Abstract Glenn Jeffries

Comparison of Tannin Addition Protocols and Their Effects on Extraction of Grape Phenolics during Red Wine Fermentation

Glenn Jeffries
*Oak Solutions Group, 2557 Napa Valley Corporate Dr., Suite D,
Napa, CA 94558 (gjeffries@oaksolutionsgroup.com)

Extraction and retention of red wine phenolics, particularly anthocyanins and tannins, have historically been a primary concern for many red wine producers. Two competing protocols to facilitate the extraction and retention of phenolics by adding exogenous oenological tannin were compared for their relative efficacy. The first protocol involves adding exogenous tannin in a single full-dose at or immediately after destemming/crushing of the grapes. The second protocol, commonly referred to as the ‘sacrificial’ protocol, involves splitting the addition into two half-doses. The first half-dose, or sacrificial dose, is applied at or immediately after destemming/crushing, and the second half-dose is added a few days later. The specific mechanisms involved in the extraction dynamics are not elucidated here; however, phenolic profiling before and during fermentation and one full year after, using UV-Vis and AWRI tannin portal methodology, has shown a clear advantage to the single-dose protocol in extraction and retention of grape phenolics. Possible explanations are proposed and discussed.

Funding Support: Oak Solutions Group