The misunderstood world of Brettanomyces

What’s that pong? LINDA MURPHY examines the much-maligned,misunderstood but, in some quarters, appreciated, world of Brettanomyces.

In the first year of my wine career, I poured wine at a showing of top bottles from around the world. On a break from the stand, I went around the room to taste many of the other offerings.

When I returned to my table, the winemaker next to me asked, ‘Did anything really impress you?’‘The 1989 Châteauneuf-du-Pape from Château de Beaucastel,’ I answered. He chuckled: ‘You must love Brett.’Although I didn’t know what Brett – Brettanomyces (breh-tan-uh-MYE-sees) – was at the time, I adored the Beaucastel’s earthy, leathery, smoked bacon and spice character, fleshy fruit and firm structure.

I would later learn that Brett, a naturally occurring yeast that is not harmful to consume yet can do both good and bad things to the aromas and flavours of wine,would be a hot topic among winemakers, with no clear winner in the debate.

Vintners call it the ‘B word’ and, at best, Brettanomyces can give wine what many believe to be positive attributes that add complexity and depth: earthy flavours of glove leather, smoked meat, bacon fat, tobacco, truffle, clove and other savoury spices.

Yet when B turns bad, it can give wine the offensive stink of barnyard, manure, plasters, wet dog, sweaty horse blanket, mouse droppings and antiseptic. Fearing the latter, many winemakers around the world do everything they can to prevent Brett contamination.

Others encourage a little bit of it, for that extra ounce of interest, yet have to work hard so that the wild yeast doesn’t overwhelm varietal character and fruitiness. Others, well, let’s just say that if cleanliness is next to godliness, some winemakers aren’t going to church. Those who claim goût de terroir for their unsavoury bottlings are merely making excuses for unsanitary practices.

Friend or foe?

There are multiple strains of – and theories about – Brettanomyces, and a full discussion requires a microbiology thesis. Most simply, there are two wine-altering compounds identified with Brett: 4-ethyl guaiacol (4-eg), which contributes what are thought by many to bacon and spice; and 4-ethyl phenol 4-ep), with its negative plasters, wet dog and medicinal characteristics.

Brett can occur naturally in the vineyard and winery, and those familiar with Old World reds from Bordeaux, the Rhône Valley, Rioja, Piedmont and some Burgundy, appreciate the leathery, earthy notes, usually attributing them to terroir – the soils, climate and other growing conditions of the vineyard.Brett shows up in New World wines too, from Australia, New Zealand, Washington State, California and elsewhere, and wines from South Africa have been thumped in the UK press for burnt rubber notes, thought by some to be linked to Brett.

Adam Lee, owner/winemaker of Pinot Noir producer Siduri Wines in Sonoma County, is a badge-wearing member of the Brett police and believes that it obliterates terroir. ‘As a consumer and winemaker, I am not a fan of Brett because it takes away from the wine’s reflection of the terroir,’ he says.

Pinot Noir producer Siduri Wines in ‘Brett from the Rhône Valley tastes essentially the same as Brett from Barossa and Brett from Paso Robles. One of my main reasons for drinking wine is to taste that reflection of place, and I’m tremendously disappointed when this is compromised by Brett. We do everything we can to avoid having Brett in our facility and in our wines, and thus far we have been very fortunate. I’m just not a fan of Brett, whether it’s a lot or a little. It’s like someone saying they’re a little bit pregnant.’

Sensitive subject

Brett shows itself after the fermentation of red wine when it’s ageing in barrel. It loves very ripe grapes, residual sugar, warm fermentations, high alcohol levels, high pH and low acidity. It’s unusual to find Brett in whites because of their higher acidities and lower pH levels.

For reds made in this fashionable, and opulent style, filtration can remove Brett, yet non-interventionist winemakers abhor filtering, for it also removes manygood things in wine, making it less natural.

They also shun any additions of the preservative sulphur dioxide (SO2) which can also knock down this persistent yeast. Yet Brett is everywhere, even in clean wineries. It’s in the vineyard and on the grapes.

It can be in oak barrels and foudres, both old and new (it feasts on the sugar in the wood), hoses, pumps, the bottling line and on the soles of workers’ shoes. Fermentations using native yeasts are said to encourage Brett growth, and an infection in one barrel can spread through cross-contamination.

Brett can rear itssometimes-ugly head in one vintage, and be tame as a bunny the next. It can also be a ticking time bomb, the compounds multiplying in the cellar and in the bottle if the infected wine is not filtered, dosed with SO2 or treated with dimethyl dicarbonate (DMDC), sold under the trade name Velcorin, which is legal – but costly – in the US, yet not talked about outside winemaking circles. Velcorin is a controversial subject, also ripe for a deep scientific discussion.

Bordeaux consultant Denis Dubourdieu says Brett is a fault, but also part of the fabric of Bordeaux. ‘Without a doubt, Brett is seen as a flaw by Bordeaux winemakers,’ he says. ‘It is a matter of great concern to us, as we pick riper berries than ever.

We have to age wines with lower acidity more carefully to keep the genuine fruit complexity. All the classified growths work with selected yeasts in the alcoholic and malolactic fermentations and sulphur their wines better – especially before summer. Or they have a steam machine to clean the barrels.

But to definitively have a Bordeaux without Brett, we’d have to radically change how Bordeaux is made.’ Compounding this challenge is that some people are negatively sensitive to Brett, while others find it inviting.

My threshold is far more tolerant than that of Lees, and I’d hate to miss out on some great wines because they have a touch ofearthy Brett. Peter Gago, chief winemaker for Penfolds in Australia, tells of the issues winemakers face in dealing with Brett: ‘We consider that if it is detectable, then it’s a flaw.

Without wanting to get into detection/recognition thresholds, we think that the argument that Brett adds a touch of complexity has been historically overplayed and misleading. ‘As Brett is not only produced in the vineyard related].

Penfolds has put many procedures in place to control it, remembering that just about all wines contain trace amounts of this yeast. SO2 can be added to grapes prior to crushing; used during maturation and to bottle;and tanks and equipment are thoroughly sanitised on a regular basis.

New and old oak barrels are both guilty landlords.’ Brett is not as prominent in Bordeaux these days, thanks in large part to the work of researcher Pascal Chatonnet. In that one-third had levels of Brett above the perception threshold, and lacked full fruit character and typicity. Winemakers have since cleaned up their collective acts, so to speak, yet a little bit of French wine.

Don’t ask, don’t tell

Rarely will a winemaker (particularly in the US) confess to having Brett in their wines, even when it appears to be present. While vintners might personally appreciate a leathery character in their reds, the Brett Police – winemaking peers and certain critics – will condemn them for what they consider to be evidence of winemaking fault.

It’s a situation reminiscent of the US military’s ‘don’t ask, don’t tell’ position on homosexuality;don’t ask me about Brett, and I won’t have to tell you that it’s in my wine.

As well, wine reviewers can’t declare for sure that a wine has Brett without laboratory analysis to back it up (hence the lack of a ‘Here’s some wines with Brett’ panel in this piece).

An earthy wine can be merely earthy, indicative of the varietal and terroir; the taster next to me might declare the wine compromised by Brett, yet only a lab could prove them correct. Matt Thomson, winemaker for Saint Clair Winery in Marlborough, New Zealand, and an international consultant, believes that in addition to ultraripe grapes and the presence of residual sugar after fermentation, new oak barrels may be responsible for some Brett.

He speculates that harvesting of wood from infected sources may be a source. One thing Thomson knows for sure is that Brett has no place in Pinot Noir. ‘I like a low level of Brett in wines that can take it, but not in Pinot,’ he says.

‘I retaste Pinot Noir barrels at various stages to make sure there is no Brett contamination. Brettcauses a loss of fruit, and it’s such a distraction in Pinot Noir that it erodes the varietal character.

‘Some wines deal with it better – red Bordeaux for example, where it can have a positive role. Chianti can be full of it and it seems to work okay with Sangiovese. Yet Brett can multiply in bottle if the wine is unfiltered and, as it ages, there is a good chance it will bloom, even if just one barrel with Brett was used for the lot.

Most people are working on ways to deal with Brett, even if we do like a bit of it in our Cabernet Sauvignon.’ Perhaps Jean-François Pellett, the Swiss-born winemaker at Pepper Bridge in Walla Walla, Washington, speaks for most winemakers when he says, ‘Brett is something I don’t mind in other people’s wine, I just don’t want it in my own.’

Like just about everything else with wine, whether Brett is positive or negative is up to individual taste. There is no way to tell whether an unopened bottle will have Brett, or whether you’ll detect it and like it – or not. Yet that’s the nature of wine and, who knows, some day the back labels may inform buyers that, ‘this wine has a gentle kiss of sweaty saddle and a touch of Bretty earthiness’.