(Eurekalert) - A flavor compound called phenylethyl acetate imparts a hint of rose or honey to wherever it's found -- a dab of perfume, a sip of wine, a slug of beer. Microbiologists in Belgium have used genetic mapping to identify, for the first time, specific yeast genes that produce higher levels of this aroma in alcoholic beverages. The new finding joins other recent work connecting genes to flavors in wines and beers, and may be used to grow yeasts that produce new flavors.

"In some wines, you can smell the rose flavor above all the others," says microbiologist Johan Thevelein at the Center for Microbiology at VIB, a life sciences institute in Flanders. "But why certain yeast strains make more of this compound than other strains, there was no knowledge at all." Thevelein led the study with Maria R. Foulquié-Moreno, also at VIB. Their findings are published this week in mBio.

Yeast plays a critical role in shaping the flavor of a beer: During fermentation, it adds flavors and carbonation. In wine, most of the flavor comes from the grapes themselves, the metabolism of the yeast can alter those flavors, adding secondary flavors. Yeast also contributes its own flavors.