Calcium carbonate addition preferment

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Just a Member
Aug 19, 2012
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It is too late for the batch I just finished, but better to learn late than to never learn...

I just pressed my blackberry wine, got almost 4 gallons of straight juice from 42# of berries. I adjusted the pH preferment from 2.98 to 3.28 with 2tsp of calcium carbonate. I added the calcium carbonate straight to the bucket. Postferment the pH was back down to 3.03.

So I'm reading about using potassium carbonate post-ferment (haven't decided to do it yet, just reading). I came across one source which states that calcium carbonate preferentially binds tartaric over malic. In order to keep the malic and tartaric balanced, you should add the calcium carbonate to a smaller sample first, then add that sample back to the wine. The site indicates that failure to do this can result in an unbalanced wine with too much malic.

In theory, for fruits that don't have an appreciable amount of malic like blueberries, this technique shouldn't matter much. But of course blackberries have plenty of malic.

My question is, does anyone practice this technique, adding the calcium carbonate to a sample first? Did I screw up my beautiful 4 gallon batch of straight-juice blackberry? Do you have suggestions on handling the pH/acidity at this point?

EDIT: after reading further and thinking this over, I may not have a problem. There really isn't any tartaric in blackberries anyway, so it seems this technique would only be needed really for grapes or other rare fruit that have significant tartaric acid in them. I would welcome other thoughts however on managing the pH of this wine, or whether I'm better off just balancing it by backsweetening (which is what I'm leaning toward anyway).
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