Where Did These Floating Things Come From?

Acid Crystals In WineI bottled a batch of strawberry wine which had cleared up perfectly, but then within a couple months, small light colored particles appeared in the bottles. If the bottle is shaken, some of the particles dissolve, but after an hour or two they reappear. The wine tastes great, but with the floating particles, it’s difficult to share it with others. What could the problem be? I have another 6 gallon carboy to bottle in a month, and I hope I can prevent this from happening again. Thanks for your help!
Name: Gary B.
State: PA
It sounds like you have acid precipitating out of your wine. What you are seeing is acid crystallizing and then drop out.
A wine can only hold so much of any one particular fruit acid in solution. What the wine can’t hold will eventually form as crystals in the wine. This is basically what you’ve described. The amount of acid that can be held is affected by temperature. The cooler the wine, the less acid it can hold and the more likely you will experience these acid crystals.
For the wine that you already have bottled, there is not much you can do that wouldn’t involve re-bottling. Since the flavor of the wine is not affected by this particular wine fault, I would not recommend doing anything to it other than enjoy it.
As for the wine you have yet to bottle, I would take a small sample, maybe a pint or a quart, and let it set in the refrigerator for 2 or 3 days. What you are looking for is to see if these crystals will form under such a cold temperature. If no crystals form, then everything is fine for bottling. If you do see crystals, then you best option you have is to chill the entire batch of wine for a week or two. Then rack (siphon) the wine off the acid crystals that form and settle.
This is a process know as cold stabilization. I would suggest that you read over the article, Maintaining Temperature Stability In Your Wine to gain a better understanding of what’s going on here.
What you can do in the future to prevent this from happening is a couple of things:
First is to always use a blend of fruit acids for adjusting the wine’s acidity. This is the reason why we have Acid Blend. By using a blend, no single acid becomes too abundant and more than the wine can keep saturated.
The second thing you can do is using an acid testing kit to know how much Acid Blend to put into the wine. A wine recipe can only make a good guess as to how much fruit acid is needed to bring the wine into balance. But if your fruit is particularly heavy in acid in a given year, the acid called for may be too much. An acid test kit resolves this problem by telling you how much acid is in the wine must before you add any acid. The directions with the kit also tells you what acid level you are looking for and how much Acid Blend you need to add to get there.
I hope this information helps you out . Acid precipitation is an issues that all wineries have to deal with, so don’t feel like Mother Nature is picking on you. The good news is that on your next batch the solution is simple. Cold stabilize if necessary. And, on future batches you can avoid having this problem all together by using and acid test kit instead of following the guestimation called for in a wine recipe.
Happing Winemaking,
Ed Kraus
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.