Sensory Analysis of Full Immersion Coffee: Q&A with Peter Giuliano and Lead Author Mackenzie Batali
Coffee Science Foundation Executive Director Peter Giuliano sat down with Dr. Mackenzie Batali, lead author of a recent milestone study, “Sensory Analysis of Full Immersion Coffee: Cold Brew Is More Floral, and Less Bitter, Sour, and Rubbery Than Hot Brew.” They discuss questions such as these: How does cold-brewed coffee differ from hot-brewed coffee? Are the differences chemical, sensory, or both? And how can our industry develop guidelines and best practices for excellent cold-brewed coffee?
This article is useful for anyone wanting to brew or market cold coffee, on both a small and a large scale.
Access the article free with an SCA Portal account (choose Associate Member).
Impact of Beverage Temperature on Consumer Preferences for Black Coffee
Researchers William D. Ristenpart, Andrew R. Cotter, and Jean-Xavier Guinard of the UC Davis Coffee Center published an open-access research article in Scientific Reports (2022), reporting results from CSF-funded research into consumer preferences for the temperature of black coffee.
Drawing on more than 3,000 tastings, they identified the temperature range most consumers find acceptable and the minimum first-sip temperature at which almost nobody finds the coffee too cold. They also compared how much temperature affected liking relative to other attributes such as flavor intensity and acidity.
The scientific findings are useful for anyone setting brewing, holding, and serving practices in cafés.
Read the full article on nature.com
Amped Up: Using Electricity to Detect and Quantify Molecules in Brewed Coffee
Christopher H. Hendon shares the electrochemistry theory that underpins the Coffee Science Foundation research project, supported by Simonelli Group, toward deepening our understanding of espresso extraction. When we think of coffee brewing, we think of water contacting solid coffee particles. Temperature, brew time, brew ratio, pressure, and all the other variables allow us to modify flavor. Electrochemistry offers us a way to “probe” which molecules have been extracted, how many there are, and how they’re affected by different variables such as brew time.
This article is useful for researchers and anyone keen to understand innovation in coffee science.
Access the article free with an SCA Portal account (choose Associate Member).
Not Just Fresh: Expanding Our Concept of Functional Packaging
Watch the full session from Re:co 2022 on SCA News
As home coffee consumption continues to increase even as pandemic restrictions ease, so too has our interest in understanding packaging (an element of the coffee experience making its way consistently into the home) through a multimodal lens. Dr. Fabiana Carvalho introduces an ongoing study, conducted in collaboration with the Coffee Science Foundation, exploring the effect of packaging on the perception of specialty coffee and explains why we need to expand our concept of "functional" packaging beyond simply keeping coffee fresh.
Sensory Analysis of Full Immersion Coffee: Cold Brew Is More Floral, and Less Bitter, Sour, and Rubbery Than Hot Brew
Researchers from the UC Davis Coffee Center share findings from research into the characteristics of cold brew compared with chilled hot brew in the journal Foods. They investigated the common claim that cold brew is sweeter or less acidic than hot brew coffee and performed a systematic study of how extraction temperature affects the sensory qualities of full-immersion coffee. They also considered interactions with other attributes such as coffee origin and roast.
This article is useful for anyone wanting to make scientifically grounded decisions about how they prepare cold coffee, with a focus on how brew temperature can be used to modulate flavor profile.
Read the full academic paper in Foods.
How Strong is the Coffee You’re Cupping? New Model Captures the Equilibrium Extraction Nature of Full Immersion Brewing
Jiexin Liang, Ka Chun Chan, and Professor William D. Ristenpart of the UC Davis Coffee Center share findings from CSF-funded research into full-immersion brewing in the SCA journal 25.
Their 2022 article presents a model that predicts how strong a full-immersion brew will be once it settles (its equilibrium strength) and how much of the coffee dissolves. The researchers tested the model in 99 experiments plus cupping trials across several roast levels.
The findings are useful for cuppers and anyone brewing by immersion, such as with a French press, siphon, or cold brew.
Access the article free with an SCA Portal account (choose Associate Member).
Roast level and brew temperature significantly affect the color of brewed coffee
Sara E. Yeager and a research team from UC Davis published an article on how roast level and brew temperature affect the color of brewed coffee in the Journal of Food Science in 2022. This research was supported by the CSF with underwriting from Toddy. The researchers tested coffees from three different origins, roasted to three different levels and brewed at three different temperatures, to determine how much impact each variable had on beverage color.
Their research is particularly relevant to those retailing coffee in transparent vessels or wanting to manipulate beverage color to match consumer preferences.
Read the full academic paper in the Journal of Food Science.
How Hot is Hot Enough? Brew Temperature, Sensory Profile, and Consumer Acceptance of Brewed Coffee
Andrew R. Cotter of the UC Davis Coffee Center summarizes CSF-funded research into consumer preferences for black brewed coffee in a plain-language article for 25 (issue 15, 2021). The research asked whether brew temperature itself changes how coffee tastes or whether it matters because it affects strength (TDS) and extraction.
A trained panel and a group of 118 consumers tasted one coffee brewed 27 different ways, and the researchers analyzed their assessments to see how strength, extraction, and brew temperature interacted and affected flavor and liking.
The findings are useful to anyone creating recipes for brewed coffee. Access the article free with an SCA Portal account (choose Associate Member).
Manipulating and Measuring a Key Attribute in Drip Brew Coffee
Dr. Mackenzie Batali summarizes CSF-funded research into acidity in black drip coffee in a plain-language article for 25 (issue 15, 2021). The research investigated whether pH level and titratable acidity can predict perceived sourness. The researchers also tracked how brew strength (TDS) and extraction affect these measurements and perceived sourness.
The article is useful for roasters, baristas, and quality-control teams who want a practical way to measure and adjust acidity, and for cafés serving customers who have different preferences around acidity.
Access the article free with an SCA Portal account (choose Associate Member).
Acids in coffee: A review of sensory measurements and metaanalysis of chemical composition
Sara E. Yeager, Mackenzie E. Batali, Jean-Xavier Guinard, and William D. Ristenpart of the UC Davis Coffee Center published a paper in Critical Reviews in Food Science and Nutrition in 2021. They gathered and analyzed the available literature on coffee acid composition, with a focus on the organic and chlorogenic acids that contribute to sensory properties.
Their review covered studies on both Coffea arabica and Coffea canephora, drawing from 129 publications and over 8,000 discrete data points. Their findings indicate interesting interactions between roast level, acid concentration, and sensory profile.
This article is useful to roasters, quality-control professionals, and anyone trying to understand how roasting can affect measurable acids and sensory properties.
Read the full academic paper in Critical Reviews in Food Science and Nutrition.
Take Part In an Online Study About Coffee Packaging and Flavor Perception
Up for participating in some science? The University of Campinas, Brazil and the Coffee Science Foundation are looking for participants for new multisensory research.
Titratable Acidity, Perceived Sourness, and Liking of Acidity in Drip Brewed Coffee
Dr. Mackenzie Batali, Andrew R. Cotter, Dr. Scott C. Frost, Professor William D. Ristenpart, and Professor Jean-Xavier Guinard of the UC Davis Coffee Center published a peer-reviewed research article in ACS Food Science & Technology (2021), reporting CSF-funded research into acidity in black drip coffee. The research investigated whether pH and titratable acidity can predict perceived sourness and consumer liking across a wide range of brew strengths and extraction yields, three roast levels, and three brew temperatures.
The article is useful for roasters, baristas, and quality-control teams who want to measure and control acidity, and for cafés serving customers who have different preferences around acidity.
An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee
Jiexin Liang, Ka Chun Chan, and Professor William D. Ristenpart of UC Davis published an open-access research article in Scientific Reports (March 2021), reporting research funded by the CSF. The research built a model to predict the TDS and extraction yield of a brew once it reaches equilibrium strength. The researchers tested the predictive model against lab brews and traditional cupping.
This article is useful for cuppers and brewers who want to gain a thorough scientific understanding of full-immersion brewing.
Read the full academic publication in Scientific Reports.
Consumer Preferences for Black Coffee are Spread Over a Wide Range of Brew Strengths and Extraction Yields
Andrew R. Cotter, Dr. Mackenzie Batali, Professor William D. Ristenpart, and Professor Jean-Xavier Guinard of the UC Davis Coffee Center published a peer-reviewed research article in the Journal of Food Science (2021). They studied how TDS, extraction yield, and brew temperature affected consumer preference. Using preference-mapping techniques, they identified clusters of consumers with varying preferences and suggested that the Coffee Brewing Control Chart should be updated to reflect consumer preference segmentation.
The article is valuable for those wanting to adjust brewing styles to suit consumer preferences, as well as for trainers.
Towards a New Brewing Chart
Dr. Scott Frost, Mackenzie Batali, Professor Jean-Xavier Guinard, and Professor William D. Ristenpart of the UC Davis Coffee Center summarize CSF-funded research toward an updated Coffee Brewing Control Chart in a plain-language article for 25 (issue 13). The research asked how flavor changes with brew strength (TDS) and extraction, going beyond the classic chart’s few broad labels, such as “bitter” and “underdeveloped.”
The article is useful for baristas, trainers, café owners, and anyone who manipulates brew recipes to achieve flavor outcomes or match consumer preferences.
Access the article free with an SCA Portal account (choose Associate Member).
University of Oregon in Eugene Awarded Grant for New Espresso Brewing Control Chart
The Specialty Coffee Association (SCA) has chosen the University of Oregon in Eugene for a four-year espresso extraction research project, supported by the Simonelli Group, "Towards a Deeper Understanding of Espresso Extraction."
SCA and Savor Brands Partner on Two-Year Research About Packaging and Flavor Perception
The Specialty Coffee Association (SCA) announces new research partnership with Savor Brands about packaging and flavor perception. The project is slated to run for two years and is aimed at understanding how packaging affects and influences consumers’ perceptions of specialty coffee quality, attributes, and value.
Brew Temperature, at Fixed Brew Strength and Extraction, has Little Impact on the Sensory Profile of Drip Brew Coffee
Dr. Mackenzie E. Batali, Professor William D. Ristenpart, and Professor Jean-Xavier Guinard of UC Davis published an open-access research article in Scientific Reports (October 2020), reporting SCA-funded research into how brew temperature affects the flavor of black drip coffee. The research investigated the presumption of an “optimal brew temperature” and tested whether brewing water temperature changed how coffee tastes on its own or only because it affected strength (TDS) and extraction.
The article is useful for baristas, World Coffee Competitions competitors, café operators, and brewer manufacturers, as it helps to establish how relevant brew temperature is to sensory outcomes.
Effects of brew strength, brew yield, and roast on the sensory quality of drip brewed coffee
Dr. Scott C. Frost, Professor William D. Ristenpart, and Professor Jean-Xavier Guinard of the UC Davis Coffee Center published a peer-reviewed research article in the Journal of Food Science (2020), reporting CSF-funded research into the flavor of black drip coffee. The research investigated how brew strength (TDS) and extraction affect coffee’s flavor, going beyond the classic Coffee Brewing Control Chart’s broad labels, such as “bitter” and “underdeveloped.”
The results provide new insight into how to optimize brewing conditions to achieve desired sensory profiles in drip-brewed coffee.
The article is useful to trainers or brewers wanting to develop a scientific understanding of brew variables and sensory profiles. Read the full academic paper in Journal of Food Science.
Sensory and Monosaccharide Analysis of Drip Brew Coffee Fractions Versus Brewing Time
Read the full academic paper in Journal of the Science of Food and Agriculture
The composition of drip brew coffee versus brewing time has been chemically characterized in previous studies, and it is known that the total dissolved solids (TDS) systematically decreases with each fraction during the brew. Little information exists regarding the corresponding sensory attributes versus time, however, and it is unclear how TDS correlates with flavor profile.
The results of the sensory analysis and the monosaccharide analysis suggest that perceptible sweetness in coffee is a consequence of masking effects and/or the presence of sweet‐associated aromas and flavors. The results further suggest that unique flavor profiles could be obtained from the same coffee grounds by judicious combinations of specific fractions. © 2020 Society of Chemical Industry