Gluconic Acid in California Wines

Abstract

Seventy red and white California table wines, produced primarily by Northern California wineries, were assayed for gluconic acid by an enzymatic procedure. The levels of gluconate ranged from none to 3.09 g/L, averaging 0.21 g/L for reds and 0.24 g/L for the whites. Eight white Bordeaux wines, labeled `Sauternes,' also assayed for gluconic acid, contained 1.28-5.89 g/L. Preliminary evidence suggests that gluconate was present in the assayed wines as a result of mold metabolism prior to vinification.