Wine tasting opens doors to new dimensions- dimensions of sight, dimensions of smell, dimensions of flavor. But when the aromas start to include bacon and horse manure, you have crossed the line and entered… the Brettanomyces Zone.
This is a journey I made recently with a wine that I have nick-named ‘The Bacon Wine’. It was a 2012 California Zin. The color was a nice red, starting to show a little brick at the edges. Body looked good. I took a sniff, and… BACON! With a hint of band-aid! And then there was the taste, which was completely devoid of fruit. Never have I experienced a stronger example of Brett.
Brettanomyces, commonly called “Brett”, is a naturally occurring yeast that lives on the skin of fruit in the wild. It also happens to like oak a lot, and will grow its way several millimeters into barrel staves. It is a relatively slow growing yeast and is not part of the normal fermentation of wine (that yeast is Saccharomyces). It is also a fairly hardy yeast, and if a winemaker is not careful, Brett will patiently wait its turn, kicking in after primary and malolactic fermentation are complete.
What makes Brett of interest is what it does to the smell and taste of the wine. As it grows, Brett will reduce the natural characteristics of the grapes, things such as floral and fruit notes, and start adding new aromas. These new smells come primarily from four compounds:
4-ethylphenol: Band-aid or leather
4-ethylguaiacol: smokey or medicinal
4-ethylcatechol: savory and meaty
isovaleric acid: blue cheese or smelly sock
How all this works out in the wine depends on a lot of different factors. Some grapes seem to be more affected than others. Some winemaking choices seem to be more susceptible than others. In general, wines go through the following stages as Brett grows:
1) Some loss of fruit and oak character
2) Addition of smoke, leather, and/or spice notes
3) Development of medicinal and barnyard aromas
4) Noticeable loss of mouthfeel and grape characteristics
5) Significant band-aid and horse manure smells
Many people believe that a little bit of Brett influence can improve a wine, giving it a touch of leather, a bit of smoke, a hint of spice. Indeed, it has become part of the signature flavor profile for a number of wines. But go too far, and you get, well, the bacon wine.
Intentional or not, the fact is that Brett is everywhere. Winemakers can’t eliminate it, the best they can hope for is to control it, and there are multiple techniques for doing so. Some can have a profound effect on taste and mouthfeel, such as aging in stainless steel, flash pasteurization, and filtering. Others are more traditional, such as excellence in sanitation, kick-starting fermentations with standardized yeast strains, minimizing residual sugar, and the judicious addition of sulfur dioxide.
You have probably experienced a lot more Brett than you realize. All those times you got an earthy barnyard aroma or a whiff of medicine, it was probably Brett. The growing trend to natural winemaking, which eschews many of the traditional techniques for inhibiting Brett, means we’re probably going to experience more– a development which could lend new meaning to the phrase, “bringing home the bacon.”