Survey of Biotin, Pantothenic Acid, and Assimilable Nitrogen in Winegrapes from the Pacific Northwest

Winegrape samples were collected from 2001 to 2003 in vineyards located in the Pacific Northwest. Riesling and Chardonnay had lower concentrations of biotin (often <1 μg/L) than did red cultivars. The concentration of pantothenic acid (mean 513 ± 181 mg/L) was lowest in Riesling but highest in Chardonnay. Most samples contained low amounts of yeast assimilable nitrogen (YAN), ranging from 25 to 336 mg/L (mean 124 ± 62 mg/L). While most grape samples had adequate amounts of pantothenic acid for fermentation, many were deficient in biotin or YAN.