crystals in wine

Mark,

The crystals are a common phenomenon. They're potassium tartrate, formed from the mineral potassium and the grape acid, tartaric. At warmer temps the compound stays dissolved in the wine, but lowering the temp makes it less soluble and the crystals begin to form. Relax, you've just "cold stabilized" your wine.

Enjoy! Mike MTM

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Thanks for the info. I am happy that it wasn't something that I would have had to pour the wine out for. I have never tried cold stabilizing, I like to ferment my wine out dry. The bottles I have drank didn't seem as dry as it should have been but the ending sg was .997. I put the bottle in the fridge and will open it tonight. Thanks again. Mark

excellent question answers

----- here try this > Mark,

Hi Mark,

Definitely potassium bitartrate (cream of tartar). Welch's juice may have more potassium, not necessarily more tartaric acid. There might also have been less water--either way, the saturation point was reached. This is not a bad reflection on your winemaking or on anything else. The crystals are kind of pretty if you look under magnification.

In any case, the chilling is the right way to get the excess out. Malolactic fermetation reduces malic acid, not tartaric. Cold stabilization by adding chemicals is an iffy business if you're not a chemist. You will from now on be improving your decanting skills with each bottle.

--Irene

Mark,

0.997 is not necessarily dry. The hydrometer reads a little high if the fluid is colder than the calibration temperature of the hydrometer, it may have a bit of residual sugar, it may be the acid is lower, it could be the alcohol is a bit higher. All of those influence the taste.

A better way to check dryness is to use Clinitest tablets to check residual sugar if you want to know that. I doubt you have more that

1.0% with 0.997, probaly less than 0.5%. If that is the case the worst that can happen is the wine will be a little fizzy when it warms up. Regards, Joe