We usually think of bacteria, molds, and fungi as unwelcome visitors in the kitchen, but in restaurants worldwide, chefs--famous and acclaimed ones at that--are using microbes to create new flavors, reveals Nature Microbiology.

Arielle Johnson, author of the article and a chemist by training, works with numerous restaurants, including Noma in Copenhagen, which is famous for its exclusive use of Scandinavian ingredients. Like Momofuku, Bar Tartine, Husk, and many other progressive restaurants across the world, Noma uses science to discover new flavors. Johnson's current focus is fermentation.

Fermentation is the process through which bacteria and fungi take ingredients like regular tea (kombucha), boring barley (beer), or plain ol' milk (c'mon we don't need to explain this one) and biochemically transform them into more flavorful foods. Although it's becoming part of haute cuisine, it's nothing new. For thousands of years, fermentation has been a key way of preserving raw food.

"Fermentation's always been a home thing," Johnson says. "But I think the sort of reinterpretation that's happening is opening up people to, I don't know, different ways of doing it, like more of a creative thing."

Typically, food gets its flavor either from the conditions it was raised under, or from the transformation to sugars and proteins during cooking. But when certain strains of bacteria come into contact with food under the right conditions, they can also create flavor. For example, cabbage, a relatively bland vegetable, is given a sharp zing when lactic acid bacteria breaks down its sugars to make sauerkraut.

Fermentation is ancient, but what is new is the way restaurants are using it, the article reports. At Noma, for instance, where chefs use exclusively regional ingredients, they cannot turn to lemons or grape-based vinegars to add tart notes to dishes. Instead, for that sour fix, they head to the lab.

Johnson and Lars Williams, Noma's head of research and development, run a lab out of four tricked-out shipping containers that make up seven climate-controlled rooms. They can dial the temperature down to -30 degrees Celsius or the humidity up to a drippy 99 percent to create conditions perfect for the various vinegars, misos, yeasts and fermented products they design. So when René Redzepi, founder of Noma, needs to add some acidity to a new dish, Johnson and Williams create it for him.

Fermentation is not just confined to the lab. Along with other DIY food trends, like canning, fermentation is currently enjoying a renaissance. There are Facebook home-fermentation groups, Instagram stars, and fermentation festivals. And while some things, like lactic acid fermentation, are fairly accessible (the USDA has even issued guidelines for safe home fermentation of fruits and vegetables), others, like misos or koji, require a bit more precision and knowledge. But Johnson believes that the type of cutting-edge and creative fermentation she and her colleagues are doing will make it out of labs and into kitchens in the near future.

"I think, if anything, fermentation's gonna become like less of an esoteric thing and... just sort of like an accepted part of the kitchen repertoire, kind of like how using an immersion circulator and doing sous vide was quite fringe ten years ago" she said.