My whole wine world is shaken.

What does Syrah taste like? Are floral aromas pretty? Is a “typical Bordeaux” supposed to taste like medicine and ashes? I don’t know anymore.

I’ve been to a Brettanomyces tasting at UC Davis. I described it on Twitter as spending a day in a room full of laboratory-created stink cells. I couldn’t get the taste out of my mouth for hours.

But the psychological impact … well, I may be scarred for life. As I said at the tasting, “It’s like learning that Darth Vader is my father.”

The seminar was ground-breaking for UC Davis, which previously always called Brettanomyces in wine a “spoilage organism.” This was the first time the university acknowledged that brett is an important part of some wines’ terroir. UC Davis tested 83 strains of Brett and 17 — more than 20% — were regarded as giving more positive impact than negative.

That’s a big deal. Wineries are always looking for some way to boost the deliciousness of their wine. Here is the world’s foremost university on teaching clean winemaking, suddenly saying that Brett — previously derided as the bad yeast that makes your wine smell like rotting corpses — might actually add the scent of roses.

And that’s why I’m wondering whether roses in my wine — something I used to treasure in Gewürztraminer and Riesling, and to enjoy hints of in Pinot Noir and Nebbiolo — are actually the smell of, well, spoilage.

Sac vs Brett

Here’s a brief background on Brett. Saccharomyces (let’s call it “Johnny Sac,” for you Sopranos fans) is the “good” genus of yeast that wineries want to convert sugar in their grapes into alcohol. Brettanomyces, a different genus, is a misshapen cousin. They live in similar environments, which is to say everywhere: in vineyards, barrels, wood ceilings, winery workers’ clothing, etc.

Both types of yeast produce, in addition to alcohol, a variety of chemical compounds. This is one reason wines smell and taste complex, although it must be noted that grapes themselves are loaded with naturally occurring aromatic chemical compounds to begin with.

Saccharomyces — Johnny Sac — grows five times as fast as brett so it will naturally take the lead on almost every wine fermentation. But Brett is more versatile: it can eat different things, including ethanol and amino acids. It’s more tolerant of pH and temperature changes. It’s hard to kill. And everything you might use to kill Brett — usually SO2 — is just as effective at killing Johnny Sac.

This is why commercial wineries blast grapes with sulfur when they’re picked, and then add live Saccharomyces yeast when the sulfur dissipates. All of the work wineries do in controlling fermentation is to keep Johnny Sac healthy and productive, so that brett stays marginalized, because you can’t be sure of having one without the other.

This is also why wineries add SO2 to wines before bottling. If the wine is dry and there’s no sugar left, Johnny Sac won’t come back. But Brett in the bottle will find something to eat and will grow slowly over time. Open that bottle, expose it to air, and brett will come forth and multiply. This is why Bretty wines should never be served by the glass.

The reason wineries want to marginalize Brett is because of its dark side. Remember I wrote that Brett can make a wine smell like rotting corpses? That’s no exaggeration: Brett can produce a compound called “cadaverine.” Brett produces another compound, isovaleric acid, that is the main component of foot odor. And these aren’t even the stinky cells Brett is most famous for: those would be 4-EP and 4-EG, which have been described as “Band Aids” and “ashes.”

Villain or hero?

But like a lot of cinematic villains, Brett has its admirers. Chinese don’t think 4-EP smells like Band-Aids; they think it smells like 5-spice.

Many French winemakers think Brett is part of their terroir and the reason their wines taste as they do, and they’re not alone. Napa winery owner Delia Viader, who has also worked in Italy, says, “I could tell you that the Italians don’t describe Brett as a negative, ever. They actually invite it over for dinner.”

The argument over whether Brett‘s influence can be positive is not new, though UC Davis’ change in position is. But it is UC Davis’ introduction of the new Brettanomyces Impact Wheel that has shaken my world.

There are plenty of nasty aromas on the wheel. But it’s the nice ones that make me wonder what wine actually tastes like.

Here’s what I mean. There’s a section of “spicy” aromas on the wheel; it includes chili powder, red pepper, black pepper, cardamom, and cola.

I thought that’s what Syrah smells like. I thought Syrah can smell gamy, like “horse,” or “leather” or “cooked meat” or “smoked meat.” Those are all descriptors on the Brett Impact Wheel.

And what about Cabernet? I thought that “coffee” and “mocha” and “graphite” were what Cab smells like, and I thought “cigar” came from expensive barrels. Yep, they’re all on the Brett Impact Wheel.

Does terroir trump grape?

It’s a question of the primacy of grape variety, the American way of thinking, vs. terroir, the French way.

What UC Davis is saying is that maybe Rhone wines are supposed to taste peppery because certain Brett strains are a part of the Rhone environment. In a rare concession, UC Davis is saying the French are right.

Moreover, they proved that U.S. consumers have already figured this out. UC Davis professor Linda Bisson went out to buy wines described online by consumers as “typical Bordeaux” and discovered that they were just loaded with 4-EP and 4-EG. So typical Bordeaux, for many people, already equals Brett.

But where does that leave those of us raised to think that grape varieties, not terroir, have a particular taste? I just don’t know anymore what I once thought I did.

Three days after the Brett seminar I tasted some Australian Grenache from century-old vines. Two wineries made different versions: one was riper and fruitier and less interesting. The other was spicy and interesting and just a week earlier, I would have chalked it up to old vines and earlier harvesting. Now I wonder if a misshapen molecule was the source. And I liked this wine better.

Actually it’s worse than Luke Skywalker’s horrible discovery. Of course I’m not going to stop liking the aromas of roses and jasmine and graphite and coffee and smoked meat.

But it’s like waking up in the morning and discovering that … Darth Vader is my lover. Oh Padmé, I know your pain.