Stag’s Leap Wine Cellars

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Stag’s Leap Wine Cellars

Winemaking Articles

The highest quality berries find their way to the crusher.

A Legacy of Winemaking Excellence Continues: The New Mistral Sorting Table

It’s been an exciting past year as we’ve worked alongside our new stewards from Ste. Michelle Wine Estates and the Antinori family. We have affirmed our history and celebrated past achievements, but we’ve also started to re-define our future, setting our sights on attaining higher goals and pledging a continued commitment to quality and innovation.

Becoming part of a family of wineries has made many things possible for us. For one thing, our winemaking and viticulture teams have the benefit of a network of wineries and colleagues that are unrivaled in our industry. This network spans multiple continents and in the case of Antinori, goes back many generations. Access to that kind of expertise and experience and tapping into this vast pool of knowledge is something we are just starting to take advantage of.

We’ve also taken a fresh look at our Napa Valley winery, replacing and adding equipment and upgrading buildings. One piece of equipment our winemaking team is particularly excited about – and certainly one of our biggest investments in quality – is the Mistral Berry Sorting System, a new system for sorting just-harvested grapes as they enter into the winery.

Although handpicking our fruit into small bins allows us to selectively harvest fruit from the vineyard, what is fondly referred to as MOG (material other than grapes) such as leaves, rocks, petioles and tendrils can get into the picking pan and subsequently the bin that is delivered to the winery. There is also other plant material, dried, undeveloped, or broken berries within a cluster, for instance, that a picker cannot eliminate. That’s where the Mistral comes in. Currently in use at only a few dozen wineries around the country, the Mistral is considered to be the most sophisticated system for ensuring that only the cleanest, purest berries end up in the winery’s crusher.

“A piece of equipment like that was something we could only dream about,” says Winemaker Nicki Pruss. “But the Ste. Michelle-Antinori team made it a reality.”

When you see the Mistral in action, you understand why a winemaker would dream about having one. The system includes a series of vibrating sorting tables. The first table levels out the fruit clusters, allowing the crew to inspect and manually sort each cluster. At this stage, the team hand sorts, removing MOG as well as any clusters or parts of clusters that do not meet Stag’s Leap Wine Cellar’s standards. The vibrating action shakes loose imperfect berries and other debris, which falls through slots onto a screen where it is collected and discarded.

Subsequently, a conveyor lifts the fruit (whole clusters and berries) and feeds it to the destemmer at a slow, even pace. The fruit continues from there onto another vibrating table that further separates the juice and berries from any raisins or undesirable material. Then it is on to a leveling and accelerating table which arranges the berries into a single layer before it encounters the blower, in which a stream of air separates the intact berries from lighter waste material. Only the most perfect berries get transported to the crusher and tank.

The quality of the fruit that falls onto the last conveyor belt is impeccable. “We could not get this level of perfection by hand sorting a load of fruit in an eight hour shift,” says Nicki. “When you catch the fruit in your hand before it finishes its voyage to the tank, it looks like a handful of blueberries.”

Although the 2008 wines are far from finished, the Mistral sorting system is an amazing tool that has already raised the quality of the wines we are producing. “Tasting the wines from the tanks we’ve pressed off so far has been very exciting,” says Nicki. “Excellent depth of fruit, no green flavors and very nicely balanced tannins. I can’t wait to see how these wines evolve.”

The Mistral sorting table is just one example of good things to come with our new partners. Their commitment, expertise, and resources are unparalleled.

“The goal is to preserve and enhance the legacy of Stag’s Leap Wine Cellars and its vineyards,” says Nicki. “Investing in innovations like the Mistral will go a long way in helping us achieve that. We think you’ll enjoy the results.”