Spotlight on Wine Grape Harvesting

Why is it that opening a new bottle of wine often carries with it the anticipation and excitement of expecting the unexpected? As with any kind of farming, winemaking is in large part a science, in this case viticulture, to be precise. Yet the effort that goes into producing wines has as much to do with art as it does science, and can create grapes which are both ideal for great wine yet utterly unique.

Establishing the best time to pick grapes is a delicate process, in which ripeness is certainly a primary determining factor. Ripeness is dictated by sugar, acid, and tannin levels. However, weather and location also impact the crop and are important aspects to consider when recognizing the peak harvest time. Weather conditions such as extreme heat, hail and frost can damage grapes and cause vine diseases. To ensure the highest quality and taste, it is vital to harvest at the right moment, one that not only maximizes all the benefits nature bestows upon the grapes, but also shields the grapes from imminent threats posed by the seasons.

North America's winemakers must take into account a wide range of viticultural variables. In California, many sparkling wine grapes are harvested very early in the season to maintain acidity in the wine, while ice wines from Canada and many other areas of the United States are harvested in the winter. Although grape-picking times can vary, the vast majority of wine grape harvesting on this continent occurs between August and October.

During this time, winemakers must astutely judge the tannin, sugar and acidity levels in the grape. They use a refractometer to measure sugar levels, and calculate the acidity of the grape by administering a tiltration test. Surprisingly, there is no such machine or modern innovation that tests tannin ripeness. The only way to measure tannins is by tasting the grape. In order for practitioners to accurately identify the moment of ripeness, they must employ a great deal of wine tasting skill and experience.

Once the winemakers have determined that the grapes are ripe, the final stage of harvesting begins. For the actual picking of the grapes, winemakers have the option to harvest mechanically or to hand-pick. The question of which method is best, is a source of debate between different winemakers. Mechanical harvesting works by beating the grape vines with rubber sticks. The grapes then fall onto a conveyor belt and are gathered into a holding bin. Mechanical harvesting is an affordable and efficient process. However, the machines can have difficulty determining grapes from mud, leaves, and other particles. While more expensive and time-consuming, hand-picking is a method that consistently results in high quality wines. Hand-pickers are knowledgeable workers who are able to discern and gently pick only the healthiest grapes.

Ultimately, viticulture is dependent upon human taste and aesthetic judgement, and the resulting processes can blend scientific knowledge and artistic talent with all the complexity of an unforgettable glass of wine...

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