Glutathione, the secret to fruity wines (or one of them, anyway)

Originally published in Palate Press: The online wine magazine

One of the things a lot of people look for in wines – in particular young-drinking wines – is a good dose of clean, expressive fruit. Logically, a great number of winemakers seek to provide just that, in a precise and reliable manner.

As they do so, one of the things these winemakers have to fight is oxidation, which tends to move aromas from fresh fruit to cooked, bruised or dried fruit, or even take the fruit flavors out altogether. But beyond one obvious thing – don’t let your wine get too much air – what elements, present in the wine itself allow oxidation to be kept at bay and freshness to be preserved?

Certain things like acidity or tannins can help, but so can another component whose role in both fermentation and aging is truly surprising: glutathione.

This chemical component, which occurs naturally in many plants, including grapes, is remarkably powerful at fighting the effects of oxygen, in particular during the fermentation process. As research progresses, its role and its workings are gradually becoming clear. “It’s only recently that we’ve started to come to grips with it”, says Dr Maurizio Ugliano, enological research manager for Nomacorc, a synthetic cork company that has collaborated with a number of institutions around the world on projects regarding oxygen management in winemaking.

The role played by glutathione has mostly been studied in white wines, notably in sauvignon blanc, Ugliano explains. You know those passion fruit aromas in New Zealand sauvignon blanc? They are provided by a series of aromatic components becoming to a family called thiols. Thiols, however, are extremely sensitive to oxygen, and can degrade fast if nothing stands in the way …