Two centuries in the ground
Californians have been cultivating grapes for more than two hundred years. What began with mission plantings became, over generations, the most productive fresh-grape region in the country — and the San Joaquin Valley sits at the centre of it.
The reason is not luck. It is the combination this Valley happens to hold: long hot days that build sugar, cool nights that hold acidity, deep alluvial soil, and irrigation districts built by the farming families who needed them. Very few places on earth line all of that up at once.
The Coachella and San Joaquin valleys grow 99 percent of all domestically produced table grapes in the country.
California Table Grape Commission
A season that runs half the year
California's table grape harvest opens in the Coachella Valley in spring and moves north. From roughly July, the San Joaquin Valley carries the crop — and keeps carrying it into December. That long northern run is why American grocery stores can stock domestic fresh grapes from May through January.
More than eighty varieties come out of those fields, in green, red and black. Some you will recognise by name at the festival; many were bred specifically for this Valley's heat.
At the festival
Table grapes are the easiest place to start tasting. Bring an appetite: sampling is the point, and the growers and commissions on site would rather hand you fruit than a brochure. If you have only ever bought grapes in a bag, tasting several varieties side by side is a genuinely different experience.