An Analysis of the Acid Profile of Coffee Brews: Caffeine and Chlorogenic Acid Concentrations in Different Forms of Coffee Brew

In this project, different coffee brews were analyzed in order to determine the effects the brewing method had on the final product, particularly the acid profile of the final product. Our hypothesis is that the use of a cold brewing method will produce different amounts of caffeine and chlorogenic acids in the final brewed product compared to traditional hot brewing methods. There are many brewing methods available. For the purposes of this research, three were chosen and one was created. The three chosen methods were: a traditional drip brew, a cold brew, and a Pezzetti espresso brew. The final method was a pour over method and was adapted for the lab. It involved pouring hot water through coffee grounds. High-performance liquid chromatography was the method of choice used to test the amounts of caffeine and chlorogenic acids in each brew. Two separate methods were used, each adapted from their respective DIN (German Institute for Standardization) method. Caffeine and chlorogenic acid solutions were used to create a standard curve for concentrations of both, which in turn was used to determine the concentration of caffeine and chlorogenic acids in the coffee samples. Finally, it was determined that while regular drip and pour over brewing methods produced the most caffeine of the four, the Pezzetti espresso method produced the least. For chlorogenic acids, the cold brewing method produced the highest concentration, while the Pezzetti brew produced the smallest