Flash-Détente technology, designed to increase extraction of color from red grapes while minimizing seed tannins, was developed in France in the late 1990s.
But the machinery has only recently made its way to the United States. In fall 2009, during harvest, a Flash-Détente system was installed at Monterey Wine Co. in King City, Calif. The results of the custom-crush winery’s first experiments with the system were unveiled at a presentation and tasting Tuesday at the facility. The equipment is manufactured by Pera, based in Florensac, in France’s Languedoc-Roussillon region. David Bayle, an enologist with Pera, explained the technology to about three dozen California winemakers and winery officials. Flash-Détente, which translates roughly as “instant relaxation”, involves a combination of heating the grapes to about 185ºF, then sending them into a vacuum chamber where they are cooled. The cells of the grape skins are burst from the inside, allowing for better extraction of anthocyanins and skin tannins.
All this takes place before any alcoholic fermentation, so the more bitter tannins aren’t extracted. “We don’t get this green tannin that you sometimes get at the end of fermentation,” Bayle said. Another result of the process is the reduction of pyrazine compounds. Flash-Détente creates steam that goes into a condenser, and the condensate is loaded with pyrazines and other aromatic compounds, like the aromas associated with rot or mold. (The heating process also sterilizes the grapes.) Bayle acknowledged that some fruit aromas are also found in the condensate. “You smell the green first, and a tiny part of the flavor,” Bayle said of the condensate. Because vapor has been removed, the sugar level is increased in the remaining must. The winemaker can either work with the higher Brix level; add back the condensate; discard the condensate and add water; or a combination. When Flash-Détente concludes, the must has been cooled to 82ºF. Then the winemaker has two choices for fermentation. The grapes can be pressed and the juice — after clarification through either filtration or a centrifuge — is fermented, similar to a white wine. Or the must can be sent to a tank for traditional fermentation. The tasting compared not only samples made by traditional methods vs. Flash- Détente, but also samples that had been “flashed” and fermented on skins vs. “flashed” and fermented without skins. Color was the most obvious first difference. Both Zinfandel and Merlot were darker when they had undergone Flash-Détente. But many of the participants observed that the flashed samples had less varietal character. The Zinfandel, for example, lost its spicy, peppery quality. A pair of cool-climate Merlot samples showed the effect on pyrazines. The traditionally made sample had a lot of vegetal character, while the flashed sample was fruitier and fresher. Two Merlot samples — both flashed, but one fermented with skins and one fermented without — displayed some stark differences. The wine fermented without skins had a more tutti-frutti character and not much mid-palate. Eric Laumann, general manager and winemaker at Monterey Wine Co., said he worked with about half a dozen of the winery’s clients on the initial Flash-Détente experiments. “We really didn’t know what we were doing,” he said. “There are so many variables that you can do with this.” He likes the options that the process provides. “It gives you blending components for complexity,” he said.
French research indicates that Flash-Détente not only accelerates and increases the extraction of anthocyanins, but that wines subjected to the process also hold their color longer. In addition to France and King City, the system is being used in Chile, Argentina, Australia, South Africa and Russia. There is also a pilot unit in California, but George Cortessis of Process Engineers in Hayward, Calif., which distributes the system, wouldn’t disclose its location. Cortessis said Flash-Détente is most appropriate for use on low-quality grapes. But he added that it had other advantages, such as the ability to create a variety of styles from the same grapes. And for large-scale producers, he said, Flash-Détente is “a way to short-circuit the red winemaking process.” When the juice is fermented without the skins, there’s no pumping over or punching down, and no dirty work of mucking skins and seeds out of the fermentation tanks. Laumann thinks the equipment’s greatest asset is that it simply gives winemakers a valuable tool, whether the grapes are substandard or not. “It’s nice to have this tool to fall back on” when the fruit is problematic, he said, “but I don’t think that’s really its ultimate use.” The system in use at Monterey Wine Co. can process 20 tons per hour. Laumann said the cost of the unit and the installation — including plumbing, electrical, a boiler, cooling tower, centrifuge, etc. — was close to $2 million, although the price might be less for a winery with some of that infrastructure already in place.
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