Sparkling wine the production of still wine with some noted divergence. At the vineyard, grapes are harvested early when there is still high acid levels. In areas like Australia, winemakers aim to harvest the grapes at 17 to 20° brix. Unlike still wine production, high sugar levels are not ideal and grapes destined for sparkling wine production may be harvested at higher yields. Care is taken to avoid tannins and other phenolic compounds with many premium producers still choosing to harvest by hand rather than risk mechanical harvesting which may split the berries and encourage maceration between the skins and juice. The
Phenolic content in wine . Low molecular weight polyphenols, as well as elagitannins, are susceptible to be extracted from cork stoppers into the wine. The identified polyphenols are gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferyl, and sinapic aldehydes; the coumarins aesculetin and scopoletin; the ellagitannins are roburins A and E, grandinin, vescalagin and castalagin. Guaiacol is one of the molecules responsible for the cork taint wine fault. Flash release is a technique used in wine pressing. The technique allows for a better extraction of phenolic compounds. The exposure of wine to oxygen in limited quantities affects phenolic content. Depending on