What are the crystals on the bottom of the wine?
This is precipitated tartaric acid. It is harmless and is a natural byproduct of fermentation and aging. The crystals that settle out soften the wine and are usually seen after the wine has been kept at cool temperatures for a long period of time. If they are in the fermenting vessels, they should be left behind after racking. If in the bottle, they should be left in the bottle. They are not harmful to drink, but don’t taste good.
