I keep a refrigerator in our unheated garage for beer and white wine. It has been very cold recently and it has dropped below freezing a few times. My understanding is that the tartaric acid crystals that are sometimes found in wine are formed when the wine gets too cold. Is this the case, are they tartaric crystals, and would two of the same wines, one chilled down to form these crystals, and one stored normally, taste noticeably different?
I just finished a 2018 Walter Scott Freedom Hill Chardonnay that had about a pea size amount of these crystals. The wine tasted great and was not lacking in acidity.
You will not taste a difference. There is a slight - marginal pH shift, but that’s about it. Your wine was also more than likely cold stabilized before bottling. Even with going through the cold stabilization process you generally won’t fully stabilize the wine - just get it to be good enough (especially for the more boutiquey producers - the big boys will stabilize the hell out of a wine).
Last year, I had a BD purchase that shipped in February and, due to FedEx bungling, wound up sitting on a very cold truck for a week.
Wine the wines (all white) arrived, they were loaded with crystals. The producer (appropriately) replaced them at no charge, but assured me that the wines would be fine for near-term drinking, at least. Sure enough, they tasted great and were really not different in any way than the replacements that came a few weeks later.
I have no idea what would have happened if I’d aged them for a decade, but they seemed completely fine, even in that fairly extreme case.
No noticeable difference. Don’t sweat it for one second, unless you end up with the bottle sealed by a layer of crystals! I had that happen a few weeks ago. Once I smashed through the crystal barrier the wine wine perfect.
The tartaric acid probably precipitates out of the wine (turn back to crystals and collects at the bottom) at cold temperature. Wouldn’t it just re-dissolve at normal temperature? Same idea as more sugar dissolving in hot water than cold.
I have not cold stabilized any of my whites and some of them do precipitate slightly when chilled hard. Unfortunately, cold stabilizing wines is a rather expensive endeavor as you need glycol chillers and insulated tanks - and time. You’d have to spend north of $30K just to get in the game and it’s simply not something most smaller wineries can afford to do. There are some additives you can add to the wine that will prevent formation, so this is an option for smaller producers.
I’m myself at a crossroads with this as I make more white wines than when I did when I started. Personally, I don’t care one bit about tartrates in wines I drink, but that’s because I know what they are. In white wines, tartrates can be pretty discerning if you’re not familiar - it can look like little pieces of glass. Anyway, I think, despite my ethos of trying to add as little as possible to my wines, I will have to add this additive to prevent the formation of tartrates. Because having to replace and ship bottles to scared customers who thought they might have drunken shattered glass can really create distrust and add huge costs. Not worth it.
I posted a similar question a while back on another thread, if you read the subsequent posts after, there’s some additional insights into tartrates from people with a better technical understanding than me:
It truly is the ‘lesser of 2 evils’ to me - the tartrates really do not have any negative effect on the taste of the wine; they just don’t ‘look right’ to most consumers. The shift in acidity due to cold stability or using the amino acid - based additives is so minor that it really is a non-issue. You are correct in chilling the wine can be costly - the facility where I make my wines charges more for chilling a single tank that it will cost to use the amino acid additives to multiple wines so my choice is an easy one.
We’ve shifted more and more to not force-cold stabilizing our white wines prior to bottling at Red Newt, on the theory that most of our customers are wine savvy enough to not be put off by the potassium bitartrate crystals. Mind you, for our entry level white wines we still make sure they are cold stable, because the costumer base is different.
Two other things to keep in mind:
Cold Stability is much less ‘binary’ than you would think, it is a spectrum that involves not just a cold temperature, but also temperature over time. You can freeze a wine for a day and still have it throw tartrates after the fact, or you could hold the same wine at 50F for 6 months and have it be ‘stable.’ And even then, someone could get that wine in bottle, hold it at 50F for 6 months + 1 day and suddenly there would be more crystals that hadn’t come out before. Even in-house to test for it, there isn’t a clear cut way to get a straight answer unless you have a fancy conductivity meter and a professional lab set-up. Most of us throw a sample in the freezer for some number of hours or days and then thaw it and see if any precipitate forms. It’s loosey-goosey, to say the least (what temperature is your freezer at, how long did you freeze it for, etc.).
This is overwhelmingly a white wine problem from a consumer-perspective - red wines throw tartrates with some regularity and consumers are much more ok with it (and even take it as a sign the red wine is ‘better’ or ‘more serious’). This is a much larger conversation about biases over red wine versus white wine, but let’s just say this definitely fits the pattern.
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