Calcium Carbonate

Calcium carbonate will not reactivate a stuck fermentation. It may help a fermentation that never got started though (due to pH inhibition of yeast activity) and that is really only seen in fruit wines that use fairly acidic fruits (it happens to me with rhubarb at 6 lbs a gallon and sour cherries).

I would get a similar must going, add fresh yeast. When it is going really strongly take some of your stuck wine add it to the new starter to temper it a bit. Let that go for a few hours at least then add the fresh yeast back to the stuck batch. That might get it going again enough to finish.

I'm doing a cranberry wine that never really took off. Starting SG was

1.08 and after a month it is only 1.04. So I am assuming that acidity is high (I don't have a test kit). I was going to add the least amount recomended to lower acidity 15% and see if that helps, but it says to add before fermentation. My original question is is it safe to do so after fermentation has already been going awhile? I've already tried your suggestion with some champagne yeast a couple of weeks ago and it had no affect. I slowly added must to the starter over a period of 24 hrs and the starter got going good, but when i added it to the batch it just stalled again.

"Droopy" wrote in news: snipped-for-privacy@u72g2000cwu.googlegroups.com:

It will not hurt the fermentation, as long as you do not bring the pH up above 4 or so.

You really should invest the time and material in a test kit. Below pH

3.2 or so is when yeast start to have a problem with the pH. If you are not below that there is no point in adding calcium carbonate, esp since there is little or no tartaric acid in cranberries to precipitate out. (calcium salts of citric acid are still sour tasting, so using carbonate to treat that will really not help)

Cranbetties do have a bit of sorbate in them, that can inhibit fermentation as well. I would draw off a quart or so of the wine and do a bench trial with the calcium carbonate. Wait for 1-2 days, if it was going to help it would happen in that time span.

Dumpster wrote:

Thx Droopy, I'll give it a shot.

Dumpster ,

Cranberries, like blueberries & some other berries, contain benzoic acid, which is a natural preservative. This often causes slow or stuck fermentations.

Try this: Make a new starter with fresh yeast. When its going strong, add half its volume of your must, and wait 'til its going strong again. Then increase the next must addition to half the current fermenting volume, wait, etc. Add progressively larger volumes this way 'til all of your original must is in the fermenter. It's a little tedious, but it nearly always works.