January 2011 Issue of Wines & Vines

Flash Extraction Goes to Work

Winemakers excited about effects on phenolics, flavor isolation

by Laurie Daniel

The 6,000-gallon stainless steel tank doesn’t stand out much at the Monterey Wine Co., a custom crush facility in King City, Calif., that can process 9,000 tons per year. But the intermittent explosions—pop, pop, pop, every few seconds—get your attention.

This is Flash Détente in action. The French machine—and similar flash extraction equipment developed in Italy and being used in Woodbridge, Calif.—is used to increase the extraction of color and skin tannins, while also reducing pyrazine compounds and the aromas associated with rot and mold. The latter uses proved to be especially handy during the cool, damp 2010 vintage, when mold and rot were problems in many vineyards and, in some cases, late-maturing grapes didn’t have the chance to ripen properly.

Flash extraction has been around for more than 10 years and used in Europe, South America, Australia and elsewhere. But the first commercial unit in the United States wasn’t installed until just before the 2009 harvest, at Monterey Wine Co. That first year, Flash Détente was used on about 500 tons of grapes, MWC winemaker and general manager Eric Laumann says. He estimates that this year, 3,000 tons of grapes from all over California would undergo Flash Détente—roughly a third of the winery’s production. MWC’s unit can process 20 tons per hour.

At first, Laumann says, winemakers were “flashing” their grapes to reduce pyrazines. “Now they’re using it for everything,” he says.

“I’ve never seen anything as transformative as this technology,” says winemaking consultant Barry Gnekow, who has used both the French and Italian equipment.

The Flash Détente equipment is manufactured by Pera, based in Florensac, in France’s Languedoc-Roussillon region. The process involves a combination of heating the grapes to about 180ºF and then sending them into a huge vacuum chamber, where they are cooled. The cells of the grape skins are burst from the inside—the audible pop, pop, pop—allowing for better extraction of anthocyanins and skin tannins. Because this takes place before any alcoholic fermentation, the more bitter tannins, particularly seed tannins, aren’t extracted. (Because the seeds don’t contain water, they don’t explode.)

Flash Détente, which translates roughly as “instant relaxation,” also creates steam that goes into a condenser, and the condensate is loaded with pyrazines and other aromatic compounds. “Anything with a low boiling temperature will blow off,” Laumann says.

Because vapor has been removed, the sugar level is increased in the remaining must by about 6%. The winemaker can work with the higher Brix level, add back the condensate, discard the condensate and add water or a combination. Most discard the “flash water.” Smell the condensate and you can see why: Flash water from a load of Cabernet Sauvignon at MWC had a very light pink color and a greenish, acetone aroma.

    Exhaust, biscotti and Black Angus 

    In his work with flash extraction during the 2010 vintage, winemaking consultant Barry Gnekow also discovered something unexpected: The characteristics of the flash water can tell winemakers a lot about the area surrounding a vineyard.

    A load of Pinot Noir from Carneros produced flash water that smelled like car exhaust; the vineyard is next to a highway. Malbec from Ripon generated flash water with aromas of almond biscotti; there’s a flood-irrigated almond orchard next door.These are components in the grapes, Gnekow says, “that we didn’t know were there.”

    Then there was the load of Amador County Zinfandel that produced particularly nasty flash water. “We voted it as the worst flash water of the vintage so far,” Gnekow says. He subsequently found out that the vineyard is surrounded by grazing Black Angus cattle.

    Gnekow has been saving flash water and plans to visit the vineyards to check out their surroundings. “You know that what’s in the air gets in the grapes,” he says.

When the flash process concludes, the must has been cooled to 82º. Then the winemaker has two choices for fermentation. The grapes can be pressed and the juice (after clarification through filtration or a centrifuge) fermented, similar to a white wine. Or, the must can be sent to a tank for a more traditional fermentation with the pulpy skins, usually for five to six days.

Della Toffola’s Thermoflash unit at Lodi Vintners, a custom-crush facility in Woodbridge, Calif., uses similar technology, although the process for heating the must is slightly different and the system is more compact. The Lodi Vintners equipment, which the winery owns in partnership with Hahn Estates, can process about 30 tons per hour. Lodi Vintners general manager Tyson Rippey estimates that 4,000 tons would be run through it in 2010. Rippey says he’s looking at getting a smaller Thermoflash unit—about half the size of the one in Woodbridge—for Carneros Vintners in Sonoma, Lodi Vintners’ sister operation, in time for the 2011 vintage. Carneros Vintners operated a mobile Della Toffola unit with a capacity of about one ton per hour toward the end of the 2010 vintage.

Rippey says the total cost of the Thermoflash in Woodbridge was about $1 million, including installation and infrastructure. Laumann estimates that the Pera equipment, including infrastructure—plumbing, electrical, etc.—was about $2 million.

Paul Clifton, winemaker at Hahn Estates in Monterey County, has battled pyrazines in his red Bordeaux varieties for years. He says that when he and Gnekow first tasted a French Merlot that had been flashed, they also tasted the condensate, which he describes as “pure veg.”

“Barry and I looked at each other, and we just thought, ‘My god, this is the key.’” Clifton subsequently put all his 2009 Merlot through Flash Détente, after October rains forced him to pick earlier than he wanted. “It saved our Merlot program,” he says. He also used it for Merlot in 2010.

Laumann says he’s seen the best results on Cabernet Sauvignon and Pinot Noir, and Clifton has used it on both. Clifton says he was “blown away” by the results on Cabernet from a high-quality vineyard. “I wish I would’ve put more through it.”

As for Pinot Noir, he has flashed fruit from Lodi and from Monterey County, working in both Woodbridge and King City. Clifton has experimented with several methods of vinification, post-flash. “The stuff that we fermented on skins was really intense,” Clifton says. “As a blending tool, it’s an excellent option to have.” He has also tried adding unfermented Pinot that was pressed right after being flashed to a tank of Pinot that was being fermented traditionally. Although the wine was still fermenting when we talked, he was pleased with the early results, saying that it had good Pinot mouthfeel.

Flash technology differs from traditional thermovinification, because the traditional method doesn’t involve a vacuum (no exploding grapes), and there is no flash water produced as a byproduct. Winemakers familiar with both say the tannin extraction with thermovinification is also less. Laumann says that flash does everything thermovinification does, and does it better, in addition to removing pyrazines. “I’m not using (other thermovinification) very much anymore now that I have flash,” he says.

Some fear that use of flash extraction may lead to the loss of varietal character, although several winemakers mentioned that flashing the grapes seems to intensify fruitiness. It’s a question that researchers at the University of California, Davis, have been studying, using samples from Monterey Wine Co.

Linda Bisson, professor of viticulture and enology at UC Davis and one of the researchers working on the project, says they are looking at what characteristics are lost or retained by grape variety. They are also looking at the character and structure of tannins in flashed wines. Bisson is particularly interested in the effect of flash on Pinot Noir.

Researchers have collected samples of the original must, the flash water and the must after flashing, and they will also analyze wines post-fermentation. The analysis is ongoing, but Bisson says that based on some preliminary sensory analysis, she thinks the process results in more intense but less complex fruit characters. In Pinot Noir, she says, flashing amplifies spiciness but reduces the intensity of any floral notes.

And Bisson adds that even if the end product is less complex, “you’ve gotten rid of the negative stuff.” She suspects that some volatile components will come back eventually, if they exist in a bound (or glycosylated) form. But pyrazines don’t exist in that form.

From red to purple
During a harvest-time visit, Laumann pointed to a tank of Monterey Wine Co. Pinot Noir. “This is our marketing tank,” Laumann says. He had sent oak dust through the flash process with the grapes—which, he says, helps stabilize the color—then fermented the grapes on the skins. He’s shown the wine to a number of winemakers. “Just the color shift” from red to more purple tones “gets them going,” Laumann says.

We tasted several samples of flashed Pinot. One, which had been pressed and fermented without the skins, showed a lot of sweet, nouveau-style fruit. Laumann called it “a fabulous blending component.” Another sample, which had been fermented on the skins, was dark and structured, but its flavors were unmistakably Pinot Noir.

As for the color, Bisson notes that a stable purple hue in Pinot Noir “in today’s market is not a disadvantage.” Laumann adds that winemakers looking to enhance the color in their Pinots can flash part of the blend and make a wine that is 100% Pinot, rather than adding a percentage of, say, Syrah. “Who is more of a purist?” he says.

“I would rather have (flashed Pinot) as a blending tool than use Syrah,” says Hahn’s Clifton.

French research indicates that Flash Détente not only accelerates and increases the extraction of anthocyanins, but wines that have been subjected to the process also hold their color longer.

Given that flash technology is so new in the U.S., winemakers are still trying to figure out its best uses. “Everyone wants a recipe, but that can’t happen yet,” says Rick Jones, a winemaking consultant who is working with Della Toffola.

In its early years in Europe, the equipment was used primarily for lower quality grapes with problems that needed to be “fixed.” Flash offered the benefit of consistency by mitigating the effects of a bad vintage. But use of the technology gradually expanded, and proponents like Gnekow argue that “it’s applicable to all levels of the business.”

Winemakers still learning
Pyrazine reduction is an obvious use, as is intensifying color in certain reds. It could perhaps be used to create fruitier styles of wine. At this point, winemakers are still learning which grapes will benefit from the treatment and tweaking of fermentation techniques to get the desired results.

Gnekow says he’s used the process on overripe grapes to remove a raisined character. He didn’t think initially that flash technology would remove those flavors. He says, however, “I have the flash water to prove it.”

He has even used flash—thought of primarily as a tool for reds—on Chardonnay and says it seemed to intensify the fruitiness.

“You start discovering all these different options,” Clifton says.

Turning flashed grapes into a standalone wine is a possibility, but most winemakers see it as a tool for creating blends. As Bisson puts it, “It’s something on your spice rack to blend back with.”

But it’s not a panacea. Flash extraction won’t produce stellar wines from bad grapes. “It’s not loaves and fishes. You can’t create something that isn’t there,” Gnekow says.

Instead, like other winemaking technologies, it’s a useful tool for specific vintages, specific vineyards and even specific wine programs.

“It’s an adjunct to traditional winemaking,” Jones says. “It’s not a replacement for traditional winemaking.”

A resident of the Santa Cruz Mountains, Laurie Daniel has been a journalist for more than 25 years. She has been writing about wine for publications for nearly 15 years and has been a Wines & Vines contributor since 2006.

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Posted on 05.05.2011 - 06:03:49 PST
Has anyone experimented with flash detente for smoke tainted fruit?
Julia Sevenich
San Rafael, CA USA