Cold stabilization

[harmony24]

Can anyone explain what cold stabilization is and how to do it?

 

[ColdClimateWines]

Essentially it is a process used to precipitate tartaric acid from the wine. If you have ever baked you might have used cream of tarter, which is the by product of wine making. To cold stabilize chill your tank, carboy or other container to just above freezing to precipitate the acid crystal out of solution. These crystals, when found in bottles are typically referred to as wine diamonds. They are harmless. For home production, you do not really need to cold precip unless you plan on giving wine away as presents. The crystals are more visible in whites and really are just a visual issue.
Tom

 

[harmony24]

Thanks for the reply. I do give some wine away for presents.

 

[Gr8zins]

I bring my carboys to the garage to achieve the cold stabilization. I just have to make sure that the temperature won't go much below 25 degrees, and to put vodka in the airlocks cause the water will freeze. works great but it is a real pain hauling 20 or so carboys up from my basement then back down.

 

[harmony24]

I still do not understand the benefit. Does it make the wine taste better? Age quicker? Give a different flavor? Won't your carboys break or crack? Last question. Lol. What is the minimum temp for cold stabilization and what is the max?

 

[Gr8zins]

The carboys crackng or breaking have not been a concern for me. I would not recommend going below 25 degrees or so because the alcohol has a lower freezing point than water so will not freeze. Thats why vodka is needed in the air locks instead of water. There can be some expansion in the volume of liquid though.

The main reason that I cold stabilize it to get the suspended tartaric acid to precipitate out of the wine while still in the carboy. It makes little difference in the taste, but it will prevent the crystals from forming in the bottle at a later time, especially for whites which I generally refridgerate

 

[harmony24]

Okay. I understand now. Sorry, I've only been making wine now for about 9 months. Still learning.my wife refrigerated some of my raspberry wine and white crystals were lying on the bottom of the bottle. I just figured I needed to filter my next batches. How long do you leave in the cold?

 

[Gr8zins]

Usually about 10 days or so does the job. I have an insulated garage door so It doesnt get too cold in there. If the long term forecast ls like 30's by day and 20's by night i feel pretty safe. Had a severe cold snap a few years ago where it got to 10 below, and I had the biggest shraz "big gulp" ever made. I was able to save the wine though

 

[ColdClimateWines]

I still do not understand the benefit. Does it make the wine taste better? Age quicker? Give a different flavor? Won't your carboys break or crack? Last question. Lol. What is the minimum temp for cold stabilization and what is the max?

The purpose is really a commercial wine application. Consumers tend be finicky when they see stuff in their wine. C.S reduces the temperature to force these crystals of Tartaric Acid out of solution.

Reds typically do not require it since most reds are stored and served at room temp. White and roses are often refrigerated and most domestic refrigerators are around 41-43 degrees. If you chill the wine e.g. Cold stabilize , below 40 degrees, when someone refrigerates it crystal will not settle because you forced them out of solution already.
But what if your wine is placed in the freezer for a quick chill or an ice bucket to serve. Well then the wine would have its temperature lowered to around 36degrees F. More crystals of acid would precipitate out since you had only C.S. to 40 degrees ( example I used above). To avoid this most wineries chill or Cold Stabilize their wines to around 33-34 degrees F, if they do it at all. Some wineries use caves or cellars to store their bulk wine, especially reds. Temperatures are typically in the low 50's to mid 40's. That is the only C.S. they use.

I do not believe there is a noticeable difference in taste. It might make a sharp wine a little less so. That is an interesting avenue for those of us making cold climate wines, that often are more acidic. Thanks for the thought!

 

[grapeman]

Right you are about lowering the acid a bit ColdClimateWines. Typically this time of year my white wines are stored in one part of the winery where the temps are allowed to drop to almost freezing. Not only does it help drop a bit of acid, it also aids in clearing up slow clearing wines.

 

[GreginND]

Well, I did get a significant amount of tartrates out of my King of the North just sitting at 60 degrees. I put it in my cold room a few days ago at about 30° and there's a lot mor coming out. My Frontenac has a beautiful snowscape of tartrates now as does my MN1200. Those reds were pretty acidic and I never got around to doing MLF on them so I hope they balance out a bit.