It used to be simple. If you grew wine grapes, you picked them when they began to taste sweet. You probably didn’t wait too long. Birds, deer, and other predators like to eat ripe fruit, and autumn rain can bring rot. Better to harvest the crop early than never.
In the nineteenth century, science and technology combined to make deciding when to harvest more precise. A German chemist, A. F. W. Brix, used a hydrometer in his laboratory to measure the sugar level of grape juice, giving his name to a scale now used for just that purpose. Other scientists soon came up with an even better instrument, a portable refractometer that measured the brix level of a liquid’s dissolved solids (ninety percent of which are sugar). Refractometers were heavy and cumbersome to use at first, but by the mid-twentieth century small, handheld versions had become quite commonplace. Growers trusted them to determine when to start picking their grapes.
Since then, the question of what constitutes ripeness has become more vexed. Vintners now know that sugar content is not the only indicator. A host of other factors, including seed color, pulp texture, the condition of the stems in a cluster, and the relative pliancy of the grape skins, turn out to be just as important. Taken together, these comprise what is sometimes called “physiological ripeness” (as opposed to chemical ripeness), and conscientious growers today pay just as much attention to them as they do to easily calibrated sugar levels. Since harsh-tasting wines can sometimes come from grapes with acceptable sugars but inadequate physiological indicators, many growers today leave their fruit hanging on the vine far longer than they would have a generation ago.
Super-ripe fruit, however, tastes first and foremost sweet. Eat a peach that’s been left sitting on your windowsill a bit too long, or a melon that was picked a day or two late. The generic taste of sugar proves dominant. By contrast, when you eat fruit that is ripe but not over-ripe, the principal flavor is much more particular. You taste the peach before the sugar, and if you’ve had experience with different types, you can taste white or yellow, freestone or clingstone. In short, less sugar enables the peach’s flavor to be more distinctive.
The same, surely, is true when fruit juice, specifically grape juice, is fermented. If, like me, you find that an awful lot of the wines you drink today taste similar, their regional as well as their varietal identities obscured by their sweetness, one of the main culprits has to be the current vogue of ripeness defined in physiological terms.
Particularly in warm climes (and the grape-growing world is getting warmer), physiological ripeness comes at a price–high, often excessive, levels of sugar. To make more distinctive-tasting wines, wouldn’t it make sense to ferment a few green seeds or tough skins, or a little firm flesh, if doing so meant keeping sugar levels more reasonable? The alternative to today’s often overly ripe wines isn’t green, hard, vegetal-tasting ones. Instead, it’s balance, which after all is what all good wines have long needed to demonstrate.
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