Finding the right yeast

Wines & Vines, Sept, 1989 by Andrew Martin

Finding the right yeast

It's one of those little ironies that you find throughout history. For centuries, the people who claimed to be making wine were completely unaware of the tiny organism that was actually doing the winemaking - saccharomyces.

In those days there wasn't much quality control, but wild yeasts were enough to turn the juice into wine, and that was all that mattered.

Now that we understand the role of yeast much better, it is easy to imagine the effect this natural approach must have had on the wine itself. Some vineyards, blessed with a better strain of wild yeast, might well produce a better wine, and in some vintages, a poor yeast crop could adversely affect a perfectly good grape crop.

And that was also before winemakers understood the effect of temperature on fermenting yeasts - a great harvest could be followed by an intense cold front, and the naturally cold fermentation would completely alter the character of the wine. No wonder there was more variation from vintage to vintage!

But now that Louis Pasteur has explained it all, the mystery is gone, and our little friend saccharomyces is nothing more than a docile servant to the all-knowing winemaker.

Well, not exactly.

Clayton Cone is a research biologist with Lallemand, Inc., Montreal, Canada. Lallemand began in 1923 as a producer of baker's yeast. To gain an edge on the competition, the company developed a research department which improved strain selection and process control.

"Like a lot of things in the wine industry, some of the biggest breakthroughs came in the 1970s" remembers Cone. "There was considerable interest in new wine yeast strains, and it seemed as if each winemaking region wanted to have its own strains isolated. And that continues today."

Lallemand's technical teams soon worked out an arrangement with a number of technical institutes in Europe to develop pure yeast strains for their winemakers. "It's fascinating process, and I think we learn something new with each new strain." says Cone.

"In many cases, these technical institutes provide the raw yeast to us, and we then isolate the strain. As a part of the marketing agreement, we then determine the best growing conditions and produce this pure strain in industrial quantities.

"It's a good partnership. Because it's their yeast, the institutes work very closely with us to insure quality control, and they use the royalties from the sales of the yeast to further improve the strain. It's a continuing process.

"Obviously, each of the twelve strains we currently market does something particularly well," says Cone. "For example, the EC-1118 `Prise de Mousse' is well adapted to a wide range of conditions, and has excellent organoleptic properties."

John Moynier, winemaker at the Charles Krug Winery, is using this yeast for its new barrel-fermented, sur lies Chardonnay. "The grapes are from our twenty year old vineyards in the Carneros, so they've got great fruit," says Moynier, "but we just weren't getting the character and finesse we wanted in the wine until we went with Prise de Mousse. It made a huge difference."

At first, many winemakers in California simply matched the grape variety to the yeast strain from the same traditional European region to make their wines. "We have pure strains from Champagne, Montpellier, Narbonne, Rhone, Bordeaux, and U.C. Davis," says Cone.

"Now some winemakers are going beyond simple regional guidelines, and really getting into the opportunities these yeast offer, both in terms of flavor characteristics and fermentation conditions."

Bruce Scott, of Scott Laboratories, sees the same kind of developments in the marketplace. "We have to have a wide variety of strains available to winemakers, and we see more experimentation in the cellars today," he says. "And, of course, people like Lallemand provide the kind of pure strains that allow the winemaker some control. That's a crucial part of the winemakers' experiments."

What's next?

Cone claims that the future is already here, with the so-called "Dominant Yeasts." "These are yeasts which actually enhance the purity of the fermentation by inhibiting growth of other yeasts which may be present. The result is a cleaner, more controlled fermentation. They might even reduce the amount of SO2 needed before fermentation.

Cone sees these yeasts as the wave of the future. "This is a result of more than twenty years of research. The first strain was selected by Pierre Barre of the Institut National de Recherche Agronomique. It was being used by several wineries which belonged to the Institut Cooperatif du Vin in Montpellier, and seemed to work well."

In 1978, Pierre Barre discovered that this "V86" strain was a dominant yeast, and as such, it possessed secondary qualities that make it even more attractive as a pure wine yeast. Barre asked the research department at Lallemand to isolate it and attempt to grow it in industrial conditions.

Cone's team was successful, and this yeast, the first commercially-available dominant yeast, is now in use in over 1,000 wineries in southern France.