Metatartaric acid
Overview
Metatartaric acid is a partial condensation polymer of tartaric acid, formed by controlled heating of tartaric acid. It is used almost exclusively in winemaking, where it prevents the precipitation of calcium tartrate crystals — the harmless but commercially undesirable white crystals sometimes called "wine diamonds" — that can form in bottled wine during cold storage. It functions as a crystal growth inhibitor, keeping tartrates in solution over the wine's commercial shelf life.
JECFA's ADI is 30 mg per kilogram body weight per day, evaluated within the tartrate group ADI established in 1978. After ingestion, metatartaric acid hydrolyses back to tartaric acid, following the same metabolic pathway as E334. No adverse effects specific to metatartaric acid have been identified beyond those of tartaric acid itself.
Metatartaric acid is approved in the EU (winemaking use only) and several wine-producing regions globally. Consumers drinking wine need not be concerned about its presence — the amounts are minimal and the compound hydrolyses to ordinary tartaric acid during digestion. Its use is a targeted quality preservation tool with no health implications.
Generated from verified JECFA, EFSA, and regulatory data. All numerical values are sourced from the WHO/FAO JECFA Combined Compendium and EFSA OpenFoodTox 3.0.
Safety Assessment
| Body | Acceptable Daily Intake (ADI) | Year |
|---|---|---|
| JECFA | 0–30 mg/kg body weight/day (as tartaric acid (group ADI)) · JECFA 1978(Expressed as as tartaric acid (group ADI).) | 1978 |
| EFSA | — | — |
ADI = the amount of a substance a person can consume every day over a lifetime without appreciable health risk. Expressed as mg per kg body weight per day. Source: WHO/FAO JECFA Combined Compendium; EFSA OpenFoodTox 3.0.
Scientific Notes
Condensation polymer of tartaric acid; used exclusively in winemaking to prevent calcium tartrate crystal formation ('wine diamonds') in bottled wine.