Wednesday, May 13, 2009

Weird Things About Wine # 61 - Mosel and the Sulfur Stench

So recently I'm at a Wine & Spirits blind tasting called "2007 in Germany," and the strangest thing happens. About halfway through the tasting, when we hit the Mosel, I come to a wine that really reeks of hard boiled eggs. There is one more wine in the flight, and I smell that one too, and it also reeks of sulfur.

I look around the table to see whether or not anyone else seems to have noticed, and I see at least two confused faces. So I ask the critic, "Is something wrong with number 21? And maybe with number 22 also?" And I have that smug feeling like I am so good that I'm going to speak up in front of everyone, that's how sure I am.

But I was, in fact, wrong - there was nothing at all flawed about the wine, even though it reeked. The critic and the tasting director exchanged a quiet word or two, and then the critic said "Do you know about the sulfur smell with Mosel, slate, and native yeasts?" None of us knew, and be honest, did you know about this?

Apparently, wines from the Mosel, when they come from vines on slate soils, and when they are fermented with native yeasts, give off a distinct sulfur stench in their youth. But they develop quite well, the critic assured us. We were encouraged to ignore the smell and taste the wines. I honestly had a hard time doing that. How can you taste a wine when your nasal passages are filled with sulfur stench?
I held my breath and took a sip, and the wine was...excellent. Beautiful clear fruit, elegant, poised, great structure, just a delicious wine. But what about that smell? "It goes away in time,' I was told again.

So let me make sure that I understand this: Riesling from the Mosel, IF it is grown on slate, and IF if is fermented with only its own yeasts, stinks of sulfur in youth, and THEN becomes beautiful? Apparently, the answer is yes. This doesn't happen anywhere else? Or on limestone soils? Or with wines grown on slate but fermented using industrial yeasts? Does it depend on the character of the vintage? No, no, definitely not, and no.

What is the science behind this? And why would they allow this to happen in the Mosel, in this money-rules day and age? Aren't they afraid that consumers will be turned off to their wines, given that they smell like a chicken coop, and that they will lose business?

I tasted many Mosel wines at this tasting, some of which had no sulfur smell at all. But I also tasted eight Mosel Rieslings that reeked of sulfur, and each one was somehow more delicious and compelling than the last. And all of those eight were made by JJ Prüm, the venerable old grandmaster of the region. Eight truly rotten and stinky wines, all of them delicious, and all of them apparently destined for greatness.

And to think, had I purchased and opened a bottle of 2007 JJ Prüm Riesling Mosel Kabinett Wehlener Sonnenuhr, I would have returned it to my retailer, finding it flawed. I wonder how many people do that.

If you can figure out this whole wine thing, then more power to you.


Lars said...

Hi Neil,

J.J. Prüm's wines often smell of sulfur, because relatively higher amounts of sulfur are used and his wine-making is fairly reductive and tends towards the sweeter style. It has little to do with slate or native yeasts or both. His wines are made for the long haul, hence higher sulfur levels. Wines fermented spontaneously, on the other hand, often have a complex smoky/stinky nose, that's termed "sponti," and Prüm's wines have this note, too. Sweeter wines fermented with native yeasts tend to show the "sponti" aromas more often than dry wines, because the fermentation has been arrested, usually by temperature control and sulfur. Yet, many wild-yeast fermented dry-tasting wines have this stinky nose, too, though not always. Many factors play a role. But it's different than the sulfur smell. So, a Mosel Riesling can be "sponti" (i.e. stinky from wild yeasts), but not smelling of bad eggs. I hope this helps.


guilhaume said...

if these wines smell like sulfur it is simply because, like mosts german rieslings, they are over sulfured!
that explanation about the yeasts and the slate definitely sounds like bullshit.If most mosel wines smell like that, it's probably coming from a lack of good vignerons in the region!

Director, Lab Outreach said...

I didn't know any of that. How awesome is Lars?!


Alice said...

Lots of sulfur being used, smells like sulfur. Reduction? That's another thing. Give a good swirl, a good decant? Bingo. Presto. But eggs are...sulfur. When I was in the Mosel, I loved it when people said, I barely use sulfur .......and I started to sneeze. The sneeze is always correct.

Lars said...

Slate clearly plays no role here, but reduction can result from using higher levels of sulfur and it doesn't have to be smelling of rotten eggs. The wine can simply be muted or closed down in bottle. Spontaneous fermentation combined with reductive wine-making (such as pressurized or stainless-steel tanks, early sulfuring, etc.) often accentuates the funky (reductive) smells. Also, Manfred Prüm arguably makes some of the greatest sweet wines on the Mosel despite high sulfur levels. Of course, some tasters are more sensitive to this than others, but the wines keep for decades.

Tista said...

I don't know anything about german wine, but the parametres are interesting.
SO2 does not give off an egg smell, H2S does. Which would suggest that the must received an excessive dose of SO2 before or during fermentation.

I don't think that the indigenous yeast + slate can be put aside as many other factors could produce this aroma; an enzyme accompanying the indigenous yeast strand in the slate vineyards of the Mosel could give a similar aroma to H2S, just like other reductive aromas are often confused with Brettanomyces.

That said, the fact that the wines only have the "egg" aroma when they are young does raise a few questions on SO2.

I'm sure someone more knowledgeable will be able to help us out.

Arjun said...

It is important to distinguish between different sulfur compounds and their different smells.

The most important difference is that between hydrogen sulfide (H2S), which smells like rotten eggs, and SO2 (sulfur dioxide), which smells like burnt match. The burnt match stinkiness of Prum wines is due to large additions of SO2. A wine that smells like rotten eggs, on the other hand, contains H2S (or other sulfides) which is usually indicative of reductive conditions during winemaking. Both of these conditions will dissipate with time.

Finally, as Lars points out, there is a third sort of stink associated with "sponti" fermentations. I do not know how that aroma evolves with time, but Lars probably has some experience.

Lyle Fass said...

It's not just the Mosel. Many Schafer-Frohlich wines show this aroma and Tim says it is redcution and not sulfur.

Director, Lab Outreach said...

I think we should ask Vincent du Vigneaud. He'd know...

Brooklynguy said...

Thanks for all of your thoughtful and interesting comments.

I remember the smell as eggs, or like a natural sulfur hot spring, not as burnt matches. And I also remember that the wines were completely pure and bright on the palate, which was so odd to me given the overwhelming aromas.

I understand that Prum heavily sulfurs at bottling. Does he ferment with natural yeasts? I'm a bit surprised to hear that the slate/natural yeasts idea is not what's driving this.

By the way, check out Arjun's post on 4 days with 2007 Prum W.S. Auslese.

baltimoeronvino said...

This is all very interesting to me, as I have a couple bottles of '01 & '02 Prum Wehlener Spat. cellared, and have also drank a bottle of each in the last year. I love these wines, and appreciate the reductive style very much. Never had any sulfur notes, but the '02 was certainly more closed than the '01.

This is really fantastic commentary as it seems (at least to me) that understanding German Riesling is a never ending quest.

On a side note: Will anyone be attending Rudi Wiest's portfolio tasting in June?

Jon Webster said...

I tasted the 2007 Prum Rielsings from Wehlener Sonnenhur and Graacher Himmelreich last week with Katerina Prum. The Wehleners definitely had a funk to them, though it struck me more as an odd waxy/lanolin/ammonia odor and not really sulfurous. The Graachers were crystal clean on the nose. And yes the stinky Wehleners were delicious. I think we'll see a lot of theories as to the cause of the obvious funk, but no real definitive proof either way, though Katerina alluded to it being a result of the slaty terroir.

Lars said...

Neil: in my previous comments, I mentioned the spontaneous (i.e. wild-yeast) fermentation can often give a funky nose early on. Maybe I was too vague, but yes, Prüm ferments with wild yeasts. It's no real mystery. He also picks late from old vines. The wines often have, besides the "sponti" and sulfur aromas, a prickle that also indicates an air-tight fermentation (pressurized tanks?). I've asked a Mosel grower, who is also a scientist and experimented over the years with various methods, to give us a more precise explanation in regard to the stench.

Peter Liem said...

So as the critic who spawned this whole discussion, I suppose I ought to clarify myself. I didn't say that it was sulfur, I said that it imitated sulfur, because if you've never smelled this particular component before, the smell of sulfur is usually the closest associable thing that you can relate it to. In fact, it is an identifiably and distinctively different smell than either SO2 or H2S—I disagree with brooklynguy that it smells of eggs. It has nothing to do with sulfur, but rather the sponti stink that Lars refers to. It can be accentuated by reduction, but it is not purely a reduction character either. For whatever reason—I'm not a scientist so I can't tell you—it tends to be particularly pronounced in young rieslings from the Mosel-Saar-Ruwer that have been grown on slate and fermented with native yeasts. (Best and most consistent examples are JJ Prüm and Nik Weis.) Unfortunately, the vast majority of people, including most wine professionals, mistake this odor for sulfur, but if you take the time to compare the two, it is easily distinguished.

Lars Carlberg said...

Ulli Stein, who wrote me an email tonight, explains that it's a very complex issue that requires some knowledge of chemistry to properly understand. Instead of writing chemistry formulas, he gives us a simpler explanation. Let me type a rough translation of his text, even if some of the points are already well understood by the readers:

To begin with there are various types of "Böckser" (off smells or tastes) that can arise for different reasons and lead to a taster's overall impression.

One off-smell is hydrogen sulphide (rotten eggs) that can react with other components to form mercaptans that can smell of cabbage, cheese, sweat, leather, burnt rubber, onions, or garlic.

Another off-smell comes from yeasts when a wine rests too long on its lees, i.e. the yeasts die and dissipate.

Both of these faults can take place in the same wine.

Then there are the aroma off-odors that are a result of spontaneous (wild-yeast) fermentation, which can be deemed positively, but when the concentration is too high or combined with other substances can be judged negatively.

Generally speaking, off-odors are much more likely to result with wild than pure culture yeasts, in addition, a long (possibly too long) lees contact, an airtight upbringing (in stainless-steel or high-pressure tanks, plastic, and no wood), and high dosages of sulfur, e.g. to stop fermentation. Cellars also develop their own "internal yeasts," which can also account for off-odors. If this were all happening at J.J. Prüm, then this explains the stench. That is to say the following can contribute to off-odors: molecular sulfur in barrels, spontaneous fermentation, internal yeasts with increased off-odor anaerobiosis, steel or high-pressure tanks, excessive lees contact, high fermentation and maturation temperatures, and high sulfur dosages.

One simple test would be to put in one glass a copper coin, in the other nothing. If after 10 minutes, the wine with the coin, no longer stinks, then it's an off-odor from H2S. If the coin has no influence on the wine, then it's a more complicated fault that is difficult to clear up.

Ulli wrote that the off-odors have nothing to do with individual vineyard sites, soils, or different grape varieties. It's solely a question of the wine-making. If the wine smells of sulfur, then it has a pungent (burnt-match smell), but not stinky. As stated before, it is a complex topic that is perceived differently among individuals. Some tasters find any slight deviances (except pure culture yeasts) in the nose as off-odors, and others rave about stinky aromas as complex.

Director, Lab Outreach said...

Toto, is this UC Davis?

Lars, That is a really interesting, and detailed account. I, for one, really appreciate the effort that went it to getting it, translating it, and then explaining it in a way that I think I get it.

I've enjoyed the whole discussion. I bet Davis isn't nearly this fun!

Thanks to Professor BG as well. Great seminar.

Brooklynguy said...

Hey Lars - this is very thoughtful of you to take the time and effort to leave this, and your other comments. And quite informative too. Thank you! Reading Peter's comment and now this, it makes more sense.

I suspect that in my eagerness to tell this story, and to share this weird thing that I learned about wine (or so I thought), I used language to describe the aromas that probably was not accurate. I remember it as more natural sulfur hot springs than eggs. I wish that you all had been there to smell for yourself. And that coin test would have been fun too.

Thanks again to all for your thoughts - who knew how interesting a little oddness in the aroma of a young Mosel wine could be...

Lars Carlberg said...

You're welcome. It's been a while, but I decided to post an article on my site about this topic.