Wine Fault

Tartrate Crystals

Physical

Tartrate crystals are harmless potassium bitartrate or calcium tartrate deposits that form when wine is chilled, appearing as glass-like shards or sediment. They are a physical precipitation — not microbial — but consumers often mistake them for glass or spoilage.

Also known as: Wine diamonds, Potassium bitartrate, Cream of tartar

Typical severity: Low

Cause

Natural tartaric acid salts exceeding solubility when wine temperature drops.

How it occurs

Cold storage, refrigeration, or winter transport lowers solubility and crystals form on corks, bottle walls, or as sediment. Wines not cold-stabilized are more prone.

Prevention

Cold stabilization before bottling to precipitate tartrates in tank, then racking off crystals before final packaging.

Descriptors created

Descriptors reduced

Commonly confused with

Common wine styles

Common grape varieties

Common regions

Related winemaking techniques

Serving implications

Beginner explanation

Those glittery shards in a chilled white are tartrates — safe to drink. Decanting or filtering removes them if appearance matters.

FAQ

Are tartrate crystals glass?
No — they dissolve in warm water and are natural wine acids. They cannot cut glass and are safe to ingest.
Do crystals mean the wine was poorly made?
Not unsafe — but commercial whites are usually cold-stabilized to avoid consumer concern. Crystals indicate incomplete stabilization.

Related ontology entities

See also

Fault identification guidance reflects common wine education practice and may vary by wine style, age, and context.