Source of coffee's bitterness identified, could lead to better tasting brew

Bitter taste can ruin a cup of coffee. Now, chemists in Germany and the United States say they have identified the chemicals largely responsible for java ,, s bitterness, a finding that could one day lead to a better tasting brew.

Research by others over the past few years has identified an estimated 25 to 30 compounds that could contribute to the perceived bitterness of coffee. But the main cause of coffee bitterness has been largely unexplored until now, said Thomas Hofmann and colleagues.

"Everybody thinks that caffeine is the main bitter compound in coffee, but that ,, s definitely not the case, Hoffmann said. Only about 15 percent of java ,, s perceived bitterness is due to caffeine, he added, noting that caffeinated and decaffeinated coffee both have similar bitterness qualities.

The researchers found that coffee bitterness is due to two main classes of compounds: chlorogenic acid lactones and phenylindanes, both of which are antioxidants found in roasted coffee beans. The compounds are not present in green (raw) beans, they noted.