Is Brett a bad thing? Mmmm….How long is a piece of string? But as a winemaker you should probably have a decent, well informed opinion about Brettanomyces and what it does in wine. I remember as a student going to classes at the Cape Wine Academy in South Africa. We always decided to sit right in the back of the class, because we believed our vocabulary, especially with regards to adjectives, were not sufficient enough to explain why we loved or hated a wine. (And apart from that, we felt quite intimidated by the glares of our fellow classmates should we not agree with some of them…). Luckily I soon realised that it is okay to have a different opinion, because as for the perception of tannin, consumers differ widely in their sensitivity to aromatic substances. Hence, the reason why people differ in opinion when it comes to their perception of a wine and its quality is because of their genetics and not their vocabulary.
Anyway – we’re on Brett. What is it? Apparently also a “probiotic culture”, which will probably make Nicolas Joly shrivel with anguish. I tasted a very highly recommended fruit infused tea the other day. It smelled like the cow shed (the typical old, wet ones) where I learned how to milk cows when I was little. I reflexively read the back label. It contained five different probiotic cultures of which Dekkera anomalaus was one. And I am sure you probably know this, but Dekkera is the anamorph of Brettanomyces. This would be an example of Brett gone badly. Way too much of the pencil shaving, spicy, wet cow yard, funny farmyard, funky, damp hamster cage nuances that can be absorbed and smiled upon by this wine addict.
Five species of Brett are associated with wine, of which B. Bruxellensis is most common. The reason for growth in wine mediums include poor SO2 management (and molecular SO2 influenced directly negatively by a high pH), riper grapes and residual sugars. Too high nitrogen levels in musts (mostly as a function of winemakers who do not regard nitrogen management important) also fuels the action of Brett. What does the spoiled wine taste and smell like? Well, it depends on the aromatic culprit. Three common molecules are responsible for much frustration – 4-ethyl phenol (smells like horse stables, sweatiness, cow yard/barnyard, burnt beans) is the main culprit, IVA or 3-methylbutiric acid (smells rancid, horsy) which is a volatile fatty acid and last, but not least, 4-ethylguiacol (smoky, spicy aromas).
And then, the million dollar question: Can it add to complexity in a wine? I believe yes, particularly if the spicy, smoky 4-EP is present. There is however, opposing opinions amongst scientists and winemakers. Some icon wines have been associated with Bretty nuances. Beaucastel, Henschke, Jaboulet’s La Chapelle and even Penfold’s Grange come to mind and interestingly enough, it is postulated that cultivars such as Shiraz and Mourvedre have more phenolic precursors, thus making it more likely to show Bretty characteristics.
I guess in the end, you should probably ask yourself what you get from Brett, how much of it and how, and whether it contribute to the wine’s typicity and quality.
And ultimately measure your sales, just to make sure you got it right…