Heard of the brett police? If you're an innocent drinker, possibly not. The term will be familiar, by contrast, to European wine professionals who find themselves judging one of Australia's immaculately organised wine competitions. A little "brett" was once typical of certain wine styles (including Australia's own Hunter Valley Shiraz); now it finds itself as welcome as Ned Kelly at cashing-up time. Whether or not this is desirable is a fascinating question. But first, let me explain a little about the microbe on the run.
Brettanomyces, or "brett" in wineryspeak, is a yeast genus. It's not the one responsible for fermenting sweet must or wort into dry, alchoholic wine and beer (that's Saccharomyces), though it does also ferment sugars.
As it does so, it creates a spectrum of volatile fatty acids and volatile phenols. For volatile, read "smellable": a whiff of horse blanket and farmyard. At higher levels, brett can also evoke hospital and bandage scents. At lower levels, the innocent nose may simply note that a particular wine smells smoky, spicy or leathery, which most of us rather like. Analytically, elevated levels of 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) suggest brett has been at work.
Tom Carson, of Australia's Yering Station, is a man of such wide wine culture that I would hesitate to describe him as a policeman but he certainly knows the subject. "Brett is everywhere," he says. "In every tank, hose, pump, barrel, filter, bottling line and anything else that touches wine. All red wines have some 4-EP."
It is, in other words, a fact of wine life - but level is everything. He warns that developing a proficiency at detecting it can be a life-changing experience. "Go home and drink a great bottle of wine," Carson advises. "Because after you get a sensory fix on brett, half the red wine in your cellar will become undrinkable."
Sam Harrop might qualify that. He's a master of wine (MW), consultant and winemaker who wrote his MW thesis on brett in Syrah wines (historically a common partnership, whether in the Hunter or the Rhône valleys: appellations such as Hermitage and Cornas used to be defined by smoke, leather and animal notes).
Harrop staged a controlled blind tasting for his thesis that revealed that only one wine out of the 25 he examined (a Californian Syrah from Edmunds St John) was free of 4-EP and 4-EG; the other samples included top Australian wines such as Henschke's 1996 Hill of Grace and Penfold's 1990 Grange, as well as Jaboulet's 1996 Hermitage la Chapelle and René Rostaing's 1995 Côte Rôtie Côte Blonde. Interestingly, from this quartet, Rostaing's Côte Rôtie had the lowest levels of 4-EP and 4-EG and Hill of Grace the highest. The greatest levels of all in the tasting were found on a 1997 Domaine de Trévallon from Provence. Harrop's conclusion was that "while excessive levels of volatile phenols can have a negative impact on wine quality, lower levels can enhance wine complexity and quality." A little brett, in other words, can be a good thing.
This debate grows ever more interesting when one looks across to the beer world, and widens the frame to include other wine "faults". In the beer world, brett is a treasured and essential component of Belgium's spontaneously fermented lambic and gueuze beers, for example, which explains why two of the main strains of brett are called brettanomyces bruxellensis and brettanomyces lambicus. These are beers with a wine-like acidity, most of which is the consequence of brett, which kicks into action after two to three months and rumbles on until fermentation draws to a close at nine or ten months. The less intense brettanomyces claussenii has, too, been a key element of traditional British stock ales, used for blending London porter.
Avant-garde American microbrewers, such as Tomme Arthur of Pizza Port in Solana Beach or Vinnie Cilurzo of the Russian River Brewing Company in Santa Rosa, now use brett to create their own versions of these unique European styles.
When Alastair Hook, one of Britain's leading microbrewers, wanted to craft a great London porter at his Meantime Brewery in Greenwich, he sent off for his brett by post from White Labs in the USA (www.whitelabs.com).
Sulphur notes (struck match) are regarded as being another dismal fault by most winetasters, yet they are viewed with delight and approbation by Britain's army of real ale enthusiasts, who call it "the Burton snatch". It was a typical note in the classic pale ales for which Burton upon Trent was once renowned, attributable to the use of Burton water drawn from wells that has filtered through deep gypsum beds. Brewers of classic English bitters still often "Burtonise" their water using added mineral salts to give them a snatch.
Even more striking, now that Britain is a lager-drinking nation, is the fact that a "fault" that would send any Australian Chardonnay spinning off the tasting bench to oblivion is actually the principal aroma key for Carling, Britain's top-selling beer. This is a compound called dimethyl sulphide, or DMS (whose sensory trigger is tinned sweetcorn). When I asked Carling's brewing manager, Janet Scott, why more aroma hops weren't used in the Carling recipe, she told me that Carling drinkers wouldn't like it: they prefer DMS. So why do the same drinkers loathe it in their Chardonnay?
They probably don't; it's just they never get the chance to sniff it there. Whether all this cleanliness in today's wines will lead to godliness or acute boredom is a moot point. The construction of great perfumes provides an interesting analogy: mingle heaps of rose, jasmine and violet, and you'll get a cloying mess. Great perfumes have always used elements in them that are individually revolting, like civet, musk, ambergris and oudh. (The first two were original glandular secretions of Chinese wild cats and Tibertan deer respectively, the third is whale vomit while the fourth is based on fungus-infected agar wood.) Such elements add complexity and a kind of visceral sensuality to perfumes, which is exactly what a little brett can do to a great red wine.
In truth, we ought to know better. The wine regarded as a hot contender for the greatest of the 20th century, Cheval Blanc 1947, has levels of volatile acidity (another "fault") that would see it banned from sale were it to be produced today. Sometimes you just have to live dangerously.
