldehydes
when FAN content is significant. In addition, it
can increase the concentration of lipid oxidation
aldehydes (Jaskula-Goiris et al., 2011). Gijs et al.
(2002) report lower concentrations of β-
damascenone in higher pH beers, indicating that
the appearance of this compound is related to the
acid-hydrolysis of its precursors. The
concentration of methional, in contrast to the
Guyot-Declerck (2005) study, was higher at
higher pH (Gijs et al., 2002). Therefore, the effect
of pH level on the stability of sensory attributes is
ambiguous. However, based on the information
presented above, it is known that lower pH can
significantly reduce the risk of microflora
development, particularly in non-alcoholic beers,
or those with reduced alcohol content. Siebert
(2009) reports that the maximum intensity of
protein-polyphenol haze formation occurs at pH
~4 (Siebert, 2009).
Another important factor of beer stability is the
type of container used. Gagula et al. (2020) report
that when PET bottles are used, the composition
of volatile compounds in beer changes
significantly after only 1 month of storage. In the
case of glass bottles and cans, after 6 months of
storage, the authors estimated changes in volatile

Klimczak et al., Factors affecting beer quality during storage – A review 12
compounds to be minimal (Gagula et al., 2020).
Similarly, inadequate barrier properties of PET
bottles have been reported by (Lorencová et al.,
2019). Containers that do not transmit light <500
nm (brown containers, cans) prevent the formation
of sunstruck flavour caused by the formation of
MBT. Beers with higher colour are greatly more
resistant to development of this flavour.
Removing riboflavin from beer can also prevent
the formation of MBT (De Keukeleire et al., 2008;
Duyvis et al., 2000; Sakuma et al., 1991).
CONCLUSIONS
Currently available literature clearly shows that to
slow down detrimental sensory changes which
take place during beer ageing, a few actions can be
taken. To ensure the highest stability of a beer, it
should be kept at low, preferably refrigeration
temperatures. Additionally, several brewing
practices can significantly reduce the potential for
stalling during aging. Reducing oxygen exposure
during wort production, limiting prooxidative
metal ions content in brewing water, controlling
free amino content levels, and appropriate raw
materials can prolong beer stability.
LITERATURE
1. Aguiar, D., Pereira, A. C., & Marques, J. C. (2022). Assessment of Staling Aldehydes in Lager Beer
under Maritime Transport and Storage Conditions. Molecules, 27(3), 600.
https://doi.org/10.3390/molecules27030600
2. Almeida, N. E. C. de, Aguiar, I. de, & Cardoso, D. R. (2015). Mechanism of Hop-Derived Terpenes
Oxidation in Beer. Journal of the Brazilian Chemical Society. https://doi.org/10.5935/0103-
5053.20150231
3. Andersen, M. L., Gundermann, M., Danielsen, B. P., & Lund, M. N. (2017). Kinetic Models for the
Role of Protein Thiols during Oxidation in Beer. Journal of Agricultural and Food Chemistry, 65(49),
10820–10828. https://doi.org/10.1021/acs.jafc.7b05012
4. Baert, J. J., De Clippeleer, J., Hughes, P. S., De Cooman, L., & Aerts, G. (2012). On the Origin of Free
and Bound Staling Aldehydes in Beer. Journal of Agricultural and Food Chemistry, 60(46), 11449–
11472. https://doi.org/10.1021/jf303670z
5. Baldus, M., & Methner, F.-J. (2019). Effect of antioxidants on dimethyl sulphoxide reduction and
impact on dimethyl sulphide formation during beer storage. Journal of the Institute of Brewing, 125(1),
69–74. https://doi.org/10.1002/jib.531
6. Bamforth, C. W. (Ed.). (2009). Beer. Elsevier. https://doi.org/10.1016/B978-0-12-669201-3.X0001-2
7. Bamforth, C. W., & Lewis, M. J. (2007). Essays in Brewing Science. Springer US.
https://doi.org/10.1007/0-387-33011-9
8. Bamforth, C. W., Muller, R. E., & Walker, M. D. (1993). Oxygen and Oxygen Radicals in Malting
and Brewing: A Review. Journal of the American Society of Brewing Chemists, 51(3), 79–88.
https://doi.org/10.1094/ASBCJ-51-0079
9. Bamforth, C. W., & Parsons, R. (1985). New Procedures to Improve the Flavor Stability of Beer.
Journal of the American Society of Brewing Chemists, 43(4), 197–202.
https://doi.org/10.1094/ASBCJ-43-0197
10. Barnette, B. M., & Shellhammer, T. H. (2019). Evaluating the Impact of Dissolved Oxygen and Aging
on Dry-Hopped Aroma Stability in Beer. Journal of the American Society of Brewing Chemists, 77(3),
179–187. https://doi.org/10.1080/03610470.2019.1603002
11. Boccorh, R., & Paterson, A. (2002). Variations in flavour stability in lager beers. 6th Sensometric
Meeting, Dortmund, Germany.
12. Bogdan, P., & Kordialik-Bogacka, E. (2017). Alternatives to malt in brewing. Trends in Food Science
& Technology, 65, 1–9. https://doi.org/10.1016/j.tifs.2017.05.001
13. Bravo, A., Herrera, J. C., Scherer, E., Ju-Nam, Y., Rübsam, H., Madrid, J., Zufall, C., & Rangel-Aldao,
R. (2008). Formation of α-Dicarbonyl Compounds in Beer during Storage of Pilsner. Journal of
Agricultural and Food Chemistry, 56(11), 4134–4144. https://doi.org/10.1021/jf703696p
14. Bravo, A., Scherer, E., Madrid, J., Herrera, J., Virtanen, H., & Rangel-Aldao, R. (2001). Identification
of alfa-dicarbonylic compounds in aged beers: their role in beer aging process.
15. Brey, S. E., Bryce, J. H., & Stewart, G. G. (2002). The Loss of Hydrophobic Polypeptides during
Fermentation and Conditioning of High Gravity and Low Gravity Brewed Beer. Journal of the Institute
of Brewing, 108(4), 424–433. https://doi.org/10.1002/j.2050-0416.2002.tb00571.x

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 13
Vol. XXVIII (2024), no. 1
16. Bushnell, S. E., Guinard, J.-X., & Bamforth, C. W. (2003). Effects of Sulfur Dioxide and
Polyvinylpolypyrrolidone on the Flavor Stability of Beer as Measured by Sensory and Chemical
Analysis. Journal of the American Society of Brewing Chemists, 61(3), 133–141.
https://doi.org/10.1094/ASBCJ-61-0133
17. Caballero, I., Blanco, C. A., & Porras, M. (2012). Iso-α-acids, bitterness and loss of beer quality during
storage. Trends in Food Science & Technology, 26(1), 21–30.
https://doi.org/10.1016/j.tifs.2012.01.001
18. Callemien, D., & Collin, S. (2007). Involvement of Flavanoids in Beer Color Instability during
Storage. Journal of Agricultural and Food Chemistry, 55(22), 9066–9073.
https://doi.org/10.1021/jf0716230
19. Callemien, D., & Collin, S. (2009). Structure, Organoleptic Properties, Quantification Methods, and
Stability of Phenolic Compounds in Beer—A Review. Food Reviews International, 26(1), 1–84.
https://doi.org/10.1080/87559120903157954
20. Cao, L., Zhou, G., Guo, P., & Li, Y. (2011). Influence of Pasteurising Intensity on Beer Flavour
Stability. Journal of the Institute of Brewing, 117(4), 587–592. https://doi.org/10.1002/j.2050-
0416.2011.tb00508.x
21. Carneiro, J. R., Guido, L. F., Almeida, P. J., Rodrigues, J. A., & Barros, A. A. (2006). The impact of
sulphur dioxide and oxygen on the behaviour of 2‐furaldehyde in beer: an industrial approach.
International Journal of Food Science & Technology, 41(5), 545–552. https://doi.org/10.1111/j.1365-
2621.2005.01104.x
22. Chen, D.-Q., Zou, C., Huang, Y.-B., Zhu, X., Contursi, P., Yin, J.-F., & Xu, Y.-Q. (2023). Adding
functional properties to beer with jasmine tea extract. Frontiers in Nutrition, 10.
https://doi.org/10.3389/fnut.2023.1109109
23. Chevance, F., Guyot-Declerck, C., Dupont, J., & Collin, S. (2002). Investigation of the β-
Damascenone Level in Fresh and Aged Commercial Beers. Journal of Agricultural and Food
Chemistry, 50(13), 3818–3821. https://doi.org/10.1021/jf020085i
24. Chrisfield, B. J., Hopfer, H., & Elias, R. J. (2020). Impact of Copper Fungicide Use in Hop Production
on the Total Metal Content and Stability of Wort and Dry-Hopped Beer. Beverages, 6(3), 48.
https://doi.org/10.3390/beverages6030048
25. Ciosek, A., Rusiecka, I., & Poreda, A. (2020). Sour beer production: impact of pitching sequence of
yeast and lactic acid bacteria. Journal of the Institute of Brewing, 126(1), 53–58.
https://doi.org/10.1002/jib.590
26. Cooman, L., Aerts, G., Overmeire, H., & Keukeleire, D. (2000). Alterations of the Profiles of Iso-α-
Acids During Beer Ageing, Marked Instability of Trans-Iso-α-Acids and Implications for Beer
Bitterness Consistency in Relation to Tetrahydroiso-α-Acids. Journal of the Institute of Brewing,
106(3), 169–178. https://doi.org/10.1002/j.2050-0416.2000.tb00054.x
27. Cooper, D. J., Stewart, G. G., & Bryce, J. H. (1998). Some reasons why high gravity brewing has a
negative effect on head retention. Journal of the Institute of Brewing, 104(2), 83–87.
https://doi.org/10.1002/j.2050-0416.1998.tb00979.x
28. Cordente, Antonio. G., Capone, D. L., & Curtin, C. D. (2015). Unravelling glutathione conjugate
catabolism in Saccharomyces cerevisiae: the role of glutathione/dipeptide transporters and vacuolar
function in the release of volatile sulfur compounds 3-mercaptohexan-1-ol and 4-mercapto-4-
methylpentan-2-one. Applied Microbiology and Biotechnology, 99(22), 9709–9722.
https://doi.org/10.1007/s00253-015-6833-5
29. Cortese, M., Gigliobianco, M. R., Peregrina, D. V., Sagratini, G., Censi, R., & Di Martino, P. (2020).
Quantification of phenolic compounds in different types of crafts beers, worts, starting and spent
ingredients by liquid chromatography-tandem mass spectrometry. Journal of Chromatography A,
1612, 460622. https://doi.org/10.1016/j.chroma.2019.460622
30. Dale, A. R., Pollock, J. R. A., Moll, M., & That, V. (1977). A means to reduce formation of precursors
of 2-trans-nonenal in brewing*. Journal of the Institute of Brewing, 83(2), 88–91.
https://doi.org/10.1002/j.2050-0416.1977.tb06419.x
31. de Almeida, N. E. C., do Nascimento, E. S. P., & Cardoso, D. R. (2012). On the Reaction of Lupulones,
Hops β-Acids, with 1-Hydroxyethyl Radical. Journal of Agricultural and Food Chemistry, 60(42),
10649–10656. https://doi.org/10.1021/jf302708c
32. De Francesco, G., Bravi, E., Sanarica, E., Marconi, O., Cappelletti, F., & Perretti, G. (2020). Effect of
Addition of Different Phenolic-Rich Extracts on Beer Flavour Stability. Foods, 9(11), 1638.
https://doi.org/10.3390/foods9111638

Klimczak et al., Factors affecting beer quality during storage – A review 14
33. De Keukeleire, D., Heyerick, A., Huvaere, K., Skibsted, L. H., & Andersen, M. L. (2008). Beer
lightstruck flavor: The full story. Cerevisia, 33, 133–144.
34. Depraetere, S. A., Delvaux, F., Schutter, D. De, Williams, I. S., Winderickx, J., & Delvaux, F. R.
(2008). The influence of wort aeration and yeast preoxygenation on beer staling processes. Food
Chemistry, 107(1), 242–249. https://doi.org/10.1016/j.foodchem.2007.08.023
35. Drexler. (2010). The Influence of Hop Harvest Date on Flavor Stability in Dry-hopped Beers.
Technical Quarterly. https://doi.org/10.1094/TQ-47-1-0219-01
36. Duyvis, M., Laane, C., Hilhorst, R., Schmedding, D., & Evans, D. (2000). The use of Riboflavin
Binding Protein to improve flavour stability in beer. In: Proceedings of the Second European
Symposium on Enzymes in Grain Processing : ESEGP-2, Helsinki, 1999. - [S.l] : [S.n.], 2000.
37. Farber, M., & Barth, R. (2019). Mastering Brewing Science. Quality and Production. John Wiley &
Sons.
38. Ferreira, S. C., & Collin, S. (2021). Fate of Hop and Fermentation Odorants in Commercial Belgian
Dry-Hopped Beers over 2 Years of Bottle Storage: Key-Role of Oxidation and Hop Esterases. Journal
of the American Society of Brewing Chemists, 79(3), 259–271.
https://doi.org/10.1080/03610470.2020.1843898
39. Food waste and food waste prevention - estimates. Eurostat (2023).
https://ec.europa.eu/eurostat/statistics-explained/SEPDF/cache/110448.pdf
40. François, N., Guyot-Declerck, C., Hug, B., Callemien, D., Govaerts, B., & Collin, S. (2006). Beer
astringency assessed by time–intensity and quantitative descriptive analysis: Influence of pH and
accelerated aging. Food Quality and Preference, 17(6), 445–452.
https://doi.org/10.1016/j.foodqual.2005.05.008
41. Gagula, G., Mastanjević, K., Mastanjević, K., Krstanović, V., Horvat, D., & Magdić, D. (2020). The
influence of packaging material on volatile compounds of pale lager beer. Food Packaging and Shelf
Life, 24, 100496. https://doi.org/10.1016/j.fpsl.2020.100496
42. Gahr, A., Forster, A., Schüll, F., Faltermaier, S., & Kellerer, F. (2020). The Stability of Bitter
Substances in Beer During the Ageing Process. BrewingScience, 73(11–12), 149–157.
https://doi.org/10.23763/BrSc20-20gahr
43. Gernat, D. C., Brouwer, E., & Ottens, M. (2020). Aldehydes as Wort Off-Flavours in Alcohol-Free
Beers—Origin and Control. Food and Bioprocess Technology, 13(2), 195–216.
https://doi.org/10.1007/s11947-019-02374-z
44. Gibson, B., Aumala, V., Heiniö, R.-L., Mikkelson, A., & Honkapää, K. (2018). Differential evolution
of Strecker and non-Strecker aldehydes during aging of pale and dark beers. Journal of Cereal Science,
83, 130–138. https://doi.org/10.1016/j.jcs.2018.08.009
45. Gijs, L., Chevance, F., Jerkovic, V., & Collin, S. (2002). How Low pH Can Intensify β-Damascenone
and Dimethyl Trisulfide Production through Beer Aging. Journal of Agricultural and Food Chemistry,
50(20), 5612–5616. https://doi.org/10.1021/jf020563p
46. Gijs, L., Perpète, P., Timmermans, A., & Collin, S. (2000). 3-Methylthiopropionaldehyde as Precursor
of Dimethyl Trisulfide in Aged Beers. Journal of Agricultural and Food Chemistry, 48(12), 6196–
6199. https://doi.org/10.1021/jf0007380
47. Grigsby, J. H., & Palamand, S. R. (1977). A Colorimetric Procedure for the Measurement of Dimethyl
Sulfide in Water, Wort, and Beer. Journal of the American Society of Brewing Chemists, 35(2), 43–
48. https://doi.org/10.1094/ASBCJ-35-0043
48. Guan, X., Nie, C., Guo, Y., & Zhang, J. (2019). Changes of Hop-Derived Aroma Compounds in India
Pale Ale during Brewing and Storage. ETP International Journal of Food Engineering, 50–57.
https://doi.org/10.18178/ijfe.5.1.50-57
49. Guglielmotti, M., Passaghe, P., & Buiatti, S. (2020). Use of olive ( Olea europaea L .) leaves as beer
ingredient, and their influence on beer chemical composition and antioxidant activity. Journal of Food
Science, 85(8), 2278–2285. https://doi.org/10.1111/1750-3841.15318
50. Guido, L. (2004). The impact of the physiological condition of the pitching yeast on beer flavour
stability: an industrial approach. Food Chemistry, 87(2), 187–193.
https://doi.org/10.1016/j.foodchem.2003.10.033
51. Guido, L. F., Boivin, P., Benismail, N., Gonçalves, C. R., & Barros, A. A. (2005). An early
development of the nonenal potential in the malting process. European Food Research and
Technology, 220(2), 200–206. https://doi.org/10.1007/s00217-004-1079-y
52. Guido, L. F., Curto, A. F., Boivin, P., Benismail, N., Gonçalves, C. R., & Barros, A. A. (2007).
Correlation of Malt Quality Parameters and Beer Flavor Stability: Multivariate Analysis. Journal of
Agricultural and Food Chemistry, 55(3), 728–733. https://doi.org/10.1021/jf0623079

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 15
Vol. XXVIII (2024), no. 1
53. Habschied, K., Košir, I. J., Krstanović, V., Kumrić, G., & Mastanjević, K. (2021). Beer polyphenols—
bitterness, astringency, and off-flavors. In Beverages (Vol. 7, Issue 2). MDPI AG.
https://doi.org/10.3390/beverages7020038
54. Hammond, J., Brennan, M., & Price, A. (1999). The Control of Microbial Spoilage of Beer*. Journal
of the Institute of Brewing, 105(2), 113–120. https://doi.org/10.1002/j.2050-0416.1999.tb00014.x
55. Haslbeck, K., Bub, S., Schönberger, C., Zarnkow, M., Jacob, F., & Coelhan, M. (2017). On the fate of
β-myrcene during fermentation-the role of stripping and uptake of hop oil components by brewer’s
yeast in dry-hopped wort and beer. BrewingScience, 70(11–12), 159–169.
https://doi.org/10.23763/BrSc17-16haslbeck
56. He, G., Du, J., Zhang, K., Wei, G., & Wang, W. (2012). Antioxidant capability and potableness of
fresh cloudy wheat beer stored at different temperatures. Journal of the Institute of Brewing, 118(4),
386–392. https://doi.org/10.1002/jib.54
57. Hellwig, M., & Henle, T. (2020). Maillard Reaction Products in Different Types of Brewing Malt.
Journal of Agricultural and Food Chemistry, 68(48), 14274–14285.
https://doi.org/10.1021/acs.jafc.0c06193
58. Hempel, A., O’Sullivan, M. G., Papkovsky, D. B., & Kerry, J. P. (2013). Use of optical oxygen sensors
to monitor residual oxygen in pre- and post-pasteurised bottled beer and its effect on sensory attributes
and product acceptability during simulated commercial storage. LWT - Food Science and Technology,
50(1), 226–231. https://doi.org/10.1016/j.lwt.2012.05.026
59. Herrmann, M., Klotzbücher, B., Wurzbacher, M., Hanke, S., Kattein, U., Back, W., Becker, T., &
Krottenthaler, M. (2010). A New Validation of Relevant Substances for the Evaluation of Beer Aging
Depending on the Employed Boiling System. Journal of the Institute of Brewing, 116(1), 41–48.
https://doi.org/10.1002/j.2050-0416.2010.tb00396.x
60. Heuberger, A. L., Broeckling, C. D., Lewis, M. R., Salazar, L., Bouckaert, P., & Prenni, J. E. (2012).
Metabolomic profiling of beer reveals effect of temperature on non-volatile small molecules during
short-term storage. Food Chemistry, 135(3), 1284–1289.
https://doi.org/10.1016/j.foodchem.2012.05.048
61. Heuberger, A. L., Broeckling, C. D., Sedin, D., Holbrook, C., Barr, L., Kirkpatrick, K., & Prenni, J.
E. (2016). Evaluation of non-volatile metabolites in beer stored at high temperature and utility as an
accelerated method to predict flavour stability. Food Chemistry, 200, 301–307.
https://doi.org/10.1016/j.foodchem.2016.01.022
62. Hill, A., & Stewart, G. (2019). Free Amino Nitrogen in Brewing. Fermentation, 5(1), 22.
https://doi.org/10.3390/fermentation5010022
63. Hoff, S., Lund, M. N., Petersen, M. A., Frank, W., & Andersen, M. L. (2013). Storage stability of
pasteurized non-filtered beer. Journal of the Institute of Brewing, n/a-n/a.
https://doi.org/10.1002/jib.85
64. Hrabia, O., Ditrych, M., Ciosek, A., Fulara, K., Andersen, M. L., & Poreda, A. (2022). Effect of dry
hopping on the oxidative stability of beer. Food Chemistry, 394, 133480.
https://doi.org/10.1016/j.foodchem.2022.133480
65. Intelmann, D., Haseleu, G., Dunkel, A., Lagemann, A., Stephan, A., & Hofmann, T. (2011).
Comprehensive sensomics analysis of hop-derived bitter compounds during storage of beer. Journal
of Agricultural and Food Chemistry, 59(5), 1939–1953. https://doi.org/10.1021/jf104392y
66. Jaskula, B., Syryn, E., Goiris, K., De Rouck, G., Van Opstaele, F., De Clippeleer, J., Aerts, G., & De
Cooman, L. (2007). Hopping technology in relation to beer bitterness consistency and flavor stability.
Journal of the American Society of Brewing Chemists, 65(1), 38–46. https://doi.org/10.1094/ASBCJ-
2007-0112-03
67. Jaskula-Goiris, B., De Causmaecker, B., De Rouck, G., Cooman, L., & Aerts, G. (2011). Detailed
multivariate modeling of beer staling in commercial pale lagers. BrewingScience, 64, 119–139.
68. Jaskula-Goiris, B., Goiris, K., Syryn, E., Van Opstaele, F., De Rouck, G., Aerts, G., & De Cooman, L.
(2014). The use of hop polyphenols during brewing to improve flavor quality and stability of pilsner
beer. Journal of the American Society of Brewing Chemists, 72(3), 175–183.
https://doi.org/10.1094/ASBCJ-2014-0616-01
69. Jenkins, D., James, S., Dehrmann, F., Smart, K., & Cook, D. (2018). Impacts of Copper, Iron, and
Manganese Metal Ions on the EPR Assessment of Beer Oxidative Stability. Journal of the American
Society of Brewing Chemists, 76(1), 50–57. https://doi.org/10.1080/03610470.2017.1402585
70. Jenkins, D., James, S., Dehrmann, F., Smart, K., & Cook, D. (2021). The influence of yeast strain on
the oxidative stability of beer. Journal of the Institute of Brewing, 127(3), 248–255.
https://doi.org/10.1002/jib.650

Klimczak et al., Factors affecting beer quality during storage – A review 16
71. Jeon, S. H., Kim, N. H., Shim, M. B., Jeon, Y. W., Ahn, J. H., Lee, S. H., Hwang, I. G., & Rhee, M.
S. (2015). Microbiological Diversity and Prevalence of Spoilage and Pathogenic Bacteria in
Commercial Fermented Alcoholic Beverages (Beer, Fruit Wine, Refined Rice Wine, and Yakju).
Journal of Food Protection, 78(4), 812–818. https://doi.org/10.4315/0362-028X.JFP-14-431
72. Kaneda, H., Kano, Y., Sekine, T., Ishii, S., Takahashi, K., & Koshino, S. (1992). Effect of pitching
yeast and wort preparation on flavor stability of beer. Journal of Fermentation and Bioengineering,
73(6), 456–460. https://doi.org/10.1016/0922-338X(92)90137-J
73. Kaneda, H., Takashio, M., Osawa, T., Kawakishi, S., & Tamaki, T. (1996). Behavior of Sulfites During
Fermentation and Storage of Beer. Journal of the American Society of Brewing Chemists, 54(2), 115–
120. https://doi.org/10.1094/ASBCJ-54-0115
74. Kaneda, H., Takashio, M., Tamaki, T., & Osawa, T. (1997). Influence of ph on flavour staling during
beer storage. Journal of the Institute of Brewing, 103(1), 21–23. https://doi.org/10.1002/j.2050-
0416.1997.tb00932.x
75. Kemp, O., Hofmann, S., Braumann, I., Jensen, S., Fenton, A., & Oladokun, O. (2021). Changes in key
hop‐derived compounds and their impact on perceived dry‐hop flavour in beers after storage at cold
and ambient temperature. Journal of the Institute of Brewing, 127(4), 367–384.
https://doi.org/10.1002/jib.667
76. Kim, S. A., Kim, N. H., Lee, S. H., Hwang, I. G., & Rhee, M. S. (2014). Survival of Foodborne
Pathogenic Bacteria (Bacillus cereus, Escherichia coli O157:H7, Salmonella enterica Serovar
Typhimurium, Staphylococcus aureus, and Listeria monocytogenes) and Bacillus cereus Spores in
Fermented Alcoholic Beverages (Beer and Refined Rice Wine). Journal of Food Protection, 77(3),
419–426. https://doi.org/10.4315/0362-028X.JFP-13-234
77. Krogerus, K., & Gibson, B. (2020). A re-evaluation of diastatic Saccharomyces cerevisiae strains and
their role in brewing. Applied Microbiology and Biotechnology, 104(9), 3745–3756.
https://doi.org/10.1007/s00253-020-10531-0
78. Kucharczyk, K., & Tuszyński, T. (2017). The effect of wort aeration on fermentation, maturation and
volatile components of beer produced on an industrial scale. Journal of the Institute of Brewing,
123(1), 31–38. https://doi.org/10.1002/jib.392
79. Kunz, T., Woest, H., Lee, E.-J., Müller, C., & Methner, F.-J. (2011). Improvement of the Oxidative
Wort and Beer Stability by Increased Unmalted Barley Proportion. Brewing Science, 64.
80. L’Anthoën, N. C., & Ingledew, W. M. (1996). Heat Resistance of Bacteria in Alcohol-Free Beer.
Journal of the American Society of Brewing Chemists, 54(1), 32–36. https://doi.org/10.1094/ASBCJ-
54-0032
81. Lea, A. G. H., & Piggott, J. R. (Eds.). (2003). Fermented Beverage Production. Springer US.
https://doi.org/10.1007/978-1-4615-0187-9
82. Lehnhardt, F., Becker, T., & Gastl, M. (2020). Flavor stability assessment of lager beer: what we can
learn by comparing established methods. European Food Research and Technology, 246(5), 1105–
1118. https://doi.org/10.1007/s00217-020-03477-0
83. Lermusieau, G., Noël, S., Liégeois, C., & Collin, S. (1999). Nonoxidative Mechanism for
Development of Trans -2-Nonenal in Beer. Journal of the American Society of Brewing Chemists,
57(1), 29–33. https://doi.org/10.1094/ASBCJ-57-0029
84. Liguori, L., De Francesco, G., Orilio, P., Perretti, G., & Albanese, D. (2021). Influence of malt
composition on the quality of a top fermented beer. Journal of Food Science and Technology, 58(6),
2295–2303. https://doi.org/10.1007/s13197-020-04740-8
85. Lipp, M. (2021). Food safety is truly everyone’s business. Journal of Consumer Protection and Food
Safety, 16(2), 107–108. https://doi.org/10.1007/s00003-021-01325-1
86. Liu, C., Shen, Y., Yin, X., Peng, L., & Li, Q. (2014). Influence of Pasteurization and Microfiltration
on Beer Aging and Anti-Aging Levels. Journal of the American Society of Brewing Chemists, 72(4),
285–295. https://doi.org/10.1094/ASBCJ-2014-0925-01
87. López, M. G., Roche, E., & Rodríguez, E. (2021). Contaminant microbiota in craft beers. Journal of
Microbiology, Biotechnology and Food Sciences, 9(6), 1181–1186.
https://doi.org/10.15414/jmbfs.2020.9.6.1181-1186
88. Lorencová, E., Salek, R. N., Černošková, I., & Buňka, F. (2019). Evaluation of force-carbonated
Czech-type lager beer quality during storage in relation to the applied type of packaging. Food Control,
106, 106706. https://doi.org/10.1016/j.foodcont.2019.106706
89. Lund, M. N., & Andersen, M. L. (2011). Detection of Thiol Groups in Beer and Their Correlation with
Oxidative Stability. Journal of the American Society of Brewing Chemists, 69(3), 163–169.
https://doi.org/10.1094/ASBCJ-2011-0620-01

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 17
Vol. XXVIII (2024), no. 1
90. Lund, M. N., Hoff, S., Berner, T. S., Lametsch, R., & Andersen, M. L. (2012). Effect of Pasteurization
on the Protein Composition and Oxidative Stability of Beer during Storage. Journal of Agricultural
and Food Chemistry, 60(50), 12362–12370. https://doi.org/10.1021/jf303044a
91. Lund, M. N., Krämer, A. C., & Andersen, M. L. (2015). Antioxidative Mechanisms of Sulfite and
Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer. Journal of
Agricultural and Food Chemistry, 63(37), 8254–8261. https://doi.org/10.1021/acs.jafc.5b02617
92. Maia, C., Cunha, S., Debyser, W., & Cook, D. (2023). Impacts of Adjunct Incorporation on Flavor
Stability Metrics at Early Stages of Beer Production. Journal of the American Society of Brewing
Chemists, 81(1), 54–65. https://doi.org/10.1080/03610470.2021.1993054
93. Marcos, A., Serra-Majem, L., Pérez-Jiménez, F., Pascual, V., Tinahones, F. J., & Estruch, R. (2021).
Moderate Consumption of Beer and Its Effects on Cardiovascular and Metabolic Health: An Updated
Review of Recent Scientific Evidence. Nutrients, 13(3), 879. https://doi.org/10.3390/nu13030879
94. Menz, G., Aldred, P., & Vriesekoop, F. (2011). Growth and Survival of Foodborne Pathogens in Beer.
Journal of Food Protection, 74(10), 1670–1675. https://doi.org/10.4315/0362-028X.JFP-10-546
95. Menz, G., Andrighetto, C., Lombardi, A., Corich, V., Aldred, P., & Vriesekoop, F. (2010). Isolation,
Identification, and Characterisation of Beer-Spoilage Lactic Acid Bacteria from Microbrewed Beer
from Victoria, Australia. Journal of the Institute of Brewing, 116(1), 14–22.
https://doi.org/10.1002/j.2050-0416.2010.tb00393.x
96. Menz, G., Vriesekoop, F., Zarei, M., Zhu, B., & Aldred, P. (2010). The growth and survival of food-
borne pathogens in sweet and fermenting brewers’ wort. International Journal of Food Microbiology,
140(1), 19–25. https://doi.org/10.1016/j.ijfoodmicro.2010.02.018
97. Mertens, T., Kunz, T., Wietstock, P. C., & Methner, F. (2021). Complexation of transition metals by
chelators added during mashing and impact on beer stability. Journal of the Institute of Brewing,
127(4), 345–357. https://doi.org/10.1002/jib.673
98. Mikyška, A., Hrabák, M., Hašková, D., & Šrogl, J. (2002). The Role of Malt and Hop Polyphenols in
Beer Quality, Flavour and Haze Stability. Journal of the Institute of Brewing, 108(1), 78–85.
https://doi.org/10.1002/j.2050-0416.2002.tb00128.x
99. Mikyška, A., Jurková, M., Horák, T., & Slabý, M. (2022). Study of the influence of hop polyphenols
on the sensory stability of lager beer. European Food Research and Technology, 248(2), 533–542.
https://doi.org/10.1007/s00217-021-03900-0
100. Mikyška, A., Krofta, K., Hašková, D., Čulík, J., & Čejka, P. (2011). The Influence of Hopping on
Formation of Carbonyl Compounds During Storage of Beer. Journal of the Institute of Brewing,
117(1), 47–54. https://doi.org/10.1002/j.2050-0416.2011.tb00442.x
101. Mochaba, F., O’Connor-Cox, E. S. C., & Axcell, B. C. (1996). Effects of Yeast Quality on the
Accumulation and Release of Metals Causing Beer Instability. Journal of the American Society of
Brewing Chemists, 54(3), 164–171. https://doi.org/10.1094/ASBCJ-54-0164
102. Mondaca‐Navarro, B. A., Ávila‐Villa, L. A., González‐Córdova, A. F., López‐Cervantes, J., Sánchez‐
Machado, D. I., Campas‐Baypoli, O. N., & Rodríguez‐Ramírez, R. (2017). Antioxidant and chelating
capacity of Maillard reaction products in amino acid‐sugar model systems: applications for food
processing. Journal of the Science of Food and Agriculture, 97(11), 3522–3529.
https://doi.org/10.1002/jsfa.8206
103. Moreno, S. R., Curtis, S. J., Sarkhosh, A., Sarnoski, P. J., Sims, C. A., Dreyer, E., Rudolph, A. B.,
Thompson-Witrick, K. A., & MacIntosh, A. J. (2022). Considerations When Brewing with Fruit
Juices: A Review and Case Study Using Peaches. Fermentation, 8(10), 567.
https://doi.org/10.3390/fermentation8100567
104. Munford, A. R. G., Alvarenga, V. O., Prado-Silva, L. do, Crucello, A., Campagnollo, F. B., Chaves,
R. D., Oteiza, J. M., & Sant’Ana, A. S. (2017). Sporeforming bacteria in beer: Occurrence, diversity,
presence of hop resistance genes and fate in alcohol-free and lager beers. Food Control, 81, 126–136.
https://doi.org/10.1016/j.foodcont.2017.06.003
105. Munoz-Insa, A., Gastl, M., & Becker, T. (2015). Use of Polyphenol-Rich Hop Products to Reduce
Sunstruck Flavor in Beer. Journal of the American Society of Brewing Chemists, 73(3), 228–235.
https://doi.org/10.1094/ASBCJ-2015-0625-01
106. Murmann, A. N., Bevilacqua, M., Danielsen, B. P., Jansson, T., Engholm-Keller, K., Poojary, M. M.,
Arneborg, N., & Lund, M. N. (2023). The impact of lager brewing yeasts on flavor stability of pilot-
scale beer during storage. European Food Research and Technology. https://doi.org/10.1007/s00217-
023-04421-8
107. Mussche, R. A., & Pauw, C. (1999). Total Stabilisation of Beer in a Single Operation*. Journal of the
Institute of Brewing, 105(6), 386–391. https://doi.org/10.1002/j.2050-0416.1999.tb00030.x

Klimczak et al., Factors affecting beer quality during storage – A review 18
108. Nizet, S., Peeters, F., Gros, J., & Collin, S. (2014). Odorant Polyfunctional Thiols Issued from Bottle
Beer Refermentation. In V. Ferreira & R. Lopez (Eds.), Flavour Science (pp. 227–230). Elsevier.
https://doi.org/10.1016/B978-0-12-398549-1.00043-X
109. Nooshkam, M., Varidi, M., & Bashash, M. (2019). The Maillard reaction products as food-born
antioxidant and antibrowning agents in model and real food systems. Food Chemistry, 275, 644–660.
https://doi.org/10.1016/j.foodchem.2018.09.083
110. Okaru, A. O., & Lachenmeier, D. W. (2022). Defining No and Low (NoLo) Alcohol Products.
Nutrients, 14(18), 3873. https://doi.org/10.3390/nu14183873
111. Oladokun, O., Tarrega, A., James, S., Smart, K., Hort, J., & Cook, D. (2016). The impact of hop bitter
acid and polyphenol profiles on the perceived bitterness of beer. Food Chemistry, 205, 212–220.
https://doi.org/10.1016/j.foodchem.2016.03.023
112. Oldham, R. C., & Held, M. A. (2023). Methods for detection and identification of beer-spoilage
microbes. Frontiers in Microbiology, 14. https://doi.org/10.3389/fmicb.2023.1217704
113. Parkin, E., & Shellhammer, T. (2017). Toward understanding the bitterness of dry-hopped beer.
Journal of the American Society of Brewing Chemists, 75(4), 363–368.
https://doi.org/10.1094/ASBCJ-2017-4311-01
114. Preedy, V. R. (Ed.). (2009). Beer in Health and Disease Prevention.
115. Quain, D. E. (2021). The enhanced susceptibility of alcohol‐free and low alcohol beers to
microbiological spoilage: implications for draught dispense. Journal of the Institute of Brewing,
127(4), 406–416. https://doi.org/10.1002/jib.670
116. Rettberg, N., Schubert, C., Dennenlöhr, J., Thörner, S., Knoke, L., & Maxminer, J. (2020). Instability
of Hop-Derived 2-Methylbutyl Isobutyrate during Aging of Commercial Pasteurized and
Unpasteurized Ales. Journal of the American Society of Brewing Chemists, 78(3), 175–184.
https://doi.org/10.1080/03610470.2020.1738742
117. Rivero, D., Pérez-Magariño, S., González-Sanjosé, M. L., Valls-Belles, V., Codoñer, P., & Muñiz, P.
(2005). Inhibition of Induced DNA Oxidative Damage by Beers: Correlation with the Content of
Polyphenols and Melanoidins. Journal of Agricultural and Food Chemistry, 53(9), 3637–3642.
https://doi.org/10.1021/jf048146v
118. Rodriguez-Bencomo, J. J., Muñoz-González, C., Martín-Álvarez, P. J., Lázaro, E., Mancebo, R.,
Castañé, X., & Pozo-Bayón, M. A. (2012). Optimization of a HS-SPME-GC-MS Procedure for Beer
Volatile Profiling Using Response Surface Methodology: Application to Follow Aroma Stability of
Beers Under Different Storage Conditions. Food Analytical Methods, 5(6), 1386–1397.
https://doi.org/10.1007/s12161-012-9390-x
119. Rodríguez-Saavedra, M., González de Llano, D., & Moreno-Arribas, M. V. (2020). Beer spoilage
lactic acid bacteria from craft brewery microbiota: Microbiological quality and food safety. Food
Research International, 138, 109762. https://doi.org/10.1016/j.foodres.2020.109762
120. Saison, D., De Schutter, D. P., Overlaet-Michiels, W., Delvaux, F., & Delvaux, F. R. (2009). Effect of
Fermentation Conditions on Staling Indicators in Beer. Journal of the American Society of Brewing
Chemists, 67(4), 222–228. https://doi.org/10.1094/ASBCJ-2009-0720-02
121. Saison, D., De Schutter, D. P., Uyttenhove, B., Delvaux, F., & Delvaux, F. R. (2009). Contribution of
staling compounds to the aged flavour of lager beer by studying their flavour thresholds. Food
Chemistry, 114(4), 1206–1215. https://doi.org/10.1016/j.foodchem.2008.10.078
122. Saison, D., De Schutter, D. P., Vanbeneden, N., Daenen, L., Delvaux, F., & Delvaux, F. R. (2010).
Decrease of Aged Beer Aroma by the Reducing Activity of Brewing Yeast. Journal of Agricultural
and Food Chemistry, 58(5), 3107–3115. https://doi.org/10.1021/jf9037387
123. Sakamoto, K., & Konings, W. N. (2003). Beer spoilage bacteria and hop resistance. International
Journal of Food Microbiology, 89(2–3), 105–124. https://doi.org/10.1016/S0168-1605(03)00153-3
124. Sakuma, S., Rikimaru, Y., Kobayashi, K., & Kowaka, M. (1991). Sunstruck Flavor Formation in Beer.
Journal of the American Society of Brewing Chemists, 49(4), 162–165.
https://doi.org/10.1094/ASBCJ-49-0162
125. Savel, J., Kosin, P., & Broz, A. (2010). Anaerobic and Aerobic Beer Aging. Czech Journal of Food
Sciences, 28, 18–26. https://doi.org/10.17221/161/2009-CJFS
126. Schubert, C., Lafontaine, S., Dennenlöhr, J., Thörner, S., & Rettberg, N. (2022). The influence of
storage conditions on the chemistry and flavor of hoppy ales. Food Chemistry, 395, 133616.
https://doi.org/10.1016/j.foodchem.2022.133616
127. Shimotsu, S., Asano, S., Iijima, K., Suzuki, K., Yamagishi, H., & Aizawa, M. (2015). Investigation of
beer-spoilage ability of Dekkera / Brettanomyces yeasts and development of multiplex PCR method

Acta Universitatis Cibiniensis Series E: FOOD TECHNOLOGY 19
Vol. XXVIII (2024), no. 1
for beer-spoilage yeasts. Journal of the Institute of Brewing, 121(2), 177–180.
https://doi.org/10.1002/jib.209
128. Shopska, V., Denkova-Kostova, R., Dzhivoderova-Zarcheva, M., Teneva, D., Denev, P., & Kostov,
G. (2021). Comparative Study on Phenolic Content and Antioxidant Activity of Different Malt Types.
Antioxidants, 10(7), 1124. https://doi.org/10.3390/antiox10071124
129. Siebert, K. J. (2009). Chapter 2 Haze in Beverages. In Advances in Food and Nutrition Research (Vol.
57, pp. 53–86). https://doi.org/10.1016/S1043-4526(09)57002-7
130. Silva Ferreira, C., Bodart, E., & Collin, S. (2019). Why Craft Brewers Should Be Advised to Use
Bottle Refermentation to Improve Late-Hopped Beer Stability. Beverages, 5(2), 39.
https://doi.org/10.3390/beverages5020039
131. Soares da Costa, M., Gonçalves, C., Ferreira, A., Ibsen, C., Guedes de Pinho, P., & Silva Ferreira, A.
C. (2004). Further Insights into the Role of Methional and Phenylacetaldehyde in Lager Beer Flavor
Stability. Journal of Agricultural and Food Chemistry, 52(26), 7911–7917.
https://doi.org/10.1021/jf049178l
132. Sohrabvandi, S., Mousavi, S. M., Razavi, S. H., Mortazavian, A. M., & Rezaei, K. (2010). Alcohol-
free Beer: Methods of Production, Sensorial Defects, and Healthful Effects. Food Reviews
International, 26(4), 335–352. https://doi.org/10.1080/87559129.2010.496022
133. Sohrabvandi, S., Razavi, S., Mousavi, M., & Mortazavian, A. (2010). Viability of Probiotic Bacteria
in Low Alcohol- and Non-Alcoholic Beer During Refrigerated Storage. The Philippine Agriculturist,
93, 24–28.
134. Srinivasan, V., Goldberg, D., & Haas, G. J. (2004). Contributions to the antimicrobial spectrum of hop
constituents. Economic Botany, 58(1), S230–S238. https://doi.org/10.1663/0013-
0001(2004)58[S230:CTTASO]2.0.CO;2
135. Steiner, E., Becker, T., & Gastl, M. (2010). Turbidity and Haze Formation in Beer - Insights and
Overview. Journal of the Institute of Brewing, 116(4), 360–368. https://doi.org/10.1002/j.2050-
0416.2010.tb00787.x
136. Stevens, J. C. (1996). Detection of Tastes in Mixture with Other Tastes: Issues of Masking and Aging.
Chemical Senses, 21(2), 211–221. https://doi.org/10.1093/chemse/21.2.211
137. Stewart, G. G., Russell, I., & Anstruther, A. (Eds.). (2017). Handbook of Brewing. CRC Press.
https://doi.org/10.1201/9781351228336
138. Štulíková, K., Novák, J., Vlček, J., Šavel, J., Košin, P., & Dostálek, P. (2020). Bottle Conditioning:
Technology and Mechanisms Applied in Refermented Beers. Beverages, 6(3), 56.
https://doi.org/10.3390/beverages6030056
139. Štulíková, K., Vrzal, T., Kubizniaková, P., Enge, J., Matoulková, D., & Brányik, T. (2021). Spoilage
of bottled lager beer contaminated with Saccharomyces cerevisiae var. diastaticus. Journal of the
Institute of Brewing, 127(3), 256–261. https://doi.org/10.1002/jib.653
140. Timke, M., Wang-Lieu, N. Q., Altendorf, K., & Lipski, A. (2008). Identity, beer spoiling and biofilm
forming potential of yeasts from beer bottling plant associated biofilms. Antonie van Leeuwenhoek,
93(1–2), 151–161. https://doi.org/10.1007/s10482-007-9189-8
141. Titus, B. M., Lerno, L. A., Beaver, J., Byrnes, N. K., Heymann, H., & Oberholster, A. (2021). Impact
of dry hopping on beer flavor stability. Foods, 10(6). https://doi.org/10.3390/foods10061264
142. Tran, T. T. H., Cibaka, K. M.-L., & Collin, S. (2015). Polyfunctional Thiols in Fresh and Aged Belgian
Special Beers: Fate of Hop S -Cysteine Conjugates. Journal of the American Society of Brewing
Chemists, 73(1), 61–70. https://doi.org/10.1094/ASBCJ-2015-0130-01
143. Tsuji, H., & Mizuno, A. (2010). Volatile Compounds and the Changes in Their Concentration Levels
during Storage in Beers Containing Varying Malt Concentrations. Journal of Food Science, 75(1).
https://doi.org/10.1111/j.1750-3841.2009.01428.x
144. Valentoni, A., Santoru, A., Sanna, M., Fanari, M., Porcu, M. C., Fadda, A., Sanna, D., & Pretti, L.
(2022). Evolution of sensory analysis attributes and volatile aging markers in bottle fermented craft
beers during storage at different temperatures. Food Chemistry Advances, 1, 100151.
https://doi.org/10.1016/j.focha.2022.100151
145. Vanderhaegen, B., Delvaux, F., Daenen, L., Verachtert, H., & Delvaux, F. R. (2007). Aging
characteristics of different beer types. Food Chemistry, 103(2), 404–412.
https://doi.org/10.1016/j.foodchem.2006.07.062
146. Vanderhaegen, B., Neven, H., Coghe, S., Verstrepen, K. J., Verachtert, H., & Derdelinckx, G. (2003).
Evolution of Chemical and Sensory Properties during Aging of Top-Fermented Beer. Journal of
Agricultural and Food Chemistry, 51(23), 6782–6790. https://doi.org/10.1021/jf034631z

Klimczak et al., Factors affecting beer quality during storage – A review 20
147. Vanderhaegen, B., Neven, H., Verstrepen, K. J., Delvaux, F. R., Verachtert, H., & Derdelinckx, G.
(2004). Influence of the Brewing Process on Furfuryl Ethyl Ether Formation during Beer Aging.
Journal of Agricultural and Food Chemistry, 52(22), 6755–6764. https://doi.org/10.1021/jf0490854
148. Walters, M. T., Heasman, A. P., & Hughes, P. S. (1997a). Comparison of (+)—Catechin and Ferulic
Acid as Natural Antioxidants and Their Impact on Beer Flavor Stability. Part 1: Forced-Aging. Journal
of the American Society of Brewing Chemists, 55(2), 83–89. https://doi.org/10.1094/ASBCJ-55-0083
149. Walters, M. T., Heasman, A. P., & Hughes, P. S. (1997b). Comparison of (+)—Catechin and Ferulic
Acid as Natural Antioxidants and Their Impact on Beer Flavor Stability. Part 2: Extended Storage
Trials. Journal of the American Society of Brewing Chemists, 55(3), 91–98.
https://doi.org/10.1094/ASBCJ-55-0091
150. Wang, D., Sun, J., Zhang, W., Jia, F., Yang, Y., Lin, Z., Feng, J., & Pavlovic, M. (2006). Disruption
of Brewer’s Yeast Alcohol Dehydrogenase II Gene and Reduction of Acetaldehyde Content during
Brewery Fermentation. Journal of the American Society of Brewing Chemists, 64(4), 195–201.
https://doi.org/10.1094/ASBCJ-64-0195
151. Wang, W., Liu, Y., Sun, Z., Du, G., & Li, X. (2017). Hop resistance and beer-spoilage features of
foodborne Bacillus cereus newly isolated from filtration-sterilized draft beer. Annals of Microbiology,
67(1), 17–23. https://doi.org/10.1007/s13213-016-1232-4
152. Wang, Y., & Ye, L. (2021). Haze in Beer: Its Formation and Alleviating Strategies, from a Protein–
Polyphenol Complex Angle. Foods, 10(12), 3114. https://doi.org/10.3390/foods10123114
153. Wietstock, P. (2017). Free radical-mediated formation of aroma-active aldehydes during beer
production and storage and anti-staling effects of the hop dosage [Doctoral thesis]. Inst.
Lebensmitteltechnologie und Lebensmittelchemie.
154. Wietstock, P. C., Kunz, T., & Methner, F.-J. (2016). Relevance of Oxygen for the Formation of
Strecker Aldehydes during Beer Production and Storage. Journal of Agricultural and Food Chemistry,
64(42), 8035–8044. https://doi.org/10.1021/acs.jafc.6b03502
155. Wietstock, P. C., Kunz, T., Waterkamp, H., & Methner, F.-J. (2015). Uptake and Release of Ca, Cu,
Fe, Mg, and Zn during Beer Production. Journal of the American Society of Brewing Chemists, 73(2),
179–184. https://doi.org/10.1094/ASBCJ-2015-0402-01
156. Wietstock, P., Kunz, T., Perreira, F., & Methner, F.-J. (2016). Metal Chelation Behavior of Hop Acids
in Buffered Model Systems. BrewingScience, 69.
157. Yang, F., Luan, B., Sun, Z., Yang, C., Yu, Z., & Li, X. (2017). Application of chitooligosaccharides
as antioxidants in beer to improve the flavour stability by protecting against beer staling during storage.
Biotechnology Letters, 39(2), 305–310. https://doi.org/10.1007/s10529-016-2248-3
158. Yang, L., Lu, Z., Lu, J., & Wu, D. (2023). Evaluation of the antioxidant characteristics of craft beer
with green tea. Journal of Food Science, 88(2), 625–637. https://doi.org/10.1111/1750-3841.16441
159. Yin, H., Deng, Y., Zhao, J., Zhang, L., Yu, J., & Deng, Y. (2021). Improving Oxidative Stability and
Sensory Properties of Ale Beer by Enrichment with Dried Red Raspberries ( Rubus idaeus L.). Journal
of the American Society of Brewing Chemists, 79(4), 370–377.
https://doi.org/10.1080/03610470.2020.1864801
160. Younis, O. S., & Stewart, G. G. (1999). Effect of Malt Wort, Very-High-Gravity Malt Wort, and Very-
High-Gravity Adjunct Wort on Volatile Production in Saccharomyces Cerevisiae. Journal of the
American Society of Brewing Chemists, 57(2), 39–45. https://doi.org/10.1094/ASBCJ-57-0039
161. Yu, J., Huang, S., Dong, J., Fan, W., Huang, S., Liu, J., Chang, Z., Tian, Y., Hao, J., & Hu, S. (2014).
The influence of LOX-less barley malt on the flavour stability of wort and beer. Journal of the Institute
of Brewing, 120(2), 93–98. https://doi.org/10.1002/jib.122
162. Yu, Z., Luo, Q., Xiao, L., Sun, Y., Li, R., Sun, Z., & Li, X. (2019). Beer‐spoilage characteristics of
Staphylococcus xylosus newly isolated from craft beer and its potential to influence beer quality. Food
Science & Nutrition, 7(12), 3950–3957. https://doi.org/10.1002/fsn3.1256
163. Zhao, X., Yu, Z., Wang, T., Guo, X., Luan, J., Sun, Y., & Li, X. (2016). The use of
chitooligosaccharide in beer brewing for protection against beer-spoilage bacteria and its influence on
beer performance. Biotechnology Letters, 38(4), 629–635. https://doi.org/10.1007/s10529-015-2013-
z
164. Zufall, C., & Tyrell, Th. (2008). The Influence of Heavy Metal Ions on Beer Flavour Stability. Journal
of the Institute of Brewing, 114(2), 134–142. https://doi.org/10.1002/j.2050-0416.2008.tb00318.x