[breht-tan-uh-MI-sees; BREHT] A spoil-age yeast that grows on grapes and in wineries. Because brettanomyces (brett, for short) is almost impossible to eradicate, most winemakers take great pains to avoid it. When it does occur, vintners generally use special filters to reduce the prospect of continued growth in the bottle. Low levels of this pesky yeast can add complexity to a wine's aroma, while overt amounts can ruin it. An organism called dekkera is virtually identical to brettanomyces and produces the same odoriferous results. See also Glossary of Wine Tasting Terms, page 613.

Wine Lover's Companion. Copyright © 2003 by Barron's Educational Series, Inc. All rights reserved.