This time of year brings back many childhood memories for me. My father and I would go to the train tracks near City Centre to greet the arrival of wine grapes from California. The cases would come out of the huge train cars which to a small child resembled a gymnasium. The grapes today arrive by truck and are sold directly by merchants across the city. But before our dads and other amateur winemakers can get their hands on them, the grapes need to be harvested in California.
What determines when a grape is harvested? There are a number of factors in this important step in making wine. Obviously the grape has to be ripe. Picked too early, and the result will be a green, vegetal wine with not enough sugar. Pick it too late and the resulting wine can be high in alcohol and the fruit and tannins will overpower the acidity in the wine. A ripe grape has the right combination of sugar, acidity and tannins. Many experienced winemakers can tell by simply tasting the grape in the vineyard. But like everything else today, science also plays a role. The sweetness level in wine is measured in Brix. The sweetness level is determined by how much sucrose is present in the grape. This level will also determine how much alcohol the wine will obtain. So for example Cabernet Sauvignon from Napa will be picked at 26-27 Brix. This will result in a wine with about 14.5% alcohol by volume, (ABV). In a climate like Bordeaux in France, the grape is ripe at 24 Brix and will produce a wine at 13.5% (ABV). Brix levels are measured using a Hydrometer (Winefolly.com). When the winemaker determines that the perfect Brix have been reached, the harvest takes place. All this can be jeopardized if the weather does not cooperate. Heat waves and hail obviously are not welcomed at harvest. Rain will throw Brix levels off given that the grape has now taken on extra water. Science also looks at physiological ripeness. Are the seeds, skin and stems also ripe? For example, are the seeds still bitter? If they are still bitter, their colour is green, if they are ripe the colour is almost yellow.
Grape varieties do not ripen at the same time. For example, in the Northern Hemisphere, Pinot Gris, Sauvignon Blanc, Chardonnay and Pinot Noir ripen earlier typically in late August/early September. Then you have Chenin Blanc, Viognier, and Merlot in late September/early October. This is followed by Shiraz and Cabernet Sauvignon in October/November. So for example, in an area with a short growing season like Ontario, grapes such as Riesling and pinot noir do well, since they are the first to ripen. Cabernet Sauvignon, is problematic in Ontario, since this grape needs a long growing season, something which is not always guaranteed in this area. In the Southern Hemisphere the harvest would be between February to April. Whether it be the Northern or Southern Hemisphere, these months are approximations for still wines and every year this can change according to the weather. As well, you must take into account the winemaker’s style. For example, late harvest wines are harvested in late fall and ice wine in January in the Northern Hemisphere (Niagara) or June for late harvest wines in the Southern Hemisphere (New Zealand).
Now that the winemaker has determined that the grapes can be harvested, the grapes need to be picked. This can be done by hand or by using a mechanical harvester. Both have their pros and cons which each side in this issue will be proud to point out. When I spoke with my cousin in Abruzzo, all of the grapes in his vineyard are picked by hand. The picking crew is made up of mostly seniors from the area and Polish labour. My cousin swears by hand picking, indicating that human hands are better equipped to pick the delicate grapes. Picking by hand does not break the skins thereby protecting the juice from oxidation. Plus you can eliminate by hand those grapes that are not ripe or bunches that have rotted. My cousin made excellent points. Plus if you have ever been to Abruzzo or many areas of Italy, many of the vines grow on hills which make mechanical harvesting difficult.
While these machines have been around for decades, mechanical harvesting is new to the vineyard. The choice of whether to harvest by hand or machine is determined by tradition but also economics. In areas where labour is plentiful and low cost, hand picking is the norm. So for example, migrant workers from North African and Sub Saharan Africa are found in the vineyards of Italy. Whereas in California, they are from Mexico. Even here at home, when I last visited Chateau du Charm in Niagara, the worker pruning the vineyard was Mexican. In places where labour is hard to find, such as Australia, mechanical harvesting is dominant. A mechanical vine harvester works by beating the vine with rubber sticks to get the vine to drop its fruit onto a conveyor belt that brings the fruit to a holding bin. As technology improves mechanical harvesters have become more sophisticated in distinguishing grape clusters from mud, leaves and other particles. (T. Stevenson “The Sotheby’s Wine Encyclopedia” page 22).
Mechanical harvesters can run 24 hours a day, shortening the process, which is important if the forecast is for rain. As well, picking at night when the grapes are cooler is a distinct advantage as the fruit is better preserved until it reaches the winery. In a large vineyard which lies on rather flat land, the mechanical harvester is very efficient. In terms of cost, the mechanical harvesters cost in the range of $400 000! Very expensive you may say. However, keep in mind that in a 10 hour shift, eight operators will harvest 200 tons. While a crew of 30 workers picking the grapes by hand will harvest 20 tons in a 10 hour shift. That said, in many wineries, both hand and mechanical harvesting is used. The delicate Pinot Noir grape is always picked by hand. As labour costs increase and vineyards continue to get bigger, mechanical harvesting will, in the not too distant future, be the norm. However, I am convinced we will always drink wine made with grapes that were handpicked. This is one tradition which I honestly believe will not disappear.
Grazie e salute!
By: Domenico Cellucci