Harvesting of most grape varieties occurs once a year in both the Northern and Southern hemispheres. There is no definitive answer to exactly when wine grapes should be harvested — it depends largely on the grape variety being grown and what end product the winemaker is looking to achieve. You also need to consider other mitigating factors. Such as weather, consistency of climate during the growing season, and condition of the terroir. In any case, a winemaker’s decision on time of harvest (yes, hours make a difference!) will be critical in determining what a wine will taste like.
Indications for Time of Harvest
Some winemakers know the status of their grapes by looking at them, while others like to double check ripeness using scientific techniques. In either case, the specific time of wine grape harvest is determined by how ripe a a grape is. Ripeness is measured, for the most part, by three crucial factors: tannin, sugar and acid concentrations. These levels can vary widely, and can be tested for by using scientific measurement techniques should the winemaker choose. The less ripe a wine grape is, the more acid it will typically retain. Ultimately, harvest depends on what type of wine the Vintner is looking to create.
What are the most common wine grape harvest months?
In popular wine growing regions throughout the Northern hemisphere, harvest season for grapes occurs throughout July, August, September and sometimes as late as October. Harvests throughout the Southern hemisphere will typically occur in February, March and April. No matter what hemisphere, warmer areas residing closer to the equator will very often harvest their grapes a bit earlier as they will ripen sooner.
Science is Helping to Craft Better Wine
Thanks to technology, Vintners no longer need to eat grapes to determine if they’re ready for harvest. They can now get much more specific in determining optimal ripeness for a particular wine product. Using scientific instruments such as a refractometer, they can see sugar content levels with amazing accuracy. Using the chemical compound phenolphthalein, they can see how much acid resides within a grape. Unfortunately, there’s no perfect scientific test to determine tannin levels. Vintners with a desire to achieve various tannin levels in their grapes very often will still determine this using only their sense of taste. I like that — it keeps wine more personal.
Getting Specific with Weather as a Determining Factor
Biodynamic vintners, such as those within the Burgundy region of France, will harvest their grapes dependent upon the actions of the various micro-climates throughout their vineyards. For example, if rain, frost or hail is anticipated on a particular day in September, the winemaker may choose to pick their grapes prior to one of those events. On the other hand, if rainfall was minimal during the growing season and heat was consistently high, the winemaker may opt to harvest their grape vines following an anticipated rainfall.
Becoming One With the Vineyard
I love listening to winemakers who wander between their grape vines and look at them as if their speaking. Some biodynamic winemakers know their vines so well they claim that the plants will tell them when they’re ready for harvest. Whether you consider it absurd or not, this notion speaks to a much deeper truth. The grape vines, the earth, and us — human beings, are all part of the same “stuff.” We began from the same single point at the beginning of the universe. As Carl Sagan put it, we’re all “star stuff.” So who’s to say we can’t relate on a deeper level to the wines we create? Let’s face it, the biodynamic wine industry is taking off. What’s funny to me is, many of these winemakers have been doing it for hundreds of years. It’s just now that mainstream media has brought the quality of craftsmanship to the center stage.