Barrel-to-Barrel Variation of Volatile Oak Extractives in Barrel-Fermented Chardonnay

¹ Department of Viticulture & Enology, University of California, Davis, CA 95616-8749.

Barrel-to-barrel variation in barrel-fermented wines was measured by determining the concentrations of seven volatile oak extractives — furfural, 5-methylfurfural, furfuryl alcohol, guaiacol, cis-ß-methyl--octalactone, trans-ß-methyl--octalactone, and syringol — in individual barrels of four 10-barrel lots, two French and two American oak — of barrel-fermented Chardonnay after seven months of oak aging. Within individual commercial production lots, the variance of individual compounds averaged 27% and ranged from 15% to 40% as measured by the percentage of standard deviation with respect to the mean. Statistical analysis of the data showed that an experiment with four barrels per lot would yield chemical levels within 30% of the barrel population (a specific barrel type from a specific producer) while a 10-barrel lot would be within 20% and a 39-barrel lot would be within 10%. However, the use of one barrel could yield chemical levels more than 50% different from the population.

Key words: oak, barrel fermentation, Chardonnay, ellagitannins

Submitted on March 17, 1995