Allison the viticulturalist weighs in on harvest

Posted by Andrea Robinson, MS on Monday, August 22, 2016

Napa Valley harvest: it’s not merely picking grapes. In these videos you’ll see how, when and what’s next, all of which are crucial keys to quality.

Harvest in Napa Valley is an exciting time, so I thought you’d like to see it for yourself, starting with the harvest of Sauvignon Blanc from my very own vineyard in the heart of the St. Helena sub-region of the Napa Valley. Here’s a short summary of when and how it’s done, from the vineyard to the vat.

Harvest dream date? Mature and cool, baby.  That may sound like a nifty dating profile, but in fact it is the ideal harvest date profile. Mature means grapes that are fully ripe, but not over-ripe, so that a bright and balancing acidity is retained. Cool refers to the temperature of the grapes at harvest. In the 12 years my husband John and I have owned this vineyard, we have always harvested very early in the morning when the air, and thus the grapes, are cool, because the chilly temperature helps minimize oxidation of the grapes and juice during their trip to the winery. Fortunately in the Napa Valley we can count on cool nights and mornings throughout the growing season–but what about ripeness? Check out the first video above, my live post from the early-morning harvest, where vineyardist Allison Cellini explains how winemaker Chris Tynan of Cliff Lede, the purchasers of our fruit, chose the harvest date of August 22. Like most Napa vintners, Cliff Lede conducts tests of sugar density as harvest approaches, but the final decision is based on taste.  Chris will sample clusters selected from around the vineyard, assessing the flavors in the juice, and chewing the skins and seeds to ensure they taste mature and mellow.

Want to help harvest? Bring your knife skills. If you’ve picked garden veggies or tree fruits you might be surprised that harvesting wine grapes isn’t really picking at all–it’s cutting. The woody stems of wine grape clusters are very firm–more like tree branches than plant stems, so a sharp, curved-blade harvester’s knife is critical to effective and speedy harvesting.

Fast hand, easy touch.  The Pointer Sisters were talking about the perfect love partner, not grape picker–where speed with a soft touch is crucial. As you’ll see in the above right video, harvesters speed through the vineyard both because they get paid by weight of grapes picked and want to make every second count, and because speeding the grapes out of the vineyard and into the winery while they are cool helps minimize oxidation, which is the enemy to wine quality from harvest, until the moment you pull the cork and pour a glass. At the same time, a gentle touch when handling each cluster is critical to ensure the grapes remain intact, since broken skins immediately allow oxidation of the juice.

Pressed for (a long) time. That’s the funny thing. After all this hurrying, the grapes arrive at the press for a long, languorously gentle squeeze in what is called a pneumatic, or bladder, press–a cylinder with a balloon-like bladder inside that inflates, pressing the grapes against the cylinder to gently massage out the juice and pulp, which flow by gravity–no harsh pumping–directly into the fermentation vat. One press-load, about 8 tons of grapes in our case, takes about half a day.

In my next post, we’ll check out how the fermentation is going, and see how grapes for red wine are handled – it’s quite a bit different!

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