When to Pick

Paul Blow

It’s wine harvest time, when leaves turn golden, days grow shorter, and winemakers face the biggest question of the year: when to pick the grapes. “It’s the time of year to tear your hair out,” says Robert Brittan, former winemaker at Napa’s Stags’ Leap Winery and now head of his own project, Brittan Family Vineyards, in Oregon.

The timing of harvest has a huge impact on wine quality, alcohol level, and style. Grapes picked underripe will yield tart, vegetal wines that can smell like asparagus. Overripe red grapes make wines that are gloopy, lack definition and structure, are high in alcohol, and are often insipid—like a sugary, unctuous Zinfandel. Perfect ripeness makes for clean, fresh-tasting, balanced wines you want to keep drinking. The problems are that it’s not easy to get grapes perfectly ripe, and not everyone agrees what that is. Over the last 10 to 20 years, some winemakers have been leaving grapes on the vine after the fruit has ripened, a practice called hang time. Those who do it say that they are “waiting for flavors to develop,” but Brittan thinks “people are simply doing it for overripe flavor.” Why go for overripe? Because it results in high-alcohol, jammy wines—the style that’s currently popular—as the grapes shrivel in the heat, losing water to evaporation, which in turn concentrates the sugars.

A refractometer tests sugar content.

Brittan prefers to tear his hair out than let his grapes ripen longer. In the 1970s, he says, winemakers relied on a device called the refractometer that gave a rudimentary assessment of the sugar content of grapes—measured in degrees Brix—to tell them when to pick. That method was rejected in the 1980s as formulaic picking “by the numbers”; winemakers learned that sugar levels are not always a good indication of ripeness. Since then, however, it’s become fashionable for vintners to brag that they can just tell by tasting the grapes.

Jim Clendenen of Au Bon Climat—a Pinot Noir and Chardonnay specialist in Santa Barbara County—isn’t shy about using instruments, and he tastes too, “but that only tells you so much. We pick when we have the right levels of sugars, acids, and pH to make a balanced wine. You can’t taste the flavors of a finished wine in the grapes. All you can taste is sugar and to some extent tannin and acidity.” Clendenen’s wines are typically at moderate to low (for California) levels of alcohol and are not known for the over-the-top sweetness of other wines. George Vierra, a Napa-based oenology teacher, concurs, saying, “Ninety percent of the flavor compounds in the wine are bound up in the grape skin and released by fermentation. It’s a fairly wasteful process to taste the fruit. Refractometers shouldn’t go away.”

Likewise, Wells Guthrie, owner of Copain Wines in Santa Rosa, California, told me that last year he instructed his grape growers to pick all his Pinot no riper than 23 degrees Brix. He was picking by the numbers, and his 2006 crop made delicious, low-alcohol wines. “You just have to believe that the flavors will be there,” he says. “You have to know your vineyards and trust them.”

Doug Fletcher, winemaker at Napa’s Chimney Rock, believes primarily in tasting the grapes but uses analysis to back it up. He is not looking for hang time but wants to extend his growing season as long as possible, despite Napa’s traditionally high September temperatures. “My technique is to squeeze all the pulp out of the grape, and then I just chew on the skins; I look for greenness and acidity.” Squeezing the pulp out allows him to taste the skin, in the absence of sugar. “It’s very confusing to taste the whole berry, because the sugar masks the tannin quite a lot.”

Fletcher is often able to coax his grapes to stay on the vine late into the season—not to get high sugar, but to encourage slow, even ripening. He explains why there’s confusion about picking times and ripeness in California. “We got our winegrowing notions from Europe, but … a lot of the European experience doesn’t work here,” he says. “Europe, for the most part, is sun-limited; they don’t get enough sugar. All their vineyard practices (grape thinning, trellising) are about getting maximum sugar accumulation in the grapes before the autumn rains. In California, when you thin the fruit, you get sugar faster, which is not what we want.” Fletcher advocates a policy that would in Europe sound like heresy: carry more fruit and more leaves to slow down the vines’ ability to mature them. “Our grapes are not getting overripe.”

But Fletcher also has another solution: a California winemaking textbook from the 1880s called The Wine Press and the Cellar. According to its author’s research, a good indication of when to pick is once the birds start eating the grapes. “That’s the first sign nature gives you that ripeness has been achieved,” says Fletcher. “And there just might be something to that.”

Jordan Mackay is a San Francisco–based wine and spirits specialist whose work has appeared in publications such as Gourmet, the Los Angeles Times, Food & Wine, and Decanter. Follow him on Twitter. Follow CHOW too, and become a fan on Facebook.