By late summer, there's an unmistakable feeling in the vineyard. The excitement of bud break has long passed. The vibrant yellow mustard blooms are a distant memory. The vines are full, the clusters have reached their final size, and after weeks of watching the grapes change color during veraison, our estate Cabernet Sauvignon is entering the final stretch before harvest.
If you visit our vineyard in Calistoga this time of year, you might think there's little left to do but wait. In reality, this is one of the busiest—and most important—times of the season.
Veraison Has Finished. Now the Waiting Begins.
Veraison, when grapes soften and change from green to their deep purple color, marks the beginning of ripening. Now that every cluster has completed this transformation, the vines are focused entirely on developing flavor. The berries are no longer growing much in size. Instead, they're changing on the inside—becoming sweeter, more complex, and more expressive every day. This is when patience becomes one of the vineyard's greatest virtues.
More Than Just Sugar
People often assume harvest begins when the grapes become sweet enough. While sugar is certainly important, it's only one piece of the puzzle. Every week—and eventually every day—we're evaluating several key factors. For our Winemaker, Rob Hunter, flavor maturity is the key factor.
Sugar (Brix)
Sugar levels tell us how much natural sweetness has developed and help determine the potential alcohol of the finished wine. As harvest approaches, Brix steadily climbs, but reaching a target number doesn't automatically mean it's time to pick.
Acidity
Acidity gives wine its freshness, brightness, and energy. As grapes ripen, acidity naturally decreases. Harvesting at the right moment means finding the balance between vibrant acidity and fully developed fruit. For Cabernet Sauvignon, this balance is essential to creating wines that are both powerful and elegant.
Tannin Ripeness
The hardest to measure is tannin development. We spend plenty of time tasting berries in the vineyard. The skins become softer. The seeds gradually shift from green to brown. The tannins become less aggressive and more refined. This is where experience matters. Laboratory numbers can tell us a lot, but they can't fully capture texture, flavor, and overall ripeness.
Every Vineyard Walk Tells a Story
During this stage of the season, our vineyard team walks the rows nearly every day.
We're watching for:
Uniform ripening across the vineyard
Vine health
Weather forecasts
Fruit condition
Flavor development
Every walk offers new information. Some days the changes are subtle. Other days it's remarkable how quickly the fruit evolves. The vineyard has its own rhythm, and our job is to listen carefully.
Why Calistoga Is Worth Waiting For
One of the advantages of growing Cabernet Sauvignon here in Calistoga is our location at the very top of Napa Valley. Warm afternoons help the fruit achieve beautiful ripeness, while cool evenings bring a dramatic diurnal temperature swing that slows the pace of ripening overnight. Those cooler nighttime temperatures allow the grapes to retain freshness while extending the growing season, giving flavors and tannins more time to develop naturally. It's one of the reasons Cabernet Sauvignon from Calistoga is known for its depth, richness, and structure, while still maintaining balance. Sometimes, the best thing we can do is simply give the vineyard a little more time.
Harvest Can't Be Scheduled
One of the questions we hear most often is: "When will harvest begin?"
The honest answer is…We don't know. We may have an educated guess, but Mother Nature always has the final say. The decision isn't made by the calendar. It's made by the vineyard. When sugar, acidity, tannins, FLAVOR, and weather all come together—that's when harvest begins. Not a day sooner.
The Anticipation Is Part of the Magic
Soon enough, the quiet rows of Cabernet Sauvignon will come alive with the energy of harvest. Until then, we'll keep walking the vineyard, tasting the fruit, and waiting for the vines to tell us they're ready. Because great Cabernet Sauvignon isn't picked on a schedule. It's picked at exactly the right moment.