Scientific research has indicated that lightly roasted coffee brewed strong is a better antioxidant than green tea, black tea or cocoa. In a paper written several years ago by a group of scientists at the Nestle Research Center 1, the antioxidant capacities of commonly consumed beverages were compared to each other. The group found that the antioxidant capacity of these beverages is coffee > cocoa > green tea > black tea >> herbal tea (the >> means much greater). They also looked at a Colombian Arabica versus an Indonesian Robusta coffee, as well as green coffee versus coffee roasted to varying degrees. When green, the Robusta coffee is a much better antioxidant than the Arabica coffee. When roasted to a light (CTN 110 on the Neuhaus scale) degree, the differences between the two types of coffee disappeared. For the Arabica beans, the light roast retained 78% of the green coffee antioxidant capacity, the medium (CTN 85) roast 56%, and the dark (CTN 60) roast 46%. All of these measurements were taken when the coffee was brewed at a 1.7% “Swiss” concentration. When the coffee was brewed at a 0.7% “American” concentration, the antioxidant capacity was lower, and when brewed at a 2.0% “French” and 2.5% (Turkish?) concentration, the antioxidant capacity was higher.
A couple of interesting things stand out in this study. First, it was run by Nestle, so take it with a grain of salt. They probably sell more coffee (I use that term loosely with their concoctions) than cocoa or tea so the results probably benefit them. But to their benefit they said that they did use “noncommercial” coffee for the roasting test, so at least they just didn’t dump some Nescafe from a container into a test tube of hot water and call it science. Secondly, strength matters. The stronger the coffee is, the more antioxidants it’s going to contain. Also, the roasting process changes the content of the antioxidants in the cup. I’m not sure how the Neuhaus scale relates to the City/Full City/Vienna/French scale, but as the internal bean temperature moves from, say, 350 to 400 to 450 degrees, the polyphenols that make up the majority of coffee antioxidants are going to break down and convert into other less active products. Robusta beans are known to have more of these polyphenols when raw, so that probably makes up the antioxidant difference between the two types of green coffee. Finally, the authors also looked at decaf beans roasted similarly and found that decaf and full caf beans did not differ in their antioxidant capacity, and that adding milk into the coffee also did not change the antioxidant properties of the coffee. So, the take home message is that if you avoid $tarbucking your coffee by keeping the roast reasonably light and don’t skimp on the beans by using a full 7 grams of beans per 5 oz. cup you’ll be better off than your coffee-shunning Chamomile tea-drinking friends.