Hey dude, that wine stinks!

I vividly remember the first Château Pradeaux I tasted. This mourvèdre-based red from the region of Bandol in France's Provence had the distinct odour of a horse-filled barn. When I served the wine to a friend, he looked up, smiling, and pronounced his judgement: "This smells like s--t."

But he drank his glass, as did I, and once the initial shock wore off, we both kept going back for more. We even planned a Bandol party, replete with steaks, shiitake mushrooms and lots of smelly blue cheese. Call it "sado-aroma-masochism." While for some people wines such as my bottle of Pradeaux may be considered "aromatically challenged," these aromas have become a quality in a wine that I appreciate more and more. But what makes a wine, made with grapes, smell like a saddle, or a mushroom, or a horse-filled barn?

People, meet Brett

This is not an easy question to answer; even experts are not clear as to how these odours find their way into a wine. Some say it's the way the wine was vinified, others say it's because of vineyard sites, others will talk about temperature and ripeness. But we will focus this discussion on the most controversial suspect - a wild yeast nicknamed Brett.

Its real name is Brettanomyces. The single-celled fungus is found in old barrels, in the chais where they make the wine, and, in some regions, on the grapes themselves. While it is not clearly understood how it enters the wine, or whether the odours found in a wine are even a result of high levels of Brett, the smell is very particular. It's perhaps best described as a sweaty saddle, or even a horse; if you get a whiff of this in your wine, there is a good chance that you have some Brett in there.

While this may sound a bit gross, there is a debate as to whether or not this yeast in fact spoils a wine. Many people actually appreciate small levels of this aroma in their wines, and some of the most sought-after and reputable wines in the world are known for their "Brettiness." These include many expensive Bordeaux, Burgundies, Côtes du Rhône, Bandols and Riojas.

I recently toured an Internet tasting board where an older vintage of a famous Châteauneuf du Pape, made by Beaucastel, was reviewed. I was amazed by the difference of opinions on the wine. For some, it was the model of complexity and elegance, while for others, the more animalistic nature of the bouquet was a turnoff. The people on this board seemed to be serious wine collectors, so this is not simply a case of more educated palettes vs. the uninitiated.

Another case in point: Last week I was at a tasting of the latest wines to hit the shelves of your local SAQ, and at my table were a number of local wine critics. One of the wines, a Spanish blend of tempranillo and cabernet sauvignon from Vallformosa, became the subject of some discussion (you can read my review in this week's suggestions). The first bottle was decidedly stinky, and we asked for a second bottle to be opened, which was pretty much like the first. While a couple of the tasters had that "yuck" look on their faces, I wrote "nice and stinky" in my notes. "Must be old barrels," remarked Jean Aubry from Le Devoir (and he was right). Jean and I just shrugged our shoulders at one another. I assume he liked the wine as well, but I'll let him cast his own judgment.

Brett likes the heat

There are a number of theories as to why Brett decides to show itself in certain wines, and sometimes just in certain vintages. What is known is that it's found more often in red wines than whites, and often in wines that have relatively low acidity. This usually means riper grapes, so it is not surprising that it is usually associated with hotter grape-growing regions.

It is also possible that certain grapes are more prone to Brett infection than others. Mourvèdre, which is the most planted grape in Bandol and is also a primary component in Beaucastel, is often associated with these aromas. Tempranillo, the main grape of Rioja, also can show saddle-type aromas. I have also tasted a number of merlot-based wines that have made me wonder whether there was Brett present.

One of the comments I have heard of the 2005 Bordeaux vintage, a year that was extremely warm, is that the merlot-based wines have shown a certain amount of Brettiness. In her appraisal of the vintage, wine writer Jancis Robinson wrote, "With acidity levels notably low, especially in many of the riper merlots, the Brettanomyces yeast was another threat. On quite a number of wines I smelled a telltale trace of sweaty animal hide."

This theory was backed up by Bordeaux winemaker Jean-Pierre Amoreau of Château le Puy. I have tasted a number of his wines, and the '03 was decidedly gamey. Amoreau told me that when his merlot grapes became over-ripe, a different yeast strain came into play. While he wouldn't use the word Brett, I am assuming that is what he meant.

Kill Brett?

Marc Perrin refused to acknowledge that his Beaucastel owes its aromatics to Brett infection, saying that it is the "terroir." There is an association of Brett infection with poor sanitary practices in winemaking facilities. While this may be true in certain cases, especially in older cellars with lots of old barrels, there is another possible reason for why many more wines don't have these odours.

One thing that Château le Puy and Beaucastel have in common is organic farming practices in the fields and a commitment to using fewer sulphites in their winemaking. Because the Brett yeast thrives only when there are sugars and other "nutrients" left over in the wine after it is vinified, winemakers who choose to add less sulphur, which is used to kill any remaining organisms in the wine, risk creating a Brett-friendly environment.

Aside from sulphur additions, many winemakers practice a technique called sterile filtration, which also eliminates any micro-organisms still alive in the wine. One of those organisms is Brett. The problem with this is that many winemakers believe it strips a wine of its nuance.

The end result is that if a winemaker strives for a more "natural" wine, he or she must be willing to live with the possibility of Brett. This leads to the question: Is Brett a natural part of wine or is its presence a defect, like too much oxygen (oxidized) or high levels of TCA (cork taint)?

The answer is, well, it depends. For those winemakers and consumers who want their wine to taste of fruit and oak, and only that, Brett is an uninvited guest. However, there are probably as many who believe it adds complexity and in small doses can make a wine better.

A Californian winemaker once told me that if he could harness and control Brett, he would love to have small amounts in some of his wines. But in the end, the risk of having it run uncontrolled was too much, and therefore he chooses to eliminate it totally.