Crystals at the bottom of carboy

Winemaking Talk - Winemaking Forum

Help Support Winemaking Talk - Winemaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Senior Member
Oct 22, 2010
Reaction score
While racking my wine today, I noticed a bunch of crystals at the bottom of the carboy, mixed in with the sediment.

What are those, and is that good or bad?
Those are potassium bitartrate, also known as cream of tartar. Around these parts, they are also known as "wine diamonds."

They are neither good nor bad. They are probably more good than bad, as they represent a way of removing excess tartaric acid from the wine.
one way to drop them out is to cold stabilze by putting them in fridge at 28-32*F for about 30 days, rack as soon as you take it out and bottle.
I agree with Doug from Brew and Wine Supply
but I will rack as soon as possible then filter it, if I was going bottle it soon. Then let the wine warm to room temperature prior to bottling after checking ph and acid levels.
I keep a fridge in the garage just for this purpose. Read up on "cold stabilizing". I just pulled a wine after 35 days. I racked it, added a little k-meta, then added my oak. Now for some more aging.