Shelburne, Vt.—Shelburne Vineyard is one of just two wineries in Vermont to grow vinifera grapes. Instead, winemaker Ethan Joseph focuses largely on Marquette, a hybrid grape less than a decade old. Developed by Peter Hemstad at the University of Minnesota and released in 2006, Marquette is a complex hybrid of V. riparia, V. vinifera and French hybrid cultivar Ravat 262. One of its grandparents was Pinot Noir.

In many ways, Joseph treats Marquette like a vinifera grape, and the resulting wines have garnered critical praise including four Best of Show awards at the International Cold Climate Wine Competition.

Joseph spoke Feb. 6 at the Cold Climate Grape Conference in Minneapolis, Minn., where he shared his winery’s approach to growing and vinifying Marquette.

Joseph says Marquette “is a premium variety, and we need to treat it as such. From a wine-quality perspective, it’s very important to our industry.”

Training Marquette
Planted entirely in north-south rows and almost exclusively trained on high-wire cordons (8 by 10 feet and 6 by 9 feet) that are replaced often, the mature vines get balanced pruning and then leaf pulling shortly after bloom.

“We call it ‘vine swimming’ because we’re doing this,” Joseph said, churning his arms like a freestyle swimmer. “This is an arduous task, but the benefits are enormous. You’re going to get much better clusters, and they’ll have their own microclimate.”

Joseph said he gets soil tests every five years and petiole tests every other year. He and his crew do spraying based on disease history. Marquette is most prone to black rot and phomopsis, he said, “And it’s really important to rotate (fungicide) materials.” As for weed control, “We want the native plants to dominate, to keep vine vigorousness down.”

Canopy management is “more like a typical vinifera than a hybrid. We don’t have an option.” While many growers emphasize high yields on hybrid grapevines, according to Joseph, Shelburne’s Marquette grapes are “managed to optimize cluster exposure, heat accumulation and ripening. That requires a big labor expense, but it is justified in the end product.”

Marquette is proving quite vigorous, Joseph said, with the winery getting 4 to 5 tons per acre, almost double the output of four years ago, and “with a big improvement in grape quality.” It is usually picked in late September, after about 2,300 growing degree-days.

“We taste the berries and the juice and the seeds and the stems,” Joseph said, harvesting “at no higher than 26.5° Brix, usually before optimum seed and stem ripeness. I’ve never gotten complete stem ripeness with Marquette.” The pH is usually 3.1 to 3.2, he said.

Winemaking style
Once the grapes are at the winery, most of them are de-stemmed. In recent years Joseph said he has gone about 10% whole-cluster, waiting 24 hours before inoculation with D254 yeast.

“Research shows that Marquette has good tannins in its skins,” Joseph said. “Even if the skins are not quite ripe, you’re going to get more and better tannins.”

Joseph said he prefers a longer, slower fermentation for the Marquette, keeping the temperature in the mid-70°s F. Besides punch downs, Shelburne’s staff does what he calls “sump-overs,” which he describes as “a modified pump-over so that the solids in the must do not go through the pump. The bottom valve of the tank is opened, allowing must to flow out of the tank through a screen into a stainless ‘tub.’ Must free of solids is then pumped back over the top of the fermentation.” With that, and extended maceration of about 35 days, “you get softer tannins and more seed tannin extraction.”

The oak program has evolved. “We started with American, but we got too much vanilla,” Joseph said. “We tried a hybrid of French heads and American staves and still got vanilla. Our newest barrels are Hungarian. We tend to do about 20% new oak, and we’re starting to go lower.”

The winery uses sur lie aging with bâtonnage and ages its Marquette for nine to 16 months, topping the barrels once per month and regularly checking sulfur dioxide levels. There’s no fining or cold stabilizing.

“We test all the reserve barrels for richness, depth and complexity,” Joseph said. The 2012 Marquette Reserve was aged for 15 months. The result is a finished wine with aromas of cherry and red licorice and rich flavors of berries and toasted vanilla beans with a spicy, multi-layered finish.