Hot Brew Coffee Has Higher Antioxidant Levels Than Cold Brew

Both avid coffee drinkers, Niny Rao, and Megan Fuller, wondered whether cold brew was any different from hot brew at chemical level. As chemists at Jefferson, they had the tools at hand to find out.

Their study found chemical differences between hot and cold brew coffee that may have health impacts. Drs. Rao and Fuller discovered hot-brewed coffee has higher levels of antioxidants, which are believed to be responsible for some of the health benefits of coffee.

Published in Scientific Reports, the study also found that the pH levels of both hot and cold coffee were similar, ranging from 4.85 to 5.13 for all coffee samples tested. Coffee companies and lifestyle blogs have tended to tout cold brew coffee as being less acidic than hot coffee and thus less likely to cause heartburn or gastrointestinal problems.

While the popularity of cold brew coffee has soared in recent years—the U.S. market grew 580 percent from 2011 to 2016—the researchers found almost no studies on cold brew, which is a no-heat, long-steeping method of preparation. At the same time, there is well-documented research that hot-brewed coffee has some measurable health benefits, including lower risk of some cancers, diabetes and depression.

While the overall pH levels were similar, Fuller and Rao discovered that the hot-brewed coffee method had more total titratable acids, which may be responsible for the hot cup’s higher antioxidant levels.

“Coffee has a lot of antioxidants, and if you drink it in moderation, research shows it can be pretty good for you,” Dr. Fuller says. “We found the hot brew has more antioxidant capacity.”

And considering hot and cold brews have comparable pH levels, Rao says, coffee drinkers should not consider cold brew a “silver bullet” for avoiding gastrointestinal distress.

Fuller and Rao previously had research published in Scientific Reports on the importance of brewing time, roasting temperature and grind size in cold brew coffee.