Winemaking is about more than just grapes. They need something else to ferment into alcohol: a microscopic fungus, yeast. People have been fermenting grapes for thousands of years using wild yeasts that grow in the vineyard. Researchers at Washington State University want to know more about these species.
“We really don’t know much about what the wild yeasts are contributing,” Dean Glawe says, “But traditionally in Europe, even today, winemaking uses indigenous yeasts.”
Glawe, a recently-retired professor of plant pathology at WSU, was involved with the research.
Wild yeasts can be unpredictable, so winemakers today often use commercially-grown species. Those strains are usually members of the species Saccharomyces cerevisiae, a robust and alcohol-tolerant yeast. Many wild species can’t tolerate alcohol as well, or reproduce as quickly.
This means that S. cerevisiae present in a winery can kill off wild yeasts, even when they’re added. But…
“We have good evidence that a bunch of these wild yeasts persist to fermentation,” Glawe says. “Sacchromyacies takes over, but they’re still there.”
And even if wild yeasts don’t survive, they can still ferment sugars and have an effect on the final product. This unpredictability is “part of what’s fun about wine,” according to Glawe.
“Winemaking is much less of a science than beer making,” Glawe says.
“Whatever you feel it is, it’s certainly a combination of things,” Charlie Edwards says. “It’s one of the few things out there in the world where you’re mixing science, art, craft…”
Edwards, one of the researchers, is a food science professor at WSU who studies wine. The team is still working to learn the effects of different yeasts on wine, including the 60 new yeasts they’ve discovered in Washington vineyards. Yeast choice can change the flavor, alcohol content, and even the mouthfeel of wine. They hope to give winemakers more tools and a greater understanding of the microbes they work with.
“Have we found the ultimate super-yeast that can transform all wines into incredible experiences? Not yet,” Edwards says. “But we’re getting far closer.”
“Even on a product as old as wine, we’re still learning new things,” says Glawe. “For scientists, that’s a really fun thing. You can make contributions to something that old.”
Glawe says it’s these unknowns that make yeast so exciting.
“The basic fundamental and important thing that people don’t realize is that we still do not know much about the fungi that we live with all the time. With every breath you inhale about 50 spores,” says Glawe. “Any live organism has yeasts on the surface. People have a lot of yeast on them. … We get all excited about illegal aliens, but here we are living with these things and we don’t know what they are.”
Dean Glawe retired shortly after giving this interview. His part in the research as principal investigator was taken on by WSU adjunct professor Pat Okubara.
Copyright 2015 Northwest Public Radio