White grapes are really purple grapes with two genes switched off
Every green 'white' grape descends from a purple ancestor. Mutations in two regulatory genes shut down the pigments that colour red wine, leaving pale fruit behind. That is just one quirk of a plant people have cultivated for roughly 8,000 years, and whose skins carry the wild yeast that likely gave us wine.
Botanically, a grape is a berry of the woody vine genus Vitis, growing in clusters of 15 to 300. Cultivation began in the Middle East some 6,000 to 8,000 years ago. Because yeast lives naturally on grape skins, fermentation was almost inevitable, and the earliest evidence of winemaking playing a central cultural role comes from Georgia about 8,000 years ago. Armenia's Areni-1 cave holds the oldest known winery, from around 4000 BC, and Cyprus claims both 3500 BC wine jars and Commandaria, a sweet dessert wine traced to 2000 BC. The Syrah grape may take its name from Shiraz, famous for fine wines by the ninth century AD.
Ripening is a two-stage chemistry lesson. Young berries build up tartaric and then malic acid, which gives them tartness. At a stage called veraison, beginning around August in the Northern Hemisphere and lasting about 45 days, they darken, swell and fill with sugar as sucrose from the leaves splits into glucose and fructose. Grapes stop ripening once picked, so timing is everything. Wine grapes are harvested at roughly 24 percent sugar by weight, whereas commercial juice from table grapes runs nearer 15 percent.
Nearly all grapes come from one species, Vitis vinifera, yet breeding has split them sharply. Table grapes are large, thin-skinned and mostly seedless, and since vines are propagated from cuttings, seedlessness poses no problem except for breeders. Wine grapes are small, seeded and thick-skinned, because much of a wine's aroma comes from the skin. In North America, Ephraim Bull of Concord, Massachusetts, bred the Concord grape from wild vines in the nineteenth century; it now supplies most of the continent's purple juice.
About 71 percent of the world's grapes become wine, 27 percent are eaten fresh and 2 percent are dried. China led the 72.5 million tonnes produced in 2023, while Spain had the most vineyard land. The words are tangled too: 'raisin' means a fresh grape in French, and 'currant' is a corruption of Corinth grape.
Source: Grape
