Cool coffee chemistry

Chemists love drinking coffee—and studying it. The chemistry of hot-brewed coffee is a well-researched niche. With the rising popularity of cold brew, a team of scientists at Thomas Jefferson University were inspired to study the chemical differences between the two beverages. Niny Rao and a team of researchers brewed batches of light, medium, and dark roast coffees at both 100 °C and room temperature. Caffeine content was about the same in coffee brewed at both temperatures. Hot coffee measured higher in both total titratable acidity and total antioxidant content, with the differences becoming more pronounced the darker the roast. Rao hypothesizes that some antioxidants are soluble only at higher temperatures, preventing them from filtering through to the coffee when brewed at room temperature. To find which type of coffee is best for you, Rao suggests going by the data. “If you’re looking for something a little bit low acidity, I would highly recommend a dark, cold brew. If you’re looking for something that has a high antioxidant content, I would say any kind of hot brew,” she says. Because the ACS spring national meeting in Philadelphia was canceled, the team presented its results on SciMeetings, an ACS online platform.