Fertaric acid is a hydroxycinnamic acid found in wine and grapes. It is an ester formed from ferulic acid bound to tartaric acid. It is a metabolite of caftaric acid after caftaric acid has been fed to rats. Fertaric acid is then found in plasma, kidney, and urine. References O-methylated hydroxycinnamic acids Hydroxycinnamic acid esters Vinylogous carboxylic acids