02/10/2023
1 venti iced latte with 4 shots espresso, 4 pumps caramel sauce, 2 pumps vanilla, 5 pumps white mocha, please. ☕
Today, we celebrate the International Coffee Day by delving deep into the chemistry of coffee, more specifically, the Maillard reaction! This chemical phenomenon is responsible for the mesmerizing transformation of raw coffee beans into the delightful roasted beans that fill up our cups and our busy days. From floral to smoky, it's the Maillard reaction that crafts those cherished coffee flavors we adore.
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The Chemistry of Coffee ☕
Coffee is a caffeinated beverage prepared from roasted coffee beans. It may be enjoyed as a stand-alone drink, or as an ingredient in making drinks like iced coffee, cafe au lait, latte, cappuccino, etc [1]. Its flavor is mainly bitter, but other flavors like acidity and smoky notes may also be present in the drink. The signature taste and aroma of coffee comes from how it is roasted. [2][3] Roasting coffee beans changes the chemical components of the coffee beans, aside from preparing it for grinding and brewing. [3]
One of the important chemical reactions that occur during the roasting of coffee beans is the Maillard reaction. Named after Louis Camille Maillard [2], it is a group of reactions responsible for transforming the raw coffee beans into delectable roasted coffee beans. This produces the various notes like floral, chocolate, and earthiness present in the coffee. During this process, the amino group of amino acids and carbonyl group of reducing sugars present in the coffee beans react in the presence of heat [3][4] in order to form unstable glycosylamine which forms various products that makes coffee unique including 2-furfurylthiol [2], which gives coffee its strong coffee aroma and flavor. Depending on the preference of the roaster, it is possible to highlight the various components like acidity or earthiness of the produced coffee [4] by altering the conditions during the Maillard reaction.
[1] Czarniecka-Skubina, E.; Pielak, M.; Sałek, P.; Korzeniowska-Ginter, R.; Owczarek, T. Consumer Choices and Habits Related to Coffee Consumption by Poles. International Journal of Environmental Research and Public Health 2021, 18 (8), 3948. DOI:10.3390/ijerph18083948.
[2] American Chemical Society. Why Does Your Coffee Taste and Smell Delicious?.https://www.acs.org/content/dam/acsorg/pressroom/reactions/infographics/why-does-your-coffee-taste-and-smell-delicious.pdf (accessed 2023-09-20).
[3] Baggenstoss, J.; Poisson, L.; Kaegi, R.; Perren, R.; Escher, F. Coffee Roasting and Aroma Formation: Application of Different Time−temperature Conditions. Journal of Agricultural and Food Chemistry 2008, 56 (14), 5836–5846. DOI:10.1021/jf800327j.
[4] Parliment, T. H. An Overview of Coffee Roasting. ACS Symposium Series 2000, 188–201. DOI:10.1021/bk-2000-0754.ch020.
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Content by Kenneth Maque and Angelo Calaguas
Layout by Louis Barcelino and Aaron Gene Rillas
