Can you please explain brettanomyces?

Ask Dr Vinny

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.

Dear Dr. Vinny,

Can you please explain brettanomyces? What does it smell like, and why do you get it in some wines?

—Andrea E., Santa Barbara, Calif.

Dear Andrea,

Brettanomyces, or “brett,” as the cool kids call it, is a yeast, and since it can ruin a wine, it’s generally considered a spoilage yeast. But many wines, including some really terrific ones, have brett in small concentrations. Though brett can occur in white wines, it’s mostly an issue for red wines.

You’ll recognize brett from its barnyard, cow pie, horsey, mousy, pungent, stable, metallic or Band-Aid aromas. At lower concentrations, it can add a spicy, leathery note to a wine, and I think some people like it because it’s easy to pick out, and, well, people like to recognize flavors and aromas in their wines. People’s thresholds of perception (and tolerance) of brett vary—some don’t notice it, while others are more sensitive. It’s controversial to call it an outright flaw, but wines with brett at high concentrations all start to taste the same to me—not good. It’s not a health concern, unless you consider drinking wines that smell like cow pies as detrimental to your mental health.

How does it get into some wines? I’m going to gloss over the microbiology, but quite simply, brett can develop at practically any stage of production. The yeast can be on the grapes themselves, it can be hanging out in a winery, and it can hide in barrels. Since the winemaking process is all about fermentation and yeasts and converting one thing to another, there’s plenty of opportunity for brett to occur. Some winemakers consider a bit of brett as their house style, but for others, once brett takes residence in a cellar, it can be difficult to get rid of.

—Dr. Vinny

Wine Flaws Brettanomyces Ask Dr. Vinny

More In Dr. Vinny

What's the difference between "cooking wine" and regular wine?

Wine Spectator's expert Dr. Vinny explains how cooking wine is made.

Oct 18, 2019

Can a tasting note indicate whether a wine was aged in oak or not?

Wine Spectator's expert Dr. Vinny explains how oak barrel aging influences Chardonnay.

Oct 16, 2019

What effect does wind have on wine grapes?

Wine Spectator's expert Dr. Vinny explains the many ways that wind can influence a vintage.

Oct 14, 2019

Is it OK to freeze wine and drink it later?

Wine Spectator's expert Dr. Vinny explains what happens when wine freezes.

Oct 11, 2019

What's the purpose of the small indentation on the back of a wine bottle, near the base?

Wine Spectator's expert Dr. Vinny explains what a "keyhole" is on a wine bottle, and why …

Oct 9, 2019

What's the difference between DOC and DOCG wines in Italy?

Wine Spectator's expert Dr. Vinny explains Italy's two most prominent government classifica…

Oct 7, 2019
WineRatings+

WineRatings+

Xvalues

Xvalues

Restaurant Search

Restaurant Search