Like Marmite, we might have to agree to disagree when it comes to our own tolerance for wine faults. Either way, love them or hate them, it’s useful to know more about the ‘flaws’ you may encounter, says Natasha Hughes MW
Wine faults: Brettanomyces
‘Great Burgundy,’ Anthony Hanson MW wrote in the 1982 edition of Burgundy, ‘smells of shit. Not always, of course, but frequently there is a smell of decaying matter, vegetable or animal, about them.’ While Pinot Noir rarely smells of faecal matter these days, thankfully, it is entirely possible that at least a part of the aromatic profile that Hanson was referring to was derived from the presence of brettanomyces.
Brettanomyces (or brett, as it’s often known) is a rogue yeast which thrives in wines with low levels of acidity. Wines are particularly vulnerable to brett when the main yeast, Saccharomyces cerevisiae, has died off before fermentation has completely finished, but brett can develop during maturation too – especially when the sulphur dioxide has been used sparingly.
Once brett has established itself in a wine, it produces a cocktail of chemicals that are responsible for its characteristic aromas. Foremost among these are 4-ethylphenol (barnyards, sticking plasters), 4-ethylguiacol (cloves, smoky bacon) and isovaleric acid (sweaty saddles). At high levels, these compounds not only mask a wine’s fruit, they can also leave its finish feeling hard and dry.
Many argue that the presence of a trace of brett can create additional layers of complexity, particularly when the emphasis is on the spicy, smoky bacon end of brett’s aromatic spectrum. ‘As long as brettanomyces is not overly obvious, I think it can add complexity and interest,’ says Steve Webber, the winemaker for De Bortoli in Australia. ‘Personally, I like it in savoury, rustic red wines.’ Generally speaking, though, the presence of brett is less acceptable in delicate Pinot Noir-based wines than it might once have been.