2009 Pepe Cerasuolo

S

SFJoe

Joe Dougherty
Anyone tried this?

My bottle was so reductive I couldn't drink it. The decanter waits in the fridge, we'll see what happens on another day. But just too much H2S.
 
originally posted by MarkS:
Perhaps you just drank it too young?
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I'm no great expert, but I have a notion that wines that are that far gone in reduction don't age well.
 
originally posted by Ian Fitzsimmons:
So, stupid ridicule-inviting question: what are reductive flavors/aromas like?
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Aromas dominate any flavors IMO but usually they're matchsticky, burnt rubberlike, ashtrayish, those sorts of things.
 
Is the aroma caused by gaseous fermentation products dissolving back into the must, reacting with, perhaps, the S02 routinely used in vinification?

I have a feeling this topic's been hashed out before, so I'll search for prior explanations if it's complicated.
 
originally posted by Ian Fitzsimmons:
Is the aroma caused by gaseous fermentation products dissolving back into the must, reacting with, perhaps, the S02 routinely used in vinification?

I have a feeling this topic's been hashed out before, so I'll search for prior explanations if it's complicated.
Click to expand...

I'm not sure it has. The H2S and other thiols are natural fermentation products, I suppose mostly derived from cysteine and so on. Amount depends on a lot of things--variety, soil, nutrients in fermentation, screwcap or no, etc. etc.

The general solution AFAIK is to catch the problem during elevage and rack the wine, oxidizing the thiols to less smelly things. In extreme cases you can treat with copper.
 
originally posted by SFJoe:
originally posted by Ian Fitzsimmons:
Is the aroma caused by gaseous fermentation products dissolving back into the must, reacting with, perhaps, the S02 routinely used in vinification?

I have a feeling this topic's been hashed out before, so I'll search for prior explanations if it's complicated.
Click to expand...

I'm not sure it has. The H2S and other thiols are natural fermentation products, I suppose mostly derived from cysteine and so on. Amount depends on a lot of things--variety, soil, nutrients in fermentation, screwcap or no, etc. etc.

The general solution AFAIK is to catch the problem during elevage and rack the wine, oxidizing the thiols to less smelly things. In extreme cases you can treat with copper.
Click to expand...

I see no reason to absolve SO2 of involvement in the problem. Some of the H2S could arise from yeasts reducing bisulfite through mechanism or mechanisms unknown. I realize that it's lethal to yeast, but some chemistry can happen before the eventual release from this mortal coil, and enzymatic activity can continue postmortem.

Mark Lipton
 
originally posted by MLipton:
originally posted by SFJoe:
originally posted by Ian Fitzsimmons:
Is the aroma caused by gaseous fermentation products dissolving back into the must, reacting with, perhaps, the S02 routinely used in vinification?

I have a feeling this topic's been hashed out before, so I'll search for prior explanations if it's complicated.
Click to expand...

I'm not sure it has. The H2S and other thiols are natural fermentation products, I suppose mostly derived from cysteine and so on. Amount depends on a lot of things--variety, soil, nutrients in fermentation, screwcap or no, etc. etc.

The general solution AFAIK is to catch the problem during elevage and rack the wine, oxidizing the thiols to less smelly things. In extreme cases you can treat with copper.
Click to expand...

I see no reason to absolve SO2 of involvement in the problem. Some of the H2S could arise from yeasts reducing bisulfite through mechanism or mechanisms unknown. I realize that it's lethal to yeast, but some chemistry can happen before the eventual release from this mortal coil, and enzymatic activity can continue postmortem.
Click to expand...
Agreed.

Though I have certainly had wines that were supposed to have been made without SO2 that were plenty reduced and stinky.
 
Well it is very easy to get rotten eggs reduction aromas without any SO2!
Just make ferment bourbes (gross lees resulting of cold stabulation).

Nasty, really.
 
I've just been doing some research (not very sophisticated) on metabolisms and see H2 shown as a sometimes fermentation product, but not S, hence my surmise that the SO2 is implicated. It looks as the the H2 would be produced by the malo-lactic fermentation, at least for the most part, rather than the alcoholic.

I'd venture a guess that the affect on the wine's aromas results from fermentation in a closed airspace, where, as gaseous H2 concentration accumulates in the confined space above the liquid surface, and its partial pressure builds, outgassing of the H2 generated subsequently is impeded, causing a portion of it to remain dissolved in the solution. So racking would solve it, as you say, if this outline of the process is in the ballpark.

Thanks.
 
I would just like to say that the chemistry explanations from SF Joe and Mark Lipton would be worth the price of admission to this board--if there were a price of admission. I can even almost start to understand what they are saying. That Eric chimes in with winemaker talk is just an extra.
 
originally posted by Brézème:

Well it is very easy to get rotten eggs reduction aromas without any SO2!
Just make ferment bourbes (gross lees resulting of cold stabulation).

Nasty, really.
Click to expand...

Maybe there's some microbial anaerobic respiration in the gross lees, reducing natural sulfides with the organic material and releasing H2S. Mark?
 
Added SO2 can give rise to sulfides in wine. Some producers even add micro amounts of SO2 to a wine's lees to induce small amounts of reduction.

But added SO2 is not the only way to get reduction.
Yeasts fermenting a nutrient poor must can yield sulfides as the microbes break down S-containing amino acids for the nitrogen.
Vineyards treated with elemental sulfur can lead to musts high in S, which can easily become reduced to something volatile and unpleasant.

Many wines get a bit reductive during or after fermentation, even where no SO2 has been added.
Probably the dying complaints of millions of little, stressed-out bugs.
In most cases it is not much of worry... a quick splash and rack can clean things up if needed. Lots of folks like a little reduction for wine in tank or barrel. It's called "noble reduction", and it probably contributes to the complexity of the finished wine. At the very least, it's probably preferable to having your young wine on the other end of the red-ox spectrum.
 
originally posted by Ian Fitzsimmons:
I've just been doing some research (not very sophisticated) on metabolisms and see H2 shown as a sometimes fermentation product, but not S, hence my surmise that the SO2 is implicated. It looks as the the H2 would be produced by the malo-lactic fermentation, at least for the most part, rather than the alcoholic.

I'd venture a guess that the affect on the wine's aromas results from fermentation in a closed airspace, where, as gaseous H2 concentration accumulates in the confined space above the liquid surface, and its partial pressure builds, outgassing of the H2 generated subsequently is impeded, causing a portion of it to remain dissolved in the solution. So racking would solve it, as you say, if this outline of the process is in the ballpark.

Thanks.
Click to expand...
I am perplexed by the production of molecular hydrogen, H2. Do you have a reference?

H2 is explosive across a broader proportion of mixtures with air than just about anything. The Fukushima plant explosions were H2+air, for instance. And to produce it would mean a seriously reductive environment.
 
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