Exploring the Art of Fermentation in the Kitchen From the Brewery to the Bakery
What is fermentation and why should we care?
The first question is easy, the second is not. Fermentation is the breakdown of a substance by bacteria or other microorganisms, like yeast. There are different kinds of fermentation, some familiar (cabbage into sauerkraut) and some less familiar (cacao beans into chocolate), but all involve microorganisms changing the chemical composition of the original substance. Why should we care, or eat, or make, our own fermented foods? There are all sorts of answers for all sorts of people.
Fermented foods contain living bacteria, and for some reason that gets us all squirmy, thinking that bacteria are dirty and bad. But think again! There are lots of good, necessary bacteria out there and human beings couldn’t function without them. They help us digest food, maintain regular bowel function, and balance stomach acids. Every human being actually contains more bacterial cells than human cells.
The health benefits of fermented foods are almost universally accepted, although Americans are a little late getting to the fermentation party. Whether it’s kvass in the Ukraine, kimchi in Korea, or kefir in the Caucasus, fermentation is a fascinating transformational process responsible for changing the flavors and nutrition of many different kinds of foods.
Fermented foods are considered easier to digest because the bacteria have already started breaking down the structure of the food. This leads to better, more efficient nutrient absorption. Many of the bacteria that ferment foods are also probiotics, defined by the World Health Organization as “live microorganisms that confer a health benefit on the host.” While the claims for probiotics range from strengthened immune systems to curing eczema, not all of these claims have been substantiated. However, it’s generally agreed that probiotics improve intestinal health.
AT THE BREWERY
Ethyl acid fermentation (when yeasts convert carbohydrates into alcohol) is probably the most familiar type of fermentation. It gives us wines and beers and cordials. The first stage of ethyl acid fermentation is aerobic, meaning the fermented food and yeast is exposed to air. After the initial, most vigorous fermentation, the liquid is moved into closed containers and the second stage takes place under anaerobic conditions (in the absence of oxygen).
Yeasts occur naturally on many fruits and flowers. That white-ish bloom on grape skins? It’s yeast. Flower pollens may contain yeasts, which allow them to ferment into light, bubbly cordials. Beer recipes also include yeast, but commercial brewers may pasteurize their beer to extend its shelf life and pasteurization kills microorganisms. However, sour beers (also known as wild beers) are not only unpasteurized, but also incorporate wild yeasts and/or bacteria. Please note that in this context, sour does NOT mean spoiled or bad. These brews are tart and tangy. Belgium has produced sour beers for centuries, including lambics, gueuzes and Flanders red ale, but it’s only been a few decades since American brewers have taken up the challenge. Earth Eagle Brewings in Portsmouth, New Hampshire, has been experimenting with sour beers and gruits (beers flavored with herbs other than hops) since they opened, and co-owner and brewer George “Butch” Heilshorn says that often the people who love sour beers aren’t traditional beer drinkers.
I had never acquired much of a taste for beer. I like it, but don’t usually consider it worth the calories. After one sip of the Earth Eagle gruit lineup, however, I realized that I love beer; I’m just not a big hops fan. Most modern beers are flavored with the female flowers of the hops vine. Hops have a bitter taste that balances the sweet malt grain and they also bring some preservative properties to the mix. If you don’t like the flavor of hops, you might think you don’t like beer. But Earth Eagle’s gruits are flavored with a range of plants and mushrooms, including locally foraged burdock and dandelion root, pine candles, spruce tips and chaga mushrooms. These beers are tangy and refreshing. If you want to try a truly sour beer, order a glass of Earth Eagle’s Sour Puss. Sour Puss is one of the most delicious brews I’ve ever tasted, and not at all what I expected. I was ready for a facetwisting, pungent blast of intense sourness, but instead was delighted by a round, complex tartness that slaked my thirst with a single sip and left me wanting more.
There are several ways to give sour beers their flavors. Lactobacillus or Pediococcus bacteria and Brettanomyces yeast are the most common agents used to sour beer, and beers brewed with these wild microorganisms can take years to mature. Acidulated grains produce a sour beer more quickly than microorganisms; they work by changing the pH of the brew. Spontaneous fermentation (where the beer is exposed to whatever microorganisms are in the air) is a third way of creating sour beers.
Because sour beers are mutable and unpredictable, there’s no guarantee they’ll be delicious. Conversely, they may surprise you with their unique and exciting flavors. Butch urged me to be open-minded to what turned up in the vessel and I wasn’t disappointed.
IN THE KITCHEN
Lactic acid fermentation (an anaerobic process) is another type of fermentation that works wonders in the kitchen. Lactobacillus bacteria tolerate very high salt levels, and that’s the key to its success. Lacto fermentation requires only salt, vegetables and water, and it works because the high salt content of the brine kills bad bacteria but allows the lactobacilli to thrive. Lactobacilli convert starches and sugars in vegetables into lactic acid and the resulting acidic brine preserves the vegetables and gives them a characteristically tangy taste.
Lacto fermentation is the process that produces real kimchi, dill pickles and sauerkraut. I say real, because there’s an important difference between fermented foods and pickled foods. Fermented foods are preserved by lactic acid, which is produced by the living Lactobacillus bacteria. Fermented foods are alive, and their flavors change with time, which means the kimchi you start today will taste different next week and different again the week after that.
A pickle is any food preserved in brine. All fermented foods are pickles, but not all pickled foods are fermented. Pickles preserved in vinegar brines and canned at high temperatures are not alive. The high heat kills bacteria, making most pickles just regular food instead of living food. It also gives them a substantial shelf life, which is essential for many traditional, commercial food manufacturers.
At Anju Noodle Bar in Kittery, Maine, Gary Kim (co-founder of Anju, Son-Mat Foods and the Wallingford Dram) cooks amazing food and answers questions simultaneously. Initially known for its kimchi and fermented hot sauce, Son-Mat introduced Seacoast residents to the spicy, funky, living flavors of lacto fermentation. The label on their bottles clearly states “this is living food” and informs consumers that bubbling is a natural part of the fermentation process, so please don’t be alarmed! A busy lunch service confirms that local eaters have embraced these flavors wholeheartedly.
Son-Mat’s hot sauce is a combination of sugar, salt, water and peppers, finely crushed and left to ferment for about a week. Kimchi paste (previously fermented) is added to the pepper sauce, delivering a double wallop of fermented flavor. It’s a little bit hot, a little bit sweet, and very tasty. Needless to say, I bought a bottle to take home. The spicy Napa cabbage kimchi is their signature condiment (yes, I bought a jar of that, too) and Anju serves it raw or cooked into okonomiyaki, a bafflingly delicious pancake combining pork belly, shrimp and kimchi.
While fermented foods are often raw foods, it’s possible to cook them after fermentation has occurred. The kimchi pancake is one example, and sourdough bread is another. Sourdough starter is alive. Baking kills the bacteria and yeasts, but their tasty memory lingers on.
David Anderson at Ceres Bakery in Portsmouth, New Hampshire, is passionate about baking bread. He loves its history, its cultural importance, and the fact that bread requires attention. It’s not a food you can assemble by rote or take for granted. It behaves differently depending on temperature, humidity and altitude. He explains that almost any bread could be made with a starter. (Silly me, I thought it was just for sourdough.) What sets sourdough apart is the length of time the starter is allowed to ferment. Bread yeasts and bacteria produce both lactic and acetic acid, but the long duration of sourdough fermentation results in the production of more acetic acid and a tangier, more sour bread.
Ceres has had its current sourdough starter for at least eight or nine years, but the bakery uses it more for flavoring than for leavening. David uses a tiny bit of the mother starter to create short-duration starters that ferment for about 24 hours, he then uses this fresh starter as the leavening agent in many of his artisanal breads. The results are complex loaves (from the ever-changing, living microorganisms), not restricted to traditional sourdough flavors. Playing with fermentation times and starter ratios allows David to create a multitude of wonderful breads with various textures and flavors.
Acetic acid fermentation is a third type of food fermentation and is an aerobic process. It plays a part in long-duration bread starters, but is best known as essential to making vinegar and kombucha. Both kombucha and vinegar rely on a globular film of cellulose, called a SCOBY (symbiotic colony of bacteria and yeast) for kombucha and a MOV (mother of vinegar) for vinegar. The difference is that SCOBY contains gluconic acid and MOV does not, but basically they serve a similar function, which is to produce acetic acid. In the case of kombucha, the SCOBY transforms tea and sugar into a fermented beverage, while a MOV transforms wine into vinegar. You can grow a mother in wine and a SCOBY in kombucha, but starting from scratch takes a long time. Adding a piece of an existing SCOBY or MOV as a catalyst to your tea or wine speeds up the fermentation process substantially.
So why, then, should we care about fermented foods? It’s entirely possible that kombucha will increase your energy levels and kimchi will improve your gut flora. Maybe sour beer will make your digestive system happier than it’s ever been before. Personally, I’m in it for the flavors.