Beer Brewers Worldwide Yearn for Wild Yeast

Once upon a time, shortly after Europeans began sailing back and forth from the American continent, a little fungus also known as wild yeast found its way into the crypts of Bavarian beer-brewing monasteries.

It quietly mixed with the existing brewer's yeast that had for centuries defined the beer drank across the European continent—a tradition passed down from ancient Mesopotamia—and gave the world the gift of the light, smoother lager beer. But hardly anyone was aware of what happened in that fermentation process, so when scientists were finally able to analyze lager yeast they were left to wonder: where on earth did half of the lager yeast DNA come from?

The mystery was finally solved in 2011 by a team of Argentine scientists led by Diego Libkind, who ventured into the Patagonian forest to study yeast when they stumbled upon an area that gave a strong scent of alcohol.

They called it Saccharomyces eubayanus to distinguish it from the brewer's yeast scientific name of Saccharomyces, informed the scientific world of their earth-shattering discovery via conferences and a study, and sent a strain of the wild yeast to the Westerdijk Fungal Biodiversity Institute in the Netherlands, for safekeeping.

The institute, which describes itself as a renowned microbial biological resource center of living filamentous fungi, yeasts and bacteria, holds the world's largest collection of yeasts. It also happens to be located just a few hours' drive away from the headquarters of the world's second-largest beer manufacturer.

This photo taken in March 2018 shows the branch of a tree in Argentina's Patagonia region featuring the wild yeast fungus. Newsweek

Heineken Global Brew Master Willem van Waesberghe told Newsweek the company had already begun thinking about experimenting with different yeasts—beer's long-overlooked component, while hops and malt and barley got all the attention—when Libkind's study landed on their lap, prompting them to brew the strain sent to the institute.

It worked right away. "It was sheer luck" he said, as yeast contains hundreds of different strains, and not all of them are suitable for brewing. "We succeeded in immediately fermenting the beer."

While others beer manufacturers have been experimenting with different variations of their trademark product, van Waesberghe loved the Heineken lager the way it was. "To me, it's perfect," he said. Until the wild yeast came along, the only alternative to Heineken's lager was the alcohol-free version—and the "oud bruin" low-alcohol version only available in the Netherlands.

But when he tasted the beer the Saccharomyces eubayanus' strain had produced, van Waesberghe's realized there was space in his heart to love another kind of Heineken, what would become known as H41, Heineken's first Wild Lager.

It took two years for Heineken to perfect the process of brewing the lager on a large scale. H41, which is available for sale in selected locations in the U.S., U.K., Italy and the Netherlands, features the same ingredients as the Heineken lager with the wild yeast being the only difference, but its flavour is starkly different.

Heineken's H41 is part of a wider, increasingly popular trend of experimenting with wild yeasts. The first result when typing "wild beer" into Google is a British producer called, as one may expect, Wild Beers Co. The business started in 2012 driven by the desire to experiment with different yeasts, setting up their whole brewery for that purpose. The company's co-founder Andrew Cooper told Newsweek that, while the company hasn't used the Patagonian kind yet, yeast does not have to come from afar to be wild. "We harvest yeast from our local environment, from fruit skins quite often," Cooper said.

Some beer makers who may just casually want to experiment with wild yeast strains can also obtain them from specialized laboratories. A wild yeast, Cooper said, does not necessarily stop being considered wild because it comes from a lab rather than occurring naturally. "The way [wild yeasts] work is so different from traditional brewing yeast and the flavour compound they create is very different," Cooper said.

Heineken's H41 could not have happened without Libkind's team permission to use the yeast for commercial purposes. Heineken was not the only beer manufacturer vying for the rights to use the yeast strain in their production but, Libkind told Newsweek, it was the one that showed most interest in the wild yeast's exceptional story and committed to giving it justice. The name of the beer, H41, was chosen in honor of the latitude in which the yeast was discovered.

Heineken's H41 wild lager is pictured in its natural habitat, near the city of San Carlos de Bariloche, in Argentina's Patagonia region in March 2018. Newsweek

Heineken, in turn, decided to work together with Libkind to foster research into the field beer-making and support Argentine brewers. The company also allowed Argentine beer makers to experiment with other wild yeast strain, as Heineken's moving on to other parts of the world, namely the American Blue Mountains and the Himalaya, to find the wild yeast needed for its next products in the Wild Lager series.

Libkind, who from hardly drinking beer has become an expert brew master, is overlooking the construction of a new research facility dedicated to the study of yeast and beer technology scheduled to open its doors in the Patagonian town of Bariloche by mid-2019.

Bariloche was already a hotspot for beer production thanks to its pristine waters and hops cultivation in a country known for producing grains like wheat, barley and malt. "This yeast completes the picture. We are working with the brewers to make the 100 percent Argentine beer, and also the 100 percent Patagonian beer in the future," Libkind told Newsweek.

A country mostly known for its wine, beer making in Argentina exploded in recent years. "The production has been growing in terms of styles, varieties, and innovation from both the big breweries and crafts," Alejandro Berlingeri, executive director of the country's brewmakers trade association Cerveros Argentinos, told Newsweek in an email statement.

According to him, one of the challenges facing local producers is increasing their market share by continuing to use innovate and use natural ingredients in production processes so their beer, consumed in moderation, can be part of a healthy lifestyle and diet. Berlingeri thinks the creation of Bariloche's new research institute will help local brewers. "It's important for Argentine beers and their reputation," he said, adding: "The great growth of craft breweries has to be accompanied by institutions that collaborate in the scientific development." For the wild yeast that once hid in the crypts, it's time to enjoy some time in the limelight, and under the microscopy.

Sofia Lotto Persio traveled to Argentina courtesy of Heineken.

Editor's pick

Newsweek cover
  • Newsweek magazine delivered to your door
  • Unlimited access to
  • Ad free experience
  • iOS and Android app access
  • All newsletters + podcasts
Newsweek cover
  • Unlimited access to
  • Ad free experience
  • iOS and Android app access
  • All newsletters + podcasts