when to cold stabilize?

Cold stabilization can be done anytime in the process (from what I understand) and I would hold out for colder weather. If it's below freezing it might be advisable to put vodka in the airlocks so they don't freeze. Do rack off when the wine is cold as the tartrates will go back into solution when the wine warms up. HTH

Although some of the bitartrates may precipitate at 40-50oF, you need to get the temperature down to 25-28oF for cold-stabilization. It may also take longer than a week, perhaps even a month. If the outdoor temperature fluctuates by more than 5-10oF, it won't help much. The bitartratres will begin to precipitate as the temperature drops, and begin to re-enter solution as soon as the temperature rises. I would suggest waiting until the temperature is really cold outside, and (after the first night) covering the carboys with some sort of insulating material which will reduce the temperature fluctuations. You can certainly move it outdoors now, but don't expect any significant stabilization until winter.

I live north of Buffalo (NY). When my wine is done fermenting and I'm sure that all sugar has been consumed and that I've racked off a lot of sediment, I bring my carboys up to the garage and leave them in there for a month or so. Even when it's 10 degrees outside, the garage is warm enough not to freeze the wine, but like the other poster, I'd put vodka in the airlocks 'cause the water will freeze sooner than the wine. I rack while it's still cold, so the crystals don't dissolve, then bring back to the basement for some long-term ageing.

If there's any sugar left in the wine, cold stabilization will only deactivate the yeast cells, not kill them, and they may come back to life when brought back to temp. and renew the fermentation. So...I always make sure it's fermented to dryness before cold-stabilizing. I know some people use K-sorbate to halt yeast activity, but I don't like putting it in my wines.

Mark L. Buffalo-Niagara USA

We had icy roads this morninghere in lovely Anchorage, Alaska... I need to stabalize but I need to know at what temperature wine freezes... I suspect our weather may tend to get a bit chilly to leave it out too long.

Later, A.J.

Contrary to earlier advice, I would not rack your wine while cold. Tartrate crystals do not readily redissolve once they have settled out, and racking your wine while cold exponentially increases the oxygen pickup. In our commercial winery we always allow the wine to warm back up to 15degC or so before moving it.

If you want to improve your cold stabilisation, I would suggest adding around 1g/L of cream of tartar once the wine is cold (the kitchen name for potassium bitartrate), then stirring it gently (it actually works best when you stir vigorously, but make sure you avoid oxygen pickup!). Make sure you add the bitartrate through a fine sieve, as the finer the particles, the better it works.

Cheers,

Andrew

i also live north of buffalo! what a coincidence!! i was thinking about the garage also, i assume that even doing that in jan/feb would be ok, putting the carboys in there with some insulation around them???

Andrew says: "If you want to improve your cold stabilisation, I would suggest adding around 1g/L of cream of tartar once the wine is cold (the kitchen name for potassium bitartrate), then stirring it gently (it actually works best when you stir vigorously, but make sure you avoid oxygen pickup!). Make sure you add the bitartrate through a fine sieve, as the finer the particles, the better it works."

How does this work to improve cold stabilization? Whats the action here?

Also, didn't know about the increased oxidizing at lower temps. Thanks for the tips.

The cream of tartar provides a base for crystals to form on... I'm not sure of the more detailed scientific explanation. Regarding the second point, I didn't know that either!

I had no idea, THANKS!!! I'll do that.

Mark L. Buffalo - Niagara USA

Well, that depends on whether your garage is attached or not. I Leave mine in the garage (attached) in Jan./Feb. with no problem, I don't even bother insulating. However, at my old house. my garage was separate from the house, so there was no source of heat coming from anywhere...and you guessed it, I had Pinot Noir popsicle poking out of the end of the carboy one day. Luckily, it was just slushy for the most part, and I salvaged it. Give it a try! (BTW, I'm in Williamsville).

Mark L.

Exactly right. Crystal formation is actually a very difficult process. Crystals begin to form and grow on defects in glass or on an already crystalline particle of the substance. If you have a completely smooth surface, crystals will not precipitate out. Thus, by adding some potassium bitartrate, you are Seeding your wine to initiate crystallization of the bitartrates. The second point perhaps has to do with having a high concentration of fine particles for the crystals to grow on.