Relative Efficacy of High-Pressure Hot Water and High-Power Ultrasonics for Wine Oak Barrel Sanitization

A significant amount of capital and maintenance is invested in oak barrels, which contribute greatly to wine quality. If not cleaned correctly, barrels can accumulate tartrate deposits and wine spoilage organisms, which can be detrimental to wine quality. We examined the efficacy of using high-power ultrasonics (HPU) for sanitization of wine barrels using the spoilage yeast Dekkera (Brettanomyces) bruxellensis as the test organism and indirectly compared it to standard hot water washing practices. Both 1- and 3-year-old oak were investigated and no culturable cells were detected on the surface (0 to 2 mm) or subsurface (2 to 4 mm) of the oak after treatment with HPU in hot water (60 degrees C). Additionally, wines stored over a 12-month period in barrels initially cleaned with hot water, cold water, or HPU did not differ in their extraction of oak compounds, nor could these wines be differentiated by a sensory panel. Thus, HPU did not adversely affect oak extraction into wine.