Brett or Reduction, Can You Tell The Difference?

[Larry_P]

A related question - I’ve often heard it said that one problem with general market acceptance of Syrah, is its tendency toward reduction. I recently had a winemaker tell me his Syrah always goes into open-top fermenters to try to help offset that tendency. Given that fermenting must is a reductive environment anyway, is there something specific to Syrah which makes it more prone to reduction? Or is it that reduced Syrah is more likely to create off-putting aromas? Or is there a characteristic of the grape that people tend to mistake as reduction?

[Tim_Heaton]

Greg, thank you for that post. I believe I’ve read through it 5 or 6 times now, not because I fail to understand it, but rather because I do. That, and it’s so well written. Thanks again

[thomasP]

@GregT

The problem is that brett and reduction aren’t that simple. You can’t say that brett equals one thing and reduction equals another.

First of all, reduction just means something is not oxidized. But for argument’s sake, let’s say that when we’re talking about wine we’re only talking about sulfur when we talk about reduction.

There are many different types of sulfur compounds and depending on their concentration, the same compounds can even seem to smell different. So there is a range of aromatics that might be caused by reduction. In general, sulfur compounds stink, but they don’t all stink the same way. I think there is somewhere around a hundred different sulfur compounds that have been found in wine - not entirely certain about that though and don’t feel like looking it up at the moment. In any event, there are many and depending on the combination and concentrations, they manifest themselves differently. Some react with oxygen when given air and form larger compounds that aren’t as volatile - that’s what “blowing off” usually is. The sulfur is still there, but as part of a heavier molecule so we don’t smell it as readily.

Without adequate oxygen, nitrogen, and nutrition, yeast will use available sulfur and can make hydrogen sulfide. Plus, some yeasts are more prone to form sulfides than are others. Racking, topping up, filtering, and bottling allow the incorporation of oxygen and help to prevent sulfide formation. The addition of elemental sulfur, either in the vineyard or to the wine, can do just the opposite. But those sulfides don’t blow off with aeration and they aren’t easily oxidized, they simply form disulfides or heavier, less volatile, sulfur compounds for which we have higher sensory thresholds. On the other hand, the lighter sulfides can precipitate with a copper penny, so copper treatment during the winemaking process is used.

Some people don’t think that a little stink is a flaw and in fact, sulfur compounds aren’t always unpleasant - the yeasty or bread-like aromas from aging on lees that one might detect in chardonnay or sparkling wine is also a reductive scent, and the petrol scent of riesling is another, and what I think people sometimes call “mineral” notes in highly acidic whites may be yet another.

And finally, some grapes are more prone to reduction than others. Syrah for example, or Mourvedre. It’s one reason for adding Counoise in the south Rhone, because that grape is prone to oxidation. One of the developments in the south of Spain recently has been the production of Monastrell with careful attention to prevent reduction - it produces wines that are completely different from the stinky wines of yesteryear.

Brett is just as confusing.

it’s all over everything. There’s absolutely no reason to think it’s particularly associated with Chateauneuf du Pape - that’s a huge misunderstanding. It’s associated with all wines around the world, particularly the “peasant” wines. Until recently, CdP was one of those regions. The great influence of Parker on CdP has been cleaning up the winemaking. Same in the North Rhone and in Bordeaux. Same in most of Spain and Italy and certainly in central and eastern Europe.

In the US, UC Davis preached clean winemaking, so brett wasn’t such an issue but that doesn’t mean it can’t be.

With a little oxygen and some nutrients, brett of some strain or another can grow using the alcohol in the wine as a source of carbon, some amino acids in the wine for nitrogen, and even some of the sugars in the wood of the barrels, particularly the toasted woods.

So the wine needs to be able to eat up, or use any available oxygen, so as to deprive the Brett of any ability to grow. Also, Brett grows quickly at temperatures above 60 degrees F, so if you have any in your wine, keeping the wine cold is important. So to the OP’s question about wine age - it can matter quite a bit if brett has been allowed to flourish.

High acidity can inhibit some brett growth. But “modern” wines, with higher pH, higher sugar levels, and in some cases, reduced use of sulfur, all contribute to the growth of brett. So even if the winery is clean, the winemaking style may contribute to brettiness in the wine.

And again, because there are so many strains of brett, and because it manifests itself differently depending on what it is associated with and how concentrated it is, it’s pretty much impossible to say that the absence of a particular aroma is definitive proof of the presence or absence of brett. It can contribute to the bandaid, leathery, smoky, earthy aromas that some wines have, or even some of the buttery notes, or it can be awful.

But because both sulfur compounds and brett can stink, they both can produce what people call a “barnyard” character.

Best explanation for a layman that I have ever read on the issue, Greg.

[john_stimson]

@maureen nelson

Ok so which one was affecting a wine i had last night? On the nose - and lasting the entire 2+ hours it was in my glass - it was incredibly stinky in an earthy/ merde kind of way. On the palate it cleaned up a bit and suggested a beautiful wine was underneath. But the nose remained very offputting to me all night. The wine alongside had a bit of similar stink that blew off. Neither smelled of garlic or smoke.

White or red? sounds like a disulfide to me. there’s a particular flaw in a few whites that I think is a disulfide that to me is like parsnips and marshmallows, without garlic, that never ever blows off and is impervious to copper.

[john_stimson]

I would have said that I don’t have much of a problem telling reduction and brett apart, but when one starts to talk about the origin of smoke in wines and whether it is in some cases a brett characteristic, to me it gets a little confusing. And then what’s the relationship between smoke, and tar, and creosote, and asphalt in wine, or even smoky black olive?

[Mike_de_Lange]

Alan and Greg,

Thanks for the clarifications and I stand at least somewhat corrected. I will try to write a coherent reply once I have caught up on some badly needed sleep.