Fermentation: The hottest ancient technique in restaurantsFermentation: The hottest ancient technique in restaurants

Bold, sometimes spicy, with a touch of umami and a funky (in a good way) flavor unlike any other, fermented foods have been bubbling up on restaurant menus for a few years now. Chefs smitten with the age-old process and the unique flavor it imparts to foods are using it to make everything from sauerkraut and salumi, to kimchi and hot sauce.

“I love everything about fermentation,” said A.J. Voytko, chef at The Original Dinerant in Portland, Ore. “It’s fun. It adds that depth. There’s that tang. It’s a little umami.”

While Voytko has long featured a variety of in-house fermented ingredients at the upscale diner — from sauerkraut and Brussels kraut, to kimchi and kosher pickles — last year he began experimenting with fermenting his own hot sauce.

Inspired by a desire to re-use the 5-liter barrels in which the restaurant makes its barrel-aged cocktails, Voytko started by fermenting small batches of habanero peppers for a few months at a time and using them in blue plate specials, chicken wings and mignonette for oysters. He felt it was such a superior product to commercially made hot sauces that last fall he decided to try it on a larger scale, fermenting red Fresno and habanero peppers in a full-sized bourbon barrel for a full year. When the bourbon barrel-aged hot sauce matures at the end of October, Voytko plans to bottle it and place it on every table.

The in-house fermented butter served at Orchids at the Palm Court at the Hilton Cincinnati Netherland Plaza. Photo: Hilton Cinncinati Netherland Plaza.

“Fermenting brings back everything your grandparents did,” Voytko said. “It’s just going to taste a whole lot better.”

For the last year or so, Todd Kelly, executive chef and director of food and beverage for the Hilton Cincinnati Netherland Plaza, has been incorporating fermentation into a number of dishes at the hotel’s fine-dining restaurant, Orchids at the Palm Court, as well as its bar and grill. He started by fermenting butter for the restaurant’s bread and butter service at all three concepts.

“[Fermenting] is a unique flavor profile that you can’t get from anything else,” Kelly said. “It changes the whole dynamic.”

Since then, Kelly has been fermenting just about everything he can get his hands on. Over the summer, he put up about 1,000 pounds of cabbage that will become sauerkraut and kimchi in a few weeks, and he has hot peppers fermenting in a barrel that will turn into hot sauce in about nine months. Currently on his menu at Orchids is a duck breast with his bok choy kimchi, while the menu at the grill includes Buffalo-style sweetbread “wings” made with his 2015 barrel-fermented hot sauce.

Chef Justin Severino is also putting a heavy focus on fermented foods at Cure, his urban Mediterranean spot, and Morcilla, his Spanish family-style restaurant, both in Pittsburgh.

“I cook from an historical perspective. I try to honor food traditions,” Severino said. “A huge part of that is fermenting.”

Kimchee Cornbread at Faith & Flower in Los Angeles. Photo: Faith & Flower.

Severino ferments between 300 and 400 pounds of salumi a week, as well as yogurt, cucumbers and radishes, and just about any vegetable in the brassica family. Among the fermented foods currently on his menu are a salumi board featuring 20 different cured meats, pickles and mustards, and a snack of lardo with spicy fermented radish, black garlic and crostini.

At Faith & Flower in Los Angeles, chef Walter Nunez is serving kimchi cornbread. An homage to LA’s Koreatown community, the brunch dish is made with a traditional cornbread batter, fresh corn, chopped house-made kimchi and Cheddar cheese, and topped with Korean chile flake.

“Fermented ingredients lend natural acid as well as savory flavors that come about because of the fermentation process,” Nunez said. “Adding something like kimchi rounds out the flavor with umami and brightens it up from the spice and acid.”

Chef Greg Garrison of Prohibition in Charleston, S.C., is also a fan of the acidity fermentation provides, and he likes to use it to add balance to his rich, Southern-inspired dishes. He’s currently serving black truffle polenta with oyster mushrooms, fermented mushroom Mornay and chanterelle powder.