Differences in Phenolic Profile between Oak Wood and Stainless Steel Fermentation in White Wines

Abstract

Wine consumers demand white wines with different flavor profiles. Fermentation in oak barrels leads to wines with much more complex sensory properties, largely attributed to the phenols extracted from oak wood. Winemakers are aware of the importance of phenolic compounds, which give astringency and bitterness to wood-matured wines. We examined the differences in phenolic compounds in white wines that had been fermented in oak barrels as compared to stainless steel vats. To evaluate the effect of oak fermentation, Chardonnay and Picapoll free-run juices were fermented at an industrial scale in wooden barrels at the same winery, while controls were fermented in stainless steel. The presence of characteristic oak-wood phenols such as coniferaldehyde, sinapinaldehyde, syringaldehyde (aromatic aldehydes), and scopoletin (a coumarin) were found in the white wines Picapoll and Chardonnay fermented in barrels, but were not detected in the same wines fermented in stainless steel vats. The presence of volatile compounds such as 4-ethyl-guaiacol, 4-vinylphenol, eugenol, β-methyl-γ-octalactone, and furan compounds were also observed in Picapoll and Chardonnay wines fermented in oak wood.