Tartrate Crystals

Potassium bitartrate crystallization — a natural, harmless precipitation of tartaric acid salts when wine is chilled below the temperature at which it was stored. More common in unfiltered, unstabilized wines. Technically not a fault, but consumers often mistake crystals for glass or sugar.

Small, clear or whitish crystals at the bottom of the bottle or attached to the cork. In reds, they may appear dark-tinted. Called 'wine diamonds' by producers. Tasteless and odorless — they affect appearance only, not quality or safety.

Cold stabilization (chilling wine to -4°C for 1-2 weeks before bottling). Some producers add metatartaric acid or carboxymethylcellulose (CMC) to inhibit crystallization. Many premium producers skip stabilization, considering crystals a sign of minimal intervention.