Consumer's Sensory Evaluation in Relation to the Coffee Grade among College Students

To read the full-text of this research, you can request a copy directly from the authors.


This study aims to understand college students customer's preference and the difference of coffee grade by comparing the result of Q-grader, who was trained professionally and received certification for a sensory evaluation of coffee grade. The results of the chemical analysis of raw coffee and coffee berry show that those of specialty grade had slightly higher, but not significant, water content. Further, the pH of specialty grade coffee was high in coffee beans and after roasting, the commercial grade became high. There was no significant difference between the specialty degree and commercial degree in color before and after roasting. In this study, the panels for the sensory evaluation included 24 university students. The preference of evaluation items of sensory evaluation consist of aroma, acidity, bitterness, astringency, aftertaste, and overall satisfaction. Items for the strength evaluation consist of aroma, acidity and bitterness. The sensory evaluation was expressed by applying a 5 point Likert scale (1: extremely low~5: extremely high). In the sensory evaluation, it was evaluated that specialty grade coffee had strong acidity and commercial grade coffee was strongly bitter. The result of the sensory evaluation shows that female students are sensitive to coffee taste. In the analysis of frequent visit to coffee shop, the not-frequently-use-group rated that specialty grade coffee with higher overall satisfaction than commercial grade coffee in factors such as aroma and acidity. The group which did not prefer Americano coffee rated that specialty grade was higher than commercial grade in all factors except aroma, of which the result is similar to the cupping test.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Immature-black beans (VP) and immature beans (V), known by the Brazilian coffee terminology as ‘café verde-preto’ and ‘café verde’, are defective beans and cause a reduction of the quality of the beverage. Their presence in raw coffee samples is due to a high percentage of immature fruits at harvest. In this study, some of their physico-chemical properties and chemical composition were investigated and compared with non-defective coffee beans (B). B beans were heavier and had higher humidity than VP and V. Although they did not differ with respect to pH, V beans were more acidic (titrable acidity). Sucrose was the main soluble carbohydrate in all samples and its content in B beans was higher than defective beans. Reducing sugars were found at higher concentration in V and B beans. Protein contents increased from VP to B (VP<V<B); however, there was no relationship with free amino acid contents, which were higher in V beans. Qualitative analysis showed that asparagine was the main amino acid in these beans. Denaturing electrophorectic (SDS-PAGE) profiles of proteins did not show qualitative differences among the three coffee types. The contents of 5-caffeoylquinic acid (5CQA) and soluble phenols were also higher in V beans, and their ratio increased from VP to B (VP<V<B). In this order, the reversed-phase high-performance liquid chromatography profile at 280 nm of methanolic extracts prepared similarly showed, in general, a reduction of detected peak areas. Polyphenol oxidase activity was inversely associated with 5CQA contents, V beans showing the lowest activity. Similar caffeine contents were observed in the samples. Total oil content was higher in B beans. In addition, the defective beans were individually mixed with B beans in different proportions and analysed for some constituents. The results showed that, depending on the substance analysed, its content in the B beans is significantly affected. Although the influence of each component of the raw coffee bean that determines beverage quality has never been established, our results show that the presence of defective beans can drastically change the chemical composition of the final product.
Full-text available
Brazilian arabica coffee is classified for trading according to the quality of the beverage obtained after roasting and brewing. In the present study, Brazilian green and roasted coffee beans were investigated for possible correlations between cup quality and the levels of sucrose, caffeine, trigonelline and chlorogenic acids, determined by HPLC analysis. Trigonelline and 3,4-dicaffeoylquinic acid levels in green and roasted coffee correlated strongly with high quality. To a lesser extent, caffeine levels were also associated with good quality. On the other hand, the amount of defective beans, the levels of caffeoylquinic acids (predominantly 5-caffeoyilquinic acid), feruloylquinic acids, and their oxidation products were associated with poor cup quality and with the Rio-off-flavor. The fact that similar correlations between cup quality and chemical attributes were observed in green and light roasted samples – the latter used for coffee cup classification – indicates that chemical analysis of green beans may be used as an additional tool for coffee quality evaluation.
Coffee beans are processed from coffee cherries by either natural, pulped natural, or washing. The aim of the present study was to evaluate the physiochemical and sensory characteristics of espresso coffees processed by different methods. The color of the washed coffee sample presented the highest value of lightness while the natural coffee sample presented the highest value of redness and yellowness. The biggest difference in brewed coffee, whether natural, pulped natural, or washed, was in the TDS content, which was higher in natural coffee and lower in washed coffee. Sensory descriptive analysis and acceptance test for espresso coffee using a 15 cm line scale were carried out by 12 trained panelists. Natural coffee had the highest cherry-like flavor and sweetness taste while washed coffee had the highest citrus flavor and acidity taste. An important attribute of espresso coffee is body, and natural coffee presented strong body while washed coffee presented a low body attribute. In conclusion, significant differences were observed among the three processing methods of green coffee. Pulped natural coffees presented intermediate physiochemical and sensory characteristics compared to washed and natural coffee. Natural coffees are appreciated for their increased body, and washed coffees are appreciated for added citrus flavors and acidity espresso coffee blends.
Arabica coffee has been classified for trading according to the New York Board of Trade (NYBOT) green coffee classification. The aim of the present study is to evaluate the physiochemical and sensorial characteristics of coffees classified by NYBOT as NY2 (specialty coffee), NY3/4 and NY4/5 (commercial coffee). The density of green coffee was higher for the NY2 sample. The amount of total solids in brewed coffee increase as the green coffee grade decreased and the pH levels decreased as the coffee grade decreased. Descriptive analysis using a 15cm line scale was carried out by 12 trained panelists prepared by espresso coffee and consumer preference tests were carried out by 168 consumers. The NY2 sample had the highest fruity, acidity, sweetness and aftertaste characteristics. In addition, green, rio, sour and astringency characteristics increased as the coffee grade decreased. Acceptance of aroma, flavor, taste balance and overall were higher for the NY2 sample. In the consumer preference test, the NY2 and NY4/5 samples had a similar distribution, but consumers between the ages of 20 to 30 who like to drink brewed coffee more than instant coffee preferred the NY2 than sample over the NY3/4 sample. In conclusion, significant differences were observed among the three groups of green coffee classification in all physicochemical and sensory parameters.
Grinding is an indispensible step in preparation of espresso coffee. The purpose of this study was to evaluate physicochemical and sensory characteristics of espresso according to the grinding grades of coffee beans. Specifically, physicochemical characteristics according to the grinding grades of coffee beans were tested based on foam index, persistence of foam, total solids, concentration, extraction yield, pH, viscosity, total soluble solid content and density. With regard to sensory characteristics, QDA were carried out by 10 trained panels. Persistence of foam, total solids, concentration, extraction, pH and viscosity in physicochemical test showed significant differences among the three categories of the samples. In other words, the finer the size of particles was, the higher value was, at the p=0.001 value. Meanwhile, the value of foam index and total soluble solid content to the grinding grades was the highest in 'fine', at the p=0.001 value. Tiger-skin effect in crema, an important attribute for excellent espresso coffee, was perceived by all of the panels in 'fine'. Also, intensity of flavor was perceived as to the strongest in 'fine'. Moreover, 'fine' had the sweetness to balance the acids and bitters. In conclusion, according to the grinding grades, it was identified that there were differences in the physicochemical and sensory characteristics. Furthermore, when the size of particles was 'fine', it brought to the most positive result.
The consumer awareness concerning coffee beverages has increased in Korea. The objective of this study was to optimize the roasting conditions of coffee bean for consumer's attribute. The optimal roasting conditions for Colombian coffee beans were analyzed by using a central composite design with a quadratic polynomial model by response surface methodology (RSM). The experimental conditions for coffee bean roasting were and 7.93~22.07 minutes. The responses of sensory attributes. physicochemical and physical properties were analyzed with RSM. The width. length and height of green beans increased when the beans were roasted. The higher degree of roasting gave the higher pH and solid contents but the lower total acidity and total phenolic compounds. In sensory tests, the roasting temperature and time had a significant effect on the flavor score. The optimum roasting condition of Colombian coffee bean predicted for maximizing the length, width, solid contents, total phenolic compounds and flavor score were 20 minutes at by RSM.
Changes in flavor characteristics of roasted coffee in 6 package models during storage were investigated by GC/MS analysis and sensory evaluation to establish the criteria of the shelf-life of the roasted coffee in three flavor quality-'fresh', 'satisfying' and 'minimally acceptable' levels. In direct headspace method of GC/MS, 47 volatile compounds were analyzed and the light volatile compounds were reduced sharply at initial stage of storage and faster in the package with air. The correlation between % retention of 2,3-butanedione and overall aroma of roasted coffee showed good linear-relation, of which correlation coefficient (R) were from 0.999 to 0.904 depending on package models, indicating that 2,3-butanedione would be an index chemical for evaluating the freshness of roasted coffee. In sensory evaluation of 6 package models during storage, roasted whole beans (RB) and roasted and ground (RG) coffee in air-package were preserved in 'fresh quality' for week, 'satisfying quality' for weeks and 'minimally acceptable quality' for 12 weeks, while roasted whole beans in valve-package and roasted and ground coffees in vacuum-package, nitrogen-package and oxygen absorbent-package were preserved in 'fresh quality' for weeks, 'satisfying quality' for weeks and 'minimally acceptable quality' for 52 weeks. The oxygen absorbent-package was slightly less effective than other three methods.
Arabica coffee is classified for trading according to the New York Board of Trade(NYBOT) green coffee classification. NYBOT's grading system is based on classification derived from a defect count on a 300 g sample. In the present study, green and roasted coffees were investigated for possible correlations between the content of defective beans and sensory characteristics. Sensory evaluation was performed by expert tasters used by the Specialty Coffee Association of America(SCAA) cupping method. For green coffee, the percentage of defective beans increased. as the coffee grade decreased. Black and sour beans were not found in the NY2 grade coffee out of all natural, pulped natural, and washed coffee samples. Sour and insect damage were found in more natural coffee samples as the green coffee grade decreased. Green and broken beans were found in more washed coffee samples as the green coffee grade decreased. Flavor, clean, uniformity, aftertaste, and overall sensory characteristics were significantly different among the NY2, NY3/4 and NY4/5 grade coffee in all natural, pulped natural and washed coffee samples. The natural coffee in the NY2 sample presented the highest body characteristic. The pulped natural coffee in the NY2 sample presented the highest sweetness and balance characteristics. The washed coffee in the NY2 sample presented the highest acidity and flavor characteristics. In conclusion, the percentage of defective beans increased as sensory characteristics decreased.
This study investigated college students' patterns of visiting coffee shops which are formed by students' preferences. This study surveyed 300 college students in Seongnam. The subjects were consisted of 45.2% males and 54.8% females and the average age was 20.8 years. 41.3% of subjects visited coffee shops once or twice a month and 42.4% of subjects visited coffee shops on a random basis. 26.7% of subjects stayed in coffee shops for 1~1.5 hours. The main purpose of going to coffee shops was to enjoy specialty coffee. The subjects' first favorites was coffee with various kinds of syrups and second one was Americano. When the female subjects in Seongnam chose the coffee shops, they focused more on variety factors than the male subjects. The group of subjects who had monthly expenses of less than 400,000 won focused on price factors more than the group of subjects who had monthly expenses more than 400,000 won. Moreover, environmental factors were heavily related to the usage rate and staying time of the coffee shops. Above all, price factors and promotion factors affected subjects' choice of the coffee shops in Seongnam.
IntroductionExtraction Methods Beverage CharacterizationModified Coffee BeveragesReferences
Defective coffee beans are widely known to negatively affect beverage quality. In Brazil, the defective beans represent a population of about 20% of the total coffee production. These defective beans are separated from the non-defective ones prior to commercialization in the international market and are dumped in the Brazilian internal market, thus depreciating the quality of the roasted coffee consumed in Brazil. In order to offer more attractive alternative uses for these beans, an assessment of their physical and chemical attributes is of relevance. In this study, physical attributes, such as bean and bulk densities, bean volume and colour, and also chemical attributes, such as caffeine, trigonelline and chlorogenic acids, were evaluated in defective and non-defective coffee beans, both in the crude and roasted state. With the determined physical and chemical attributes, it was possible to differentiate the types of defective beans, and it was also demonstrated that both black and sour beans roast to a lesser degree than the other types of beans, under the same roasting conditions.
Preference factors in consumer's coffee taste using Q methodology
  • K D Kim
  • C U Heo
Kim KD, Heo CU. 2011. Preference factors in consumer's coffee taste using Q methodology. Korean J Tourism & Hospitality Res 25:145-161
Study on importance and customer satisfaction of coffee-shop type according to the choice attributes perceived by university students: Focused on Daejon
  • G I Byun
  • S Y Lee
  • W J Cho
Byun GI, Lee SY, Cho WJ. 2009. Study on importance and customer satisfaction of coffee-shop type according to the choice attributes perceived by university students: Focused on Daejon. J East Asian Soc Dietary Life 15:287-295
The World Encyclopaedia of Coffee
  • M Banks
  • C Mcfadden
  • C Atkinson
Banks M, McFadden C, Atkinson C. 1999. The World Encyclopaedia of Coffee. London: Anness Publishing Limited. pp.256
  • A W Smith
Smith AW. 1985. Coffee. Volume 1: Chemistry. London: Elsevier Appplied Science. pp.1-41
The Coffee Cupper's Handbook
  • T R Lingle
Lingle TR. 2011. The Coffee Cupper's Handbook. 4th edition. SCAA. pp.20-39
SCAA Protocols: Grading Green Coffee
  • Scaa
SCAA. 2009a. SCAA Protocols: Grading Green Coffee. pp.1-2
SCAA Protocals: Cupping Specialty Coffee
  • Scaa
SCAA. 2009b. SCAA Protocals: Cupping Specialty Coffee. pp. 1-7
Arabica Green Coffee Defect Handbook
  • Scaa
SCAA. 2010. Arabica Green Coffee Defect Handbook. pp.1-2
Coffee Facts and Statistics
  • Scaa
SCAA. 2012. Coffee Facts and Statistics, pp.1-2