Why are red wine grapes fermented with the grape skins but white wine grapes aren’t?
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Dear Dr. Vinny,
Why are red wine grapes fermented with the grape skins but white wine grapes aren’t?
—Marshall, Kingston, Pa.
Dear Marshall,
Grape skins are a source of tannins, phenols and color pigments in wine. You’re correct that the production of a typical white wine involves separating the white wine grape juice from the solids of the crushed grapes (and fermenting just the juice), while red wines go through maceration, when the crushed grape solids (skins, stems, seeds, etc.,) are allowed to steep in the juice for a period of time, imparting color, flavor and texture to red (and rosé!) wines.
The reason that winemakers don’t use the skins to make most white wines is that doing so would add characteristics that they (and consumers) don’t usually want in a white wine, like tannins and darker color, and the wine would no longer have that crisp and refreshing character that so many white wines provide.
Some skin-contact wines are made from white grapes, though. They’re often referred to as “orange wines,” because the added color of the skins tends to lend the wines a coppery appearance, or something that reminds me of apple cider.
It’s not just the color, but the texture and flavors of skin-contact whites that can be unusual if you’re not familiar with them. They have nutty or caramel notes, and the fresh fruit flavors are quieter. There’s more body to the wines—they have more tannins—but that can also make the wines seem a bit coarser, and even a bit dry on the finish. Tasting them often reminds me of the bitter, parching sensation of almond skins.
Skin-contact white wines are getting a lot more attention than they used to, but they’ve been made for ages in France’s Jura region and Italy's Friuli/Venezia-Giulia region, as well as in Slovenia and the former Soviet republic of Georgia. Most of these wines are made in small quantities, and I’d be surprised if the category ever goes “mainstream”—and I think that’s part of the appeal to fans of these wines.
—Dr. Vinny