Posted on August 22, 2007 - by deCadmus

Roasted ’til the Bitter End

Science Daily reports that chemists have identified those chemical compounds largely responsible for coffee’s bitterness. More, their findings suggest that most of the bitterness is introduced during coffee roasting.

“Everybody thinks that caffeine is the main bitter compound in coffee, but that’s definitely not the case,” says study leader Thomas Hofmann, Ph.D., a professor of food chemistry and molecular sensory science at the Technical University of Munich in Germany. Only 15 percent of java’s perceived bitterness is due to caffeine, he estimates, noting that caffeinated and decaffeinated coffee both have similar bitterness qualities.

“Roasting is the key factor driving bitter taste in coffee beans. So the stronger you roast the coffee, the more harsh it tends to get…”

This isn’t news to anyone who’s roasted coffee that they know to be exceptional, and ended up with something that could grow hair on a wildebeest’s chest. (And yes, that includes me. Er… as the roaster, not the wildebeest.)

The bit that leaves me scratching my head, however, is this:

“We’ve known for some time that the chlorogenic acid lactones are present in coffee, but their role as a source of bitterness was not known until now,” Hofmann says.

I have a number of books on coffee — books that have been popular references for years — that, I believe, speak at some length to the links between chlorogenic acids and bitterness. Maybe I’m missing something here. Or maybe there’s more to come still from the research.