How do growers and winemakers know when grapes are ripe? You can pay a lab to measure parameters like total dissolved solids and organic acid content down to the third decimal place, but an experienced human tongue is still the best instrument for balancing the myriad sensations which add up to what the trade calls “physiological ripeness.”
For winemakers, sugar is the least interesting compound in a grape. Yeasts feed on sugar, pumping out ethyl alcohol as a waste product—about one unit of alcohol for every two units of sugar metabolized. But alcohol is just alcohol; everything that makes wine Wine is due to other ingredients of grape juice.
By far the most significant are called, simply, “acids.” Fruit is ripe not when sugar content reaches some arbitrary level but when sugar and acidity are in agreeable balance. Too little sugar and the fruit tastes sour, “green”; too little acid and the flavor is flat, cloying. And unfortunately, well before grapes have built up sufficient sugar to make them worth fermenting, their acid content begins to dwindle.
If X percent rise in sugar meant Y percent decline in acid, deciding when to harvest would be a snap. It doesn’t work that way. Sugar production depends mostly on how many hours of sun the grapes get; retaining acid depends on how warm it is at night. One of the biggest factors making Eastern Washington prime wine-grape country is that summer days are consistently tank-top hot, while nights can be sweater, even mackinaw, cool. In some parts of the world (look no farther than Oregon’s Willamette Valley), weeks of overcast skies or rain can prevent grapes from ripening at all. The thing that gives growers and vintners gray hairs here is deciding: Is the gain in sugar from one more day on the vine worth the risk of a wine rendered short-lived and bland from lack of acid?
Adding to the stress is the fact that once you make your call, you won’t know if you were right for months, sometimes years. That’s what makes winemaking so frustrating yet fascinating—and what separates great growers and vintners from their fellows.
GET THIS!
Grapes in Washington get so much sun that our wines suffer more often from too much sugar and/or alcohol than too little: “Bone dry” is not a word that comes up often here. Hinzerling’s Mike Wallace has found a way around that: His 2000 Bickelton Vineyard chardonnay is grown at one of the highest (and hence coolest) sites in the state, on the Horseheaven Hills southwest of Prosser. Lemony, juicy, utterly dry, it’s a perfect chard for people who hate chards. And just $8 a bottle.
