Pinking

Pinking is the term used to describe the appearance of a salmon-red color that may appear in some bottled white wines, produced only from white grape varieties under reducing winemaking conditions. Generally, it is perceived as an undesirable phenomenon for the wine industry and consumers. Although with seasonal and regional variations, pinking has been observed worldwide in wines produced from different white grape varieties. Several hypotheses have been raised for the explanation of the pinking phenomena in white wines, the most recent one being that in the case of Síria white grape varieties; it was clearly shown that its appearance is due to the presence of small quantities of anthocyanins, mainly malvidin-3-O-glucoside in the pulp and skin. The presence of small amounts of anthocyanins in the skin of other white grape varieties susceptible to pinking has also been shown. There are some preventive or curative enological treatments for handling the pinking problem, including the addition of polyvinylpolypyrrolidone in the grape juice or young wine for removing the pinking precursors before or after the appearance of the pink color in white wines. Another treatment is increasing the redox potential using ascorbic acid in the prebottling stage for avoiding its appearance.