Yeast is to winemaking what faith is to religion. Without that one essential element, the rest collapses. Today, tech innovations are letting vintners use yeast not as an essential ingredient but, rather, as a targeted tool in winemaking, depending on their goals.
Yeast is just one tiny fungus, but its metabolism enables grape juice to transform into wine. For thousands of years, the process was a mystery, but through trial, error and observation, cultures across the world began to grasp its essential function, if not always the mechanics of it.
Antoni van Leeuwenhoek got the ball rolling in the 17th century, when he observed yeast by itself for the first time, but it wasn’t until late in the 19th century that Eduard Buchner isolated the zymase, which carries out the fermentation process. In the following decades, scientists and vintners have been racing to learn more about the chemical reactions responsible for fermentation, and how they can — and can’t — be controlled to make tastier wine.
This task has taken on even greater urgency in recent years, as climate change transforms and threatens the future of winemaking. In May, Enoforum USA is hosting one of the largest technical-specific wine industry events in the world, bringing together hundreds of attendees, technicians, researchers and companies to share research and ideas, and find new ways to create and innovate better wine for consumers and the planet. We reached out to two of the presenters for a sneak peek of the latest developments in the always fizzing and frothing field of yeast.
Enartis Is Finding New Ways To Fight Climate Change
Climate change is posing an existential threat to wine production. Up to 56 percent of current wine regions internationally are projected to no longer be suitable for wine production if global temperatures rise by 3.6 degrees Fahrenheit by 2100, according to a study published in the Proceedings of the National Academy of Sciences. (With 7.2 degrees of warming, 85 percent of land currently growing grapes will be untenable).
Contending with this crisis will require an all-hands-on-deck approach, contends Jasha Karasek, a winemaking specialist at Enartis and an upcoming Enforum USA presenter. Karasek and his team are working with winemakers in regions already feeling the negative effects of climate change to help improve wine quality.
“Some of the biggest effects of climate change in warmer regions are that grapes and wines are developing lower acidity, higher Brix and higher PH levels,” Karasek says. “All of those things together can create higher alcohol wines, flabby flavors and issues with shelf stability.”
Karasek frequently hears from winemakers across the world who are having what they consider to be unusual fermentations; in particularly compelling cases, members of his team will go to the winery during fermentation and observe what’s happening, taking samples of the wine during fermentation.
Back at the Enartis lab in Windsor, Calif., team scientists will then isolate the yeast and figure out what it’s up to.
“Several years ago, we visited a winery making Amarone della Valpolicella, where grapes are harvested and then dried for several months,” he explains. “Crush and fermentation happens during winter months, and spontaneous fermentation happens with several yeasts playing a part. We isolated the cryophilic, or cold-loving species Saccharomyces uvarum and the Saccharomyces cerevisiae, and discovered they could help mitigate several of the issues winegrowers in warmer climates are seeing.”
In 2018, the company sold a blend, dubbed EnartisFerm ES U42, which lets winemakers produce wines with low alcohol, higher acidity and more intensely fruity and floral aromas. Last year, Enartis released an isolated strain of Sacchoramyces uvarum, finding that on its own, it produces similar results and, used with other yeasts, it can mimic the complexity that can come with native fermentations — but without any of the downsides.
“The reason indigenous or wild yeasts can produce such complex wines is because they’re often a blend of several yeasts,” Karasek explains. “And while it’s easier for smaller wineries to control how they develop, larger wineries don’t have that luxury, and so many things can go awry. By using Sacchoramyces uvarum and other commercial yeasts at the same time, wineries are able to lower their alcohol, raise acidity, stabilize flavors and shelf life, and create complexity, with more control and focused results, which you don’t get with wild yeasts.”
Climate change, he says, is the elephant in the room that the entire industry is trying to deal with.
“We’re excited that this yeast counteracts the effects of climate change, and we also see it as a small tool in combating the carbon footprint,” Karasek says. “Winemakers who want to raise acidity are often using organic additives that have to be flown in from Europe. But using our domestically produced yeast garners the same results. Compare flying a 50-pound bag across the ocean versus getting a 500-gram bag of yeast from us.”
Fermentis Is Finding Efficient Ways To Make Tastier Wine
At Fermentis, as at Enartis, the team is dedicated to finding modern solutions to distinctly modern winemaking problems.
Most winemaking throughout human history happened on a small enough scale to make constant supervision at every step of the process practical and feasible. However today, for many winemakers, production now happens on, for all intents and purposes, an industrial scale. Attempting to create consistent wines with an army of lively fungus recruits soldiering along behind you is no easy task for a vintner.
We’ve found that, for certain types of yeast strains, our E2U [Easy to Use] technology, combined with early inoculation timing, guarantees the achievement of the targeted type of wine,” explains Arnaud Delaherche, technical manager and oenologist at Fermentis by Lesaffre, and also a presenter at Enoforum USA.
Today, the use of active dry yeast requires a rehydrating preparation step, which is where the trouble often begins. “This rehydration step can have a negative impact on the implantation of the yeast in the must, resulting in undesired organoleptic profiles,” explains Delaherche.
In a bid for tastier wines and a smoother production process, the new E2U lets vintners use Fermentis yeasts in direct inoculations, with no rehydration required on the grapes or after settling.
“We have found that the yeasts can be inoculated with E2U at different times during the vinification process,” which provides flexibility and ensures predictable results, continues Delaherche.
We may never figure out yeasts completely. But with every discovery, we’re finding greener, easier ways to make better wines.
To learn more about these developments, register for the May 11 Enoforum USA 2022 conference in Sonoma County, Calif.
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Kathleen Willcox
Kathleen Willcox writes about wine, food and culture from her home in Saratoga Springs, N.Y. She is keenly interested in sustainability issues, and the business of making ethical drinks and food. Her work appears regularly in Wine Searcher, Wine Enthusiast, Liquor.com and many other publications. Kathleen also co-authored a book called Hudson Valley Wine: A History of Taste & Terroir, which was published in 2017. Follow her wine explorations on Instagram at @kathleenwillcox
