Calcium tartrate, exactly calcium L-tartrate, is a byproduct of the wine industry, prepared from wine fermentation dregs.

[4] Its solubility decreases with lower temperature, which results in the forming of whitish (in red wine often reddish) crystalline clusters as it precipitates.

As E number E354, it finds use as a food preservative and acidity regulator.

Like tartaric acid, calcium tartrate has two asymmetric carbons, hence it has two chiral isomers and a non-chiral isomer (meso-form).

Most calcium tartrate of biological origin is the chiral levorotatory (–) isomer.