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A few questions about chemical acid reduction with potassium carbonate

I have a few questions about how to use potassium carbonate or bicarbonate to reduce acidity.

1) I read about the method of neutralizing all the acid in a portion of the batch and then mixing that with the rest. The purpose is (I think) to neutralize tartaric and some malic acid instead of only tartaric, because malic will be neutralized only when all the tartatic is gone. The question is: does this technique also apply to pottasium carbonate or is it only for calcium carbonate?

2) After you add pottasium carbonate you need to chill the wine. How long do you need to chill it for? One day, one month?

3) How cold does it need to get?

4) After the wine has been chilled and the tartrate salt has dropped to the bottom, do you need to rack the wine while it's still cold so that the salt doesn't get back in solution, or does the salt stay there even if the wine warms back up?

5) Other than adding the pottasium carbonate, chilling, and racking, is there anything else that needs to be done or is the process complete at that point?

Thanks in advance.

Reply to
Franco
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Oh, I forgot. One other question:

7) If this process produces CO2, then after the chilling and the racking do you need to bulk age the wine for several more months so that the CO2 will come out?
Reply to
Franco

It's funny- I'm just about to do this with one of my wines to experiment with where I like the acidity after a MLF. If I may quote Bill Frazier (and my apologies-)

If your wine has too much acid you can raise the pH by getting rid of some of the acid. Try a good, hard cold conditioning first to drop some tartaric. This may get the pH up a little. If you've already cold conditioned the wine you can add K bicarbonate. Adding 0.9 grams/liter will lower acid by 0.1% or 1.0 gram/liter. I do this sometimes. There is no correlation between acid removed and pH increase. I calculate how much acid I want to neutralize (A Cab would be nice with about 0.6% acid). I weigh the required amount of K bicarbonate. I stick a pH probe in the wine (this is done in a large, open vat because there is a lot of foam produced). I add the K bicarbonate slowly, with gentle mixing, keeping my eye on pH. I may not need to add all the K bicarbonate I weighed. K bitartrate is produced in this reaction. It's best to cold condition the wine after to precipitate out excess K bitartrate. This completes the acid lowering process. You will notice a "salty" taste in the wine immediately after treatment but this fades with time.

The crystals should stay solid- they don't readily re-dissolve- at least I've kept mine from last year as seeds with liquid on them and they're still around :)

Reply to
purduephotog

The double salt method is used with calcium carbonate, I have never heard of using it with potassium bicarbonate. You want to get it as cold as possible. 25 F is what I shoot for. If you can't get that cold it will just take longer. I usually chill it for 2 to 3 weeks, if you use some potassium bitartrate as seed crystals you can reduce that time. If you do that you need to stir it a few times.

If you rack cold don't splash, wine picks up oxygen better at cold temps. You can let it warm up, very little if any acid will be reabsorbed.

You should degas by stirring.

Joe

Reply to
Joe Sallustio

Thanks Joe. Are you a home or commercial winemaker?

Reply to
Franco

Home. My background is measurement and control so I read a lot and approach things technically.

Aren't you in Texas? I'm working in Amarillo right now if you are anywhere near there. (Not that anything is near anything in Texas... )

Joe

Reply to
Joe Sallustio

Haha, you are right. I live in Austin, which is "only" 500 miles from Amarillo.

Reply to
Franco

Great town, Austin. We have a robot there too at Seton, I've been there.

You will fix this. More often than not the wine I thought was awful turned out to be the best of that year because i fiddled with it.

Joe

Reply to
Joe Sallustio

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