Analysis of Flavor Characteristics of Cold Brew and Hot Brew Coffee by GC-MS and Consumer Test with Emoticons

In order to study the aroma differences of coffee liquid at different extraction temperatures and the correlation between sensory evaluation and aroma compounds, this study used three types of commercial cold brew coffee and three types of commercial hot brew coffee were used as samples and aroma sensory evaluation was conducted using the check-all-that-apply method based on emoticons. At the same time, the aroma components of the coffee extract were determined using headspace solid-phase microextraction-gas chromatography-mass spectrometry, and the differences in volatile components between cold brew and hot brew coffee were analyzed. The research results showed that a total of 93 volatile components were identified in 6 different coffee extracts, and most of the volatile compounds in cold brew coffee were higher than those in hot brew coffee. In terms of aroma sensory evaluation, the overall preference score of cold brew coffee was higher than that of hot brew coffee. The panelists mainly chose positive emoticons to describe cold brew coffee, while choosing negative emoticons to describe hot brew coffee. Pyrazines, furans, aldehydes, acids, esters, ketones, and alcohol compounds endowed cold brew coffee with a stronger nutty, caramel, sweet, and floral aromas, making it more flavorful. The pyridine, pyrrole, and phenolic compounds in hot brew coffee made it more inclined towards woody, grain, and roasted aromas, with a certain smoky and spicy taste. This study provided data reference for exploring the aroma quality of cold brew and hot brew coffee, and hoped to provide theoretical basis for the research, development, improvement, and application of cold brew and hot brew coffee.