Science topic
Oenology - Science topic
Oenology are sensory analysis of wine
Questions related to Oenology
Does the winemaking industry currently use enzymes derived from genetically modified organisms?
Hi there!
I would love to hear opinions or experiences about the recommended temperature for grape juice and wine storage.
I need to store juice and wine samples for further chemical analyses (Somers assay, Solid Phase Extraction separation, HPLC for monomers and mDp).
The samples will be stored for about 6 to 12 months, so I'm concern about the stability of the compound during this period of time.
There are opinions about store the samples at -20 Celsius will compromise the compounds stability, so for this reason it's necessary to store everything at -80 C.
Contrary to this, there are many others of the opinion to store the samples at -20 C it's good enough.
What is your opinion? Can you recommend some papers about temperature storage and stability of organic compounds?
Thanks!
Hi there!
I would love to hear opinions or experiences about the recommended temperature for grape juice and wine storage.
I need to store juice and wine samples for further chemical analyses (Somers assay, Solid Phase Extraction separation, HPLC for monomers and mDp).
The samples will be stored for about 6 to 12 months, so I'm concern about the stability of the compound during this period of time.
There are opinions about store the samples at -20 Celsius will compromise the compounds stability, so for this reason it's necessary to store everything at -80 C.
Contrary to this, there are many others of the opinion to store the samples at -20 C it's good enough.
What is your opinion? Can you recommend some papers about temperature storage and stability of organic compounds?
Thanks!
Could a total SO2 level of 12mg/L be the cause of reduction occurring in my wine?
Thank you
Is it possible to restart a stuck secondary fermentation of sparkling wine? What remedies are there?
The base wines underwent malolactic fermentation, some of which did not fully complete it (approximately 60% of the wines). The wines were blended and then bottled ahead of secondary fermentation. How much SO2 would it be advisable to add at tirage to prevent malolactic fermentation from restarting?
Thank you.
Hello, how much SO2 you need highly depend from pH of your wine.
Higher pH higher amount of SO2 you need. SO2 is more active at low pH values.
pH -3.2 - 3.3 - 50 mg/l SO2
pH - 2.8 - 15mg/l SO2
If pH 3.5 or more you need about 100mg/l because most part of SO2 in this pH value acting with other substances in wine.
See attached picture for more info.
Good luck!
Is there any newer and more efficient or accurate equipment for measuring the Brix and pH of grape berries than a digital refractometer (Brix) and a pH meter (pH)?
Dear Erik, I suppose it is a good idea and a good way to try to remove ochratoxin A in swine, as weel as in wine! (Maybe proposing a glass of wine to the swine coud do the job too, however thats is not a serious proposal for the next research :)
Hi! I have a list of wine monoterpenes that I want to dose in wine in various concentrations, from 0,2 to 400 μg/L. A liqui/liquid extraction is necessary? Do you have any preparation protocols?
Thanks for your answer!
I have already made some trials based on the protocol of Segarra and al. (1995) which involves the following;
(1) 1mL of sample + 5 mL EtOH 96% v/v + 50uL HCL (1N) and store for 22 hours at ambiant temperature
(2) spin the samples at 10 000 rpm for 10 min
(3) remove the supernatant and wash the pellet 3 times with ethanol 96% v/v
(4) Dry the pellet
(5) Dissolve the pellet in water.
This method did not give me proper results.
I observed a partial precipitation which is undesirable.
I repeated the method but this time I replaced EtOH by Isopropanol. The precipitation seemed to be much better but now my problem is that after drying the samples in the last step some of the samples still have some colour which would not suit well the following Dubois method which I have to follow . While some samples had color, some others did not dissolve completely and had a sizeable precipitate in water.
A point to note is that all the samples which had precipitate after dissolving in water were the must samples and on the whole wine samples fared better in this method compared to must samples.
I would be grateful if someone could shed some light on my problem and suggest an alternate if possible or a reason to these observations.
Thank for your help
Most oak research, looks at short-term levels of oak derived compounds (ie Eugenol, Vanillin, Oak lactones). I can't seem to find a study that goes anything beyond 2 years in bottle.
I am particularly interested in what their contribution is to mature bottle aged aroma.
Need some reference about the hydrogen peroxide scavenging of wine.
Thank
I am interested in linking firms in resource and waste sharing in order to improve the production system.
I am looking to buy an instrument for pressing the juice out of grape samples of small size (up to 1 kg of grapes). As the pressure applies to the grape samples can affect the extraction of the compounds I want to measure, I am looking for tools with pressure control so to be able to standardize the pressing among samples. Any suggestion of suitable instruments? thanks!
What should be the perfect sensory score and biochemical parameters for a best quality wine?
Methodology for sensory evaluation of wine.
