The work of a whole year is collected in a few weeks. From August through October in the northern hemisphere –from February to April in the Southern one-, vineyards come alive with the excitement of harvest. After vines enter the stage of veraison –when grapes start to become into mature hues-, growers start to monitor the development of the grapes. When berries ripen, the acidity levels decrease while the sugars increase. The more sugars in the grapes, the higher the alcohol level of the wine, since these elements will be fermented into alcohol. Flavors develop and the tannins soften. Winemakers check the phenolic maturity and physiological ripeness to get a good balance between all the mentioned compounds and get ready for the harvest.
Generally, the harvest starts at early/mid-August with grapes for sparkling wines, since high acidity is desirable. Next, grapes for the white wines make their way during late August/early September, when varieties such as Pinot Gris, Sauvignon Blanc or Chardonnay are harvested. Harvest continues through late October for red varieties like Merlot or Syrah, while late-harvest wines, such as the elaborated with Cabernet Sauvignon, last the longest allowing grapes to produce more highly concentrated sugars.
Of course, the timing of the harvest is one of the most decisions for winemakers and usually varies from a year to the next. There can even be a slight difference of a few weeks between regions and growers follow weather forecasts very carefully. Excessive rain, hails, heat waves or frosts can ruin a whole year’s hard work. Depending on the grape maturity state and the weather reports, winegrowers may move the harvest forward or delay it.
Grapes must be picked early in the cool of the morning or even during the night because as soon as they are picked, they start to deteriorate. The best is to process them when they are cool and protected by their native yeast, so it is necessary to avoid the heat. There are two methods of harvesting: by hand and mechanical. The mechanical harvest is more economical and faster, and it requires fewer efforts from the harvester. A machine shakes the bunches and grapes fall into hoppers that likewise are emptied into trailers. A negative aspect of this method is that it does not discriminate between healthy mature and spoilt immature bunches.
The manual harvest is more expensive but it allows to select the appropriate bunches, so this is the chosen method for high-quality wines. Each bunch is cut individually with a knife or scissors and put into baskets, while the spoilt bunches are disposed. It is a very careful process where harvesters must pay extreme attention so that the grapes’ quality is not affected.
Once the grapes have been harvested, the work continues in the cellar, where the wine begins to take shape. This next step is also critical, so be sure everything is going alright. How? Performing a WineSeq test on your musts of fermented liquids.