Cold crash more of a fender bender

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Jul 4, 2023
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Pleasanton, CA
I had a little extra from my 8th batch of plum wine when I transferred from primary to secondary, about a quart. So I thought I might try cold crashing it. It has been in my fridge for a bout a week and it is still definitely fermenting. It has settled out to some degree with an obvious layer of lees on the bottom but still bubbling. The fridge controls are set for 37F but my measured temperature look more like 42F. I guess that just isn't cold enough to stop EC-1118. The SG when I transferred was 1.005. I have close to 40 gallons total and I still need to decide exactly how I want to finish all that. For now, the rest is in secondary.

I would like to really stop the quart in the fridge. I guess I need to rack it and add K-meta and maybe sorbate.
The main purpose of cold crashing AKA cold stabilization is to drop excess tartaric acid in the form of tartrate crystals, reducing overall acidity. This has an effect only if the wine has excess tartaric acid, and if the acid is marginal, you can remove too much acid and make the wine flabby. As you discovered, using cold to stop a ferment does not necessarily work.

For this reason, the recommendation on this forum is to ferment wines to completion, then backsweeten if that is desired.

Sorbate does not stop an active fermentation -- in conjunction with K-meta it acts are birth control for yeast, preventing them from reproducing. If the ferment is slow enough, adding sorbate + K-meta may prevent it from continuing, but that is not guaranteed.
OK thanks for that advice. I saw a video on You Tube called something like "the correct way to stop fermentation" and he basically said to cold crash. I didn't really intend to cold crash the bulk of my 40 gallons. Just isn't feasible. But it was interesting to try it on a small amount just to see what would happen. I do have four gallons in 1 gallon jugs, so I could potentially try cold crashing one of those jugs. Maybe in a few weeks.
I saw a video on You Tube
That's the WMT version of "hold my beer and watch this ..." 🤣

Seriously, while YouTube has a lot of good videos, it's got even more junk. Anyone with a web cam but no clue can record a video on any subject imaginable, which is why YouTube gets a generally poor review on WMT.

If you have question or see/read something, post a question, and you'll get responses from some of the dozens of regulars, all experienced winemakers. The true value of WMT is we cross check and reinforce each other, so advice you'll receive has been vetted by experienced people.
Sure. That's exactly why I posted this one. Forums can be the same way. I am on different forums for a variety of things I am involved with and you can for sure get flat-out-wrong advice on forums. One always has to sift through the replies and over time learn who's replies are generally respected. I have found useful help on many things on YT.

I greatly appreciate your replies.
I'm on a number of tech forums for my work, and was on a few gaming forums. Hard to find rational adults on any of 'em. WMT is very different --- members normally act like adults and we have actual discussions. This is the main reason I spend more online time here than all other places combined. It's been noted that we don't act like the remainder of the net.
* if I wanted to stop a fermentation the fastest way will be to move the container into an ice bath. As you can see air in a fridge has low heat capacity and fermenting wine is exothermic. My question then is what is the next goal?
* if I wanted to completely kill yeast with home based tools I would pasteurize it as 140F for 45 minutes.
* Bryan gave a good description of cold crashing. The dominant acid in plum should be citric. Citric is cold soluble,, example as in soda. It does not cold crash.

What is the endpoint you are hoping to test?
What is the endpoint you are hoping to test?
My goal was nothing very technical. Just wanted to clear some up for early drinking. But, in the back of my mind, I was thinking if it worked well, I might go to greater lengths to cold crash one of my 5 gallon secondaries.

I still want to clear up the quart in my fridge. I don't think I want to heat it. Wouldn't change change the flavor?
As @Rice_Guy said, using ice is the best. If the goal is to maintain residual sugar, rather than back sweetening, it can be done.

I have successfully “cold crashed”multiple roses in ice baths. One at SG 1.012 one at 1.018 (no, I did not create the YouTube video).

In a bucket, add salt to an ice water bath( lots of ice) so it suppresses the freezing point. Usually I can get it less than 30F. Then take your carboy and keep it in the ice bath. Spin the carboy, to create convection in the liquid. I spin for 10 min, then wait about 30 min and spin again for about 10 min a 2nd time. I then keep in the ice bath for another hour or so. This brings to temp down quick and will shock some yeasts into submission. EC-118 may laugh at this process and keep going. I usually use rhone 4600 on my roses. It works on that yeast in my experience. You need to have a fridge that can get down to 32-34F to maintain after taking out of the ice bath.

Depending on the flocculation of the yeast will also determine how fast it clears.