A famous brewmaster and master chef bond over fungus in Patagonia. 
Francis Mallmann
Credit: Avant Garde Media

In 2010, Argentine yeast scientist Diego Libkind stumbled upon a rare mother yeast in the Beech Forest of Patagonia. It was this same discovery that paved the way for Heineken to create a Wild Lager series, featuring this newly discovered fungus.

“It’s a bit of hard work, especially in Anglo-Saxon communities and societies where yeast is not something which is known," says Willem van Waesberghe, Heineken's master brewer. "It’s mostly associated with diseases and hygienic situations. In Italy, every household has yeast. They have to make pizza dough, so you need yeast for that.”

While yeast may not be the first thing that comes to mind when hiking through stunning Bariloche, Argentina, the unattractive, tumor-like balls of fungus growing on the area's beech trees are responsible for a new beer: H41. (The name stands for Heineken and the latitude coordinate of the exact spot in the Beech Forest where said yeast was discovered). The brand is building the Latin America’s first-ever brewing technology center in Bariloche, allowing Libkind to continue research and for consumers to taste exceptional beers crafted from yeast growing in the wild.

Francis Mallmann
Credit: Avant Garde Media

“Yeast is one of the most beautiful things in the world,” says Francis Mallmann, a Patagonian chef best-known for reinventing the art of fire cooking. “We have it everywhere—in our bodies, we use it a lot for cooking and what we do with fire is quite primitive. What I use is all the techniques of fire that is related to the life of the gaucho, which is our cowboy, to the natives of Argentina and the influence of fire that came from Europe, mainly from Spain, through the Turkish influence.”

(The chef says that becoming friends with fellow yeast evangelist van Waesberghe was basically inevitable, although Mallmann admits it was “like a blind date” at first.)

In Bariloche, Mallmann cooks Lamb al Asador on a cross and beautiful, vibrant pit vegetables underground for several hours. The lingering aftertaste of the fire-cooked meat and vegetables is strikingly similar to the aftertaste of the beer. “What I feel with this beer is that it has this spicy, clove-like aroma and is also a little smoky,” says van Waesberghe. “The smoky part really fits well with barbecued meat.” Van Waesberghe once created Heineken bread at a pop-up bakery in Amsterdam to show off A-yeast (used to make the original lager). The bread, he noted, was a very wet bread, but still very fruity, showcasing the characteristics of beer.

Brewmaster Yeast
Credit: Avant Garde Media

“Yeast is a delicious thing, says Mallmann. “It’s basically a mushroom. “You can capture the yeast of a salami if you want. For chefs, yeast it is very important. I use it a lot for baking bread and for making desserts when we want a bit of sour taste. I think that our cooking is quite primitive and it’s very earthy and brutal in a way, so it’s related to that nature part of wild yeast.”

Mallmann’s chefs also take yeast very seriously. “They travel with their yeast everywhere,” he says. “They sleep with the yeast in the bed because it has to be at the right temperature or it dies.”

Cooking with beer is also a delicious way to add depth of flavor to a dish. “When you reduce beer in cooking, when boiling very slowly, it gives a very elegant bitterness to things I find, even sweet things,” says Mallmann. “I like the bitterness in some meats or apples. I love to cook apples in beer. I put apples in a big tray, I fill it with beer and put a huge stone on top and I put that in a wood oven—so as they cook, the stove flattens them and they destroy themselves and they drink all the juices of the beer that reduce as well. It’s very delicious and I serve it with a spoonful of cream.”

Ultimately, Heineken’s Wild Lager series will encourage brewers worldwide to experiment with yeast in the wild across the globe and demystify what yeast is all about. “H41 isn’t the only yeast that lives here [in the Patagonian forest]," says Libkind. “There are over 5,000 strains and varieties.”