whats the science of cold crashing wine?

[B1GDave]

I've seen it mentioned here and there but other than the beer side of this page, haven't seen too much mentioned here in the wine department. As the title asks, what is the science of cold crashing? As in when do you it? How long does it take? What temperatures are good? Does it work well with fruity wines or all wines for that matter? Any other advantages other than clearing? Any negatives? That should be a good jumping off point
Thanks in advance for the info!

 

[pumpkinman2012]

Cold stabilization a method used to keep tartaric acid crystals from forming after the wine as been bottled.
Normally, we bring our wine down to low 30° for at least 2 weeks, that causes tartaric acid to form tartrate crystals, also known as wine crystals or wine diamonds, excess tartrates will precipitate from the wine. This mellows the wine by reducing the acid.
If wines are not cold stabilized there is a chance that these crystals will form when consumers place bottles of wine in the refrigerator or store it for long periods of time. While the crystals are harmless it can be rather unsettling to find what looks like broken glass in your wine.
I usually do not cold stabilize my reds, but I've found that the carboys aging in my cellar will drop wine diamonds over a period of time even at low 50°.

 

[shelly_belly]

It's done just before bottling.

From "THE HOME WINEMAKERS MANUAL" by Lum Eisenman

Cold Stabilization

Practically all new wine contains excessive quantities of potassium bitartrate, and the tartrate precipitates out
of cold wine as crystals or hazes. All white and blush wines require cold stabilization before bottling, and
most commercial producers cold stabilize their red wines as well. <cut> The wine is cooled to about 27
degrees and held at this low temperature for a week or two until the excess potassium bitartrate
precipitates. This method of cold stabilizing wine also has advantages and disadvantages. Low
temperatures are beneficial to new wine in several ways. Besides causing the potassium bitartrate to
precipitate, the cold temperature helps other unwanted materials settle out of the wine. Sometimes
suspended pectin and gums can be removed by chilling the wine. In addition, several days of low
temperature storage can be helpful in developing long term wine stability.

Edit: pumpkinman2012 beat me to it

The negative would be that unless carefully handled considerable oxygen can be absorbed while the wine is cold causing oxidation.

 

[bernardsmith]

I suspect the question is not so much about how to remove tartaric acid crystals as whether cold crashing (as brewers call it) effectively helps in the removal of the yeast by forcing it to precipitate or flocculate and drop out of suspension and indeed aids in the precipitation of other particulates in the wine.
Certainly when I store excess wine in the fridge the wine seems to clear far more rapidly than the the same wine in carboys left to age in my basement but I am not entirely convinced that cold crashing results in the removal of active yeast such that a single racking from a batch that is cold crashed will not contain sufficient yeast to ferment any addition of sugar if my intention was to back sweeten the wine. I think professional wine makers filter their wine to remove the yeast and I simply use time and multiple rackings to remove enough of the yeast to enable me to stabilize the wine with K-meta and K-sorbate

 

[pumpkinman2012]

Shelly - I usually cold stabilize long before I bottle, I use to follow that rule religiously, but I find that you can cold stabilize at your convenience.
Bernardsmith- Good to see you here, as with beer, cold stabilizing will help a wine to clear faster, I agree, I usually over look this point since this usually isn't my focus when cold stabilizing wine due to the fact that most of the time I use a fining agent for white wine, and let time/aging clear their red wine.

 

[B1GDave]

I just placed my 1st 5gallon batch of strawberry wine in the kegorator.
How does oxidation occur while cold stabilizing?
And before bottling, do you let the carboy sit out overnight too get back to room temp before back sweetining in the bottling bucket? Thanks again!!!

 

[Yooper]

I just placed my 1st 5gallon batch of strawberry wine in the kegorator.
How does oxidation occur while cold stabilizing?
And before bottling, do you let the carboy sit out overnight too get back to room temp before back sweetining in the bottling bucket? Thanks again!!!

Oxidation can occur if there is headspace in the carboy, particularly because the cold 'pulls' in oxygen through the water in the airlock, or worse, sucks up the water from the airlock into the wine due to the temperature change. Removing the airlock and using a solid bung will help with that!

You don't have to warm up the wine before bottling.

Remember that cold stabilization clears the wine quite a bit, but you'll still have to use stabilizing chemicals before sweetening the wine so you'll want to rack to another carboy for stabilization (to get it off of the sediment from the cold period) and then when it's ready to sweeten, sweeten it there. If no fermentation starts up again, then it is ready to bottle.

 

[B1GDave]

Awesome thanks!
When you back sweeten and add the potassium sorbate, how soon would you see (if any) it referment?

 

[Yooper]

You rack off of any lees into a solution of Camden and sorbate. Remember that the wine must be totally clear for this to work and no longer dropping any lees, so it cannot be rushed. Once you rack the clear wine into the stabilizers, wait at least three days (but you can wait much longer). After three days, if the wine is still totally clear, you can sweeten. Wait at least three more days and if no further fermentation occurs and the wine stays clear, you can bottle. But you can wait another month to make sure as I would.

 

[marco5150]

I have bottled early a couple times with very little sediment, but I was lucky to get just a lightly carbonated wine, the judges actually liked it and it made a couple extra points because of it,,, but I have never been able to do it again,,

 

[Lauritsen]

Do you cold crash before or same time as you use fining agents?

Cold stabilization a method used to keep tartaric acid crystals from forming after the wine as been bottled.
Normally, we bring our wine down to low 30° for at least 2 weeks, that causes tartaric acid to form tartrate crystals, also known as wine crystals or wine diamonds, excess tartrates will precipitate from the wine. This mellows the wine by reducing the acid.
If wines are not cold stabilized there is a chance that these crystals will form when consumers place bottles of wine in the refrigerator or store it for long periods of time. While the crystals are harmless it can be rather unsettling to find what looks like broken glass in your wine.
I usually do not cold stabilize my reds, but I've found that the carboys aging in my cellar will drop wine diamonds over a period of time even at low 50°.

 

[theDREWery]

Some fining agents can leave fluffy lees, so I would plan on adding fining agents, letting them work, and then cold crashing. This would allow the tartarite crystals to help compact any fluffy lees.

 

[pumpkinman2012]

I cold crash before I fine, mostly due to the fact that my wine is in my cellar and mother nature takes care of it from there, the low temps and time do all of the work, the "by the book" method is to bring the wine down to low 30° for at least 2 weeks, that causes tartaric acid to form tartrate crystals, also known as wine crystals or wine diamonds, excess tartrates will precipitate from the wine.

I hope that this helps

 

[Lauritsen]

Thanks
So you cold crash and THEN do fining.
Is it still cold when you fine or have you heated it up?
What do you use as fining agent?

I cold crash before I fine, mostly due to the fact that my wine is in my cellar and mother nature takes care of it from there, the low temps and time do all of the work, the "by the book" method is to bring the wine down to low 30° for at least 2 weeks, that causes tartaric acid to form tartrate crystals, also known as wine crystals or wine diamonds, excess tartrates will precipitate from the wine.

I hope that this helps

 

[pumpkinman2012]

You can cold stabilize then fine.
I always let mine warm up to room temp before I fine.
I use sparkolloid, it has worked great for me.