Glossary entries

When tartaric acid in wine binds with potassium, it forms potassium bitartrate (cream of tartar) crystals that accumulate on the cork or at the bottom of a bottle. They are harmless, tasteless, and do not detract from the bouquet or flavor of a wine, but unfortunately, they resemble glass shards. Volume producers prefer to avoid the problem altogether via cold stabilization prior to bottling. The wine is chilled to near-freezing temperatures to provoke crystal formation, after which it is transferred to another container, leaving the crystals behind. Decanting is a simple method of separating a wine from the crystals. More about tartaric crystals and how it forms