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Celebrate wine: Consider the science in your stemware

Posted by c.mangiapani | February 16, 2018
Uncork. Pour. Swirl. Sniff. Sip. The first to cleanse the palate, the second to acclimate, and the third to analyze. But what exactly are we analyzing when we savor a sip of wine? As you enjoy your favorite vintage on #NationalWineDay, consider the science behind your sensory experience.

In Washington State University’s Viticulture & Enology Program, scientists and students alike research the many factors that contribute to a quality Washington wine. One of the most important? Yeast.

Turning grapes into wine relies on this essential element. Without yeast, those grapes become grape juice. But through the process of fermentation, the berries are transformed into one of the world’s most popular beverages.

Wild, natural, spontaneous, or selected, yeasts turn up on the winemaking scene in all manner of ways—and affect fermentation and the resulting wines in just as many. For instance, non-Saccharomyces yeasts (shortened to “non-saks” by the scientists) can improve mouthfeel of a wine.

“The texture of a wine in your mouth, that’s mouthfeel,” said Dr. Carolyn Ross, professor of Food Science at WSU. “We measure mouthfeel with a standard tool called a ‘Mouthfeel wheel,’ which compares sensory experiences, like touch, to the texture of wine on the tongue.”

So if a wine has a particularly high alcohol content, you might describe it as “hot.” Or maybe it’s highly tannic, resulting in a “gritty” texture or a “dry” feeling. These elements are produced, in part, by managing yeasts.

When combined with other yeasts, like Saccharomyces cerevisiae, “non-saks” can reduce the final alcohol content of wine—an increasingly popular method among Washington winemakers.

In fact, according to studies conducted in WSU wine microbiology labs, Merlot showed reduced alcohol content when the fermenting winegrapes were inoculated first with non-saks and then later with Saccharomyces cerevisiae.

These deliberate, science-based decisions made by vintners add up to a singular sensory experience. Whether you’d describe your favorite wine as “full-bodied,” “silky,” or “smooth”—that’s science.

Thirsty for more? Read about WSU V&E research, the V&E Program, and the state-of-the-art Wine Science Center.

Scientist sliding a wine and survey through a window.
Dr. Carolyn Ross prepares a sensory evaluation of wine in the WSU Sensory Laboratory in the School of Food Science at WSU-Pullman.
Circle diagram with colored slivers.
Developed by Gawel et al. in 2003, the “Mouthfeel Wheel” is a standard tool used by wine sensory scientists like WSU’s Carolyn Ross.
Three scientists, one looking through a microscope.
Dr. Charles Edwards, left, analyzing wines with graduate students.