Sourdough has exploded in popularity among home bakers. If you’re among them, you’re already flirting with the world of fermentation. But there’s so much more to explore.
Fermentation, by definition, is the process of chemical breakdown and subsequent transformation of organic matter by microbes. Kimchi, soy sauce, salami, sauerkraut, cheese, sake, kefir, kombucha and Champagne are all fermented products. These processes all date back thousands of years and are beloved for their purported benefits and ability to change and preserve ingredients.
“With fermentation, you transform flavors,” says Massimo Zitti, a co-owner of fermentation-focused cocktail bar Mother in Toronto. “From one ingredient, you can make four, all with different flavors and textures.” From lemons alone, savvy bartenders can make citrus salts, bubbly kombuchas, chips, syrups or preserved lemons. Mother doubles as a shrine to preservation and fermentation techniques, complete with a basement fermentation room, where bartenders continue to dutifully nurse sourdough starters and feed ginger “bugs.”
Zitti and his crew have some tips for those looking to explore DIY fermentation. The best way to begin is to “buy some jars and books and start failing,” says Zitti. His reading list includes “The Art of Fermentation,” “The Big Book of Kombucha.” "The Joy of Cooking” and “The Modern Cocktail by Matt Whiley.” After that, this is how to get into the world of fermenting.
Lacto-fermentation is the process of fermenting fruits and vegetables (think dill pickles and kimchi) with non-iodized salt. “It’s the easiest thing people can do,” says Zitti. “All you need are the ingredients, salt, something to seal them and a room, which can simply be a warmer place in the house.” Zitti notes that warmth does not equate to sun. Keep mixtures far away from direct sunlight, as it will increase the risk of spoilage.
Mother uses this process for plums, to give a tannic element to Negronis and add a vegetal note in a spirit-forward mezcal-and-sherry drink via lacto-fermented carrots. It’s a versatile process. When the bar was last open normally, “Everything we had we lacto-fermented: clementines, grapefruit, pineapple,” says Zitti. “Every single thing was really tasty.”
Zitti adds the peels of the fruit to a vacuum bag with salt. The Noma Guide to Fermentation’s master ratio is any weight of fruits and vegetables, plus an additional 2% of that weight in non-iodized salt. But lately, he has been playing with a recipe from fellow Toronto natives Supernova Ballroom that calls for more water. “When you add more water, you get more yield,” he says. “It’s great for citrus flavors, though I wouldn’t dilute sweet things, as you’ll lose a lot more flavor.” Nor would he try this with ingredients that naturally contain a large amount of water, like tomatoes.
2. Start a Starter
Ginger beers, sourdoughs and kombuchas all require starter cultures like a SCOBY (symbiotic culture of bacteria and yeast). When added to a food or beverage ingredient, starters will jump-start the fermentation process. Starters can be bought or made with a little patience. “You can create ‘bugs’ or ‘mothers’ with just fresh fruit and sugar,” says Zitti. The combination grows until frothy and “living.”
The time it takes for starters to grow to maturity will depend on the environment, temperature, dilution and how often you feed it. “Starters are like pets,” says Zitti. “When you feed it is important. Just like pets, if it eats three meals a day, it’ll grow like crazy. If you feed it less often, it will be thinner and not as strong, and it won’t want to do anything.” He recommends raw sugar over fine. “They need the calories!” he says.
3. Naturally Ferment
Natural fermentation, or acetic acid fermentation, is the method that births kombucha, water and milk kefirs, and ginger beer. “It’s basic fermentation: water, fruit and sugar,” says Zitti.
Ginger beer, the easiest, is the mixture of ginger bugs, ginger and sugar, while Kombuchas start as a sugary tea. When a SCOBY is added, the bacteria and yeast combination transforms the mixture into an effervescent and slightly sour beverage. (Does this process sound familiar? It’s similar to how sparkling wines and ciders are made.) Zitti warns that care and caution must be exercised with natural fermentation processes. “Bottles can explode,” says Zitti. Follow instructions and safety precautions carefully, and keep materials clean—bad bacteria can leach into ferments, halting or spoiling the process.
After this first fermentation, Zitti and crew use a second fermentation to flavor the kombucha and water kefir. Mother flavors them with apple and dill or maple during colder weather. Zitti often offers complimentary glasses to VIP guests, as acetic acid fermentation is surprisingly affordable: For roughly $2, Zitti can make gallons of kombucha.
4. Mix It All Together
These three processes act as a foundation for fermentation. Once you’ve mastered them, you can play with a range of flavors and further techniques and begin working creations into cocktails.
But part of the excitement of fermentation is that there’s no real way to master it. The ingredients are “living,” rendering perfect consistency impossible. Flavors and aromas will change slightly, or sometimes dramatically, every single day of the process. Zitti recommends tasting every ingredient each day to gauge how the process is unfolding. (Hint: Unpleasant smells can indicate things are going south.)
But the unpredictable can work in your favor. Zitti recalls discovering a batch of forgotten fizzing tepache in storage. “It’s amazing. It’s like a sparkling cider,” he says.
At Mother, the team is constantly experimenting. They add black garlic, for which they slow-cook garlic for a period of six to eight weeks to give it a balsamic vinegar-like flavor, to Irish Coffee and infuse gin with seaweed in a vacuum bag—never glass—for 24 hours. “Don’t cook the ingredients first,” says Zitti.
When employing your new products in cocktails, Zitti underscores the importance of maintaining balance. He cites a time he judged a cocktail competition. The contestant had made a beautifully fermented ingredient, but it wasn’t quite right for the cocktail. “What it needed was simply bitters,” he says. “We’re not fermenting for the sake of fermenting. We’re fermenting to make better drinks.”