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Sensory Properties and Chemical Composition of Drip Brew Coffee in Relation to Coffee Brewing Parameters.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Sensory Properties and Chemical Composition of Drip Brew Coffee in Relation to Coffee Brewing Parameters./
作者:	Batali, Mackenzie Elizabeth.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	219 p.
附註:	Source: Dissertations Abstracts International, Volume: 82-12, Section: B.
Contained By:	Dissertations Abstracts International82-12B.
標題:	Food science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28262708
ISBN:	9798738650581

Sensory Properties and Chemical Composition of Drip Brew Coffee in Relation to Coffee Brewing Parameters.
Batali, Mackenzie Elizabeth.

Sensory Properties and Chemical Composition of Drip Brew Coffee in Relation to Coffee Brewing Parameters. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 219 p.

Source: Dissertations Abstracts International, Volume: 82-12, Section: B.

Thesis (Ph.D.)--University of California, Davis, 2021.

This item must not be sold to any third party vendors.

There are numerous variables that can impact coffee sensory quality. This research used sensory descriptive analysis and supplemental chemical analysis to determine how variables in coffee brewing can impact the sensory properties of coffee. The overall goal was to systematically quantify how to manipulate brewing variables to achieve specific sensory profiles.The first experiment of this project involved the temporal fractionation of a drip brew. Every 30 seconds, the carafe under the brewer was changed to collect a different increment of the coffee brew, for 8 samples total. Descriptive analysis panelists evaluated all samples and found that the later fractions of the coffee brew increased in sweetness, fruity, honey, and tea/floral flavors. These results correlated with a decrease in total dissolved solids (TDS). However, chemical analysis of the monosaccharide content of all fractions showed that sugars decreased with time and were under the average sensory recognition threshold for all fractions. We therefore concluded that sugars were not responsible for the increase in sweetness, and likely the more perceptible sweet associated aromatics either extracted later or were more perceptible at a lower TDS, leading to an in-crease in perceived sweetness. Secondly, to investigate how brew temperature, TDS, and percent extraction (PE) impacts coffee quality, 27 samples total were brewed to three levels of TDS at 1%, at levels of 1.25%, 1.5% and three levels of percent extraction (PE) at levels of 16%, 20%, 24%, at three different brewing temperatures of 87 °C, 90 °C, and 93 °C. For these 27 TDS-PE-Temperature combinations, the descriptive analysis panel found that temperature had little effect on the sensory proper-ties of drip brew coffee at fixed TDS and PE. The TDS was determined to be the largest driver of difference, though PE made a difference for some key attributes such as sourness and citrus flavor. These results were modeled with Response Surface Methodology to visualize how attributes change within the classic Coffee Brewing Control Chart range. Using the data from the temperature experiment, as well as data collected in a previous collaboration not reported here, the third phase of this project explored the relationship between TDS, PE, titratable acidity, and pH. Titratable acidity was shown in 4 different coffee types to correlate with perceived sourness, and that there is a linear correlation between TDS and titratable acidity. Perceived sourness has a slight negative correlation with PE as well as a positive correlation with TDS. Finally, pH was not shown to have a relationship with extraction variables or perceived sourness.The final stage of the project was investigating the impact of post-brew holding time on the sensory attributes of three different types of coffee in three different types of carafes, comparing external heat input to vacuum insulation over the course of three hours. Despite the measured in-crease in acidity over time both in increasing titratable acidity and decreasing pH, the most substantial change over time is the loss of flavors. It also appears that a carafe with an external heat input is more likely to accelerate the loss of flavor over time. However, the results generally show that coffee flavor remains stable for a longer time than commonly thought, and coffee likely can be held longer than the 30 minutes.Ultimately, this project shows that brewing variables can substantially impact the flavor of the same ground coffee, but that some variables expected by industry to make large differences (brew temperature, post-brew holding time) may not be as important as previously believed. Overall, this work shows that TDS and PE heavily impact the flavor profile of brewed coffee and provides a more systematic guide to brew coffee to a desired sensory profile.

ISBN: 9798738650581Subjects--Topical Terms:

3173303
Food science.
Subjects--Index Terms:

Brewing

Sensory Properties and Chemical Composition of Drip Brew Coffee in Relation to Coffee Brewing Parameters.
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500 $a Source: Dissertations Abstracts International, Volume: 82-12, Section: B.
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506 $a This item must not be sold to any third party vendors.
520 $a There are numerous variables that can impact coffee sensory quality. This research used sensory descriptive analysis and supplemental chemical analysis to determine how variables in coffee brewing can impact the sensory properties of coffee. The overall goal was to systematically quantify how to manipulate brewing variables to achieve specific sensory profiles.The first experiment of this project involved the temporal fractionation of a drip brew. Every 30 seconds, the carafe under the brewer was changed to collect a different increment of the coffee brew, for 8 samples total. Descriptive analysis panelists evaluated all samples and found that the later fractions of the coffee brew increased in sweetness, fruity, honey, and tea/floral flavors. These results correlated with a decrease in total dissolved solids (TDS). However, chemical analysis of the monosaccharide content of all fractions showed that sugars decreased with time and were under the average sensory recognition threshold for all fractions. We therefore concluded that sugars were not responsible for the increase in sweetness, and likely the more perceptible sweet associated aromatics either extracted later or were more perceptible at a lower TDS, leading to an in-crease in perceived sweetness. Secondly, to investigate how brew temperature, TDS, and percent extraction (PE) impacts coffee quality, 27 samples total were brewed to three levels of TDS at 1%, at levels of 1.25%, 1.5% and three levels of percent extraction (PE) at levels of 16%, 20%, 24%, at three different brewing temperatures of 87 °C, 90 °C, and 93 °C. For these 27 TDS-PE-Temperature combinations, the descriptive analysis panel found that temperature had little effect on the sensory proper-ties of drip brew coffee at fixed TDS and PE. The TDS was determined to be the largest driver of difference, though PE made a difference for some key attributes such as sourness and citrus flavor. These results were modeled with Response Surface Methodology to visualize how attributes change within the classic Coffee Brewing Control Chart range. Using the data from the temperature experiment, as well as data collected in a previous collaboration not reported here, the third phase of this project explored the relationship between TDS, PE, titratable acidity, and pH. Titratable acidity was shown in 4 different coffee types to correlate with perceived sourness, and that there is a linear correlation between TDS and titratable acidity. Perceived sourness has a slight negative correlation with PE as well as a positive correlation with TDS. Finally, pH was not shown to have a relationship with extraction variables or perceived sourness.The final stage of the project was investigating the impact of post-brew holding time on the sensory attributes of three different types of coffee in three different types of carafes, comparing external heat input to vacuum insulation over the course of three hours. Despite the measured in-crease in acidity over time both in increasing titratable acidity and decreasing pH, the most substantial change over time is the loss of flavors. It also appears that a carafe with an external heat input is more likely to accelerate the loss of flavor over time. However, the results generally show that coffee flavor remains stable for a longer time than commonly thought, and coffee likely can be held longer than the 30 minutes.Ultimately, this project shows that brewing variables can substantially impact the flavor of the same ground coffee, but that some variables expected by industry to make large differences (brew temperature, post-brew holding time) may not be as important as previously believed. Overall, this work shows that TDS and PE heavily impact the flavor profile of brewed coffee and provides a more systematic guide to brew coffee to a desired sensory profile.
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653 $a Flavor
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710 2 $a University of California, Davis. $b Food Science. $3 3193559
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