Hey winemakers, I have a couple of mildly reduced barrels of '09 pinot. I innoculated with ML about two weeks ago. Cellar’s going to be warmed up soon to get ML going (I’m in a shared facility, so we all go through together). ML may have started, maybe not. Maybe the reduction is due to ML activity, or enhanced by it. My questions:
Do you get reduction during ML?
Do you do anything about it?
What do you do, if anything?
Thanks for your thoughts.
Vincent,
The reduction is most likely do to insufficient nutrients during fermentation. Checking YAN levels at harvest and feeding accordingly will minimize reductive issues. I would just let the wine go through ML, if your barrel room is warmed, and you’ve already pictched the bacteria. Getting a sample sent off to check to see if you have developed heavy duty mercaptans would be wise, as well. More than likely it is a light weight fighter and can be KO’ed with a good airative racking, post ML.
I don’t think I’ve ever correlated reduction to ML. Doesn’t mean there isn’t some causal relationship. Since primary can generate reduction, it does seem to follow that ML could as well - but intuitively it would seem like a less likely vector.
We’re pretty aggressive when it comes to reduction. If we smell it in fermenters we try to get a lot of oxygen into the must when we do punchdowns. If that doesn’t work, we’ll use copper right then. I do taste/smell all our barrels before ML bacteria adds. if I pick up reduction, I’ll usually hit it with a tiny amount of copper. I’ve never coppered during ML, nor would I probably now that I think of it. Following ML we do our one racking of the year - at which point we try to clean up any reduction with splash racking to introduce oxygen, or by doing copper trials. Luckily, we don’t ever have more than a lot or two with issues each year.
Letting reduction go has never been a happy experience for us. Best to get it early when a reasonable amount of oxygen or tiny amounts of copper keep a small problem from becoming a big one.
John, thanks. YAN was fine with both vineyards I worked with, I didn’t add nutrient to anything, ferments were fine. Wines in barrel for a couple weeks were fine, now a couple from one site stink a bit. I stress, a bit. Others working with similar fruit say they have more reduction in theirs, which caused me to go back and check again at this point. They used nutrients, so I’m not sure there’s a correlation here. But I get what you mean. The sulfides are light at this point, but I’ll watch it and get a post-ML analysis to see how heavy duty the sulfides are. Just want to hear from others what they do in this situation, if anything. In case anyone wonders, I let the wines settle for three days before barreling, so going to barrel dirty is not an issue here.
Brian, I don’t necessarily correlate ML and reduction, but I’ve read that some do so it’s on my mind. It does stand to reason that ML might produce reductive components, since primary does. Part of the point of this thread is to see if anyone else sees a correlation, or knows of references to confirm or dispute a connection between ML and reduction.
Vincent; I’ve seen reduction in relation to ml mostly in white and rosé, not usually in red. Brian’s advice sounds good. If you recognize the difference between sulfides and mercaptans by smell,and your diagnosis is sulfide, I’d say a splash/rack after ml, before SO2, might be the ticket, but I haven’t made any Pinot Noir for 20 years, so I’d get a 2nd opinion. No shortage there, I bet.
Steve, I appreciate your input, even if you have no business commenting on pinot noir. 
I tasted through my barrels the other day before routine topping and it turns out there’s only one barrel with maybe a slight stink. Definitely not mercapten, might be oak influence. On reflection, I’m not worried about it at all. I’ll keep my eye on it as I do with every barrel, but I’ve already come to learn the “patience in the cellar” adage. I think I was seeing things that weren’t there. For academic purposes though, this is good discussion, so thanks everyone for your input. Anyone else got thoughts on what to do or not do if reduction shows up before or during ML?
Gusmer in Napa used to sell a cheap sulfide detection kit that enabled you to run trials to distinguish among the various types of sulfides. They probably still have it. According to their literature, it’s fairly important to determine what family your sulfides are in – neither air nor copper are universally appropriate.
Stewart, good to see you here on the board! Looking forward to reading more posts from you.
i left one lot of pinot uninoculated for ml. it was one of two lots with a little reductive note. two different lots picked 7 days apart from same vineyard, but not the same identical wine. the one that has been sitting in barrel not going through ml already cleaned up by itself. the one burbling and in the reductive environment of ml still has some h2s. Experiment was to see effect on tannin structure not h2s but I think the ml because it produces CO2 will tend to keep a wine in a reductive state and prevent h2s from (speculating now) binding with oxidized tannin? or other oxidized compounds and falling out?
Fascinating. I would love to hear how this turns out.
BTW, will the non-ML barrel ever be put through ML?
Best, Jim