Fermented foods have been part of the human diet for a millennium. Alcohol, bread, and cheese have been ubiquitous for about the last 15,000 years. Fermented foods declined in the Western world as it became more industrialized, though they are now reentering mainstream American culture due to a shifting focus on people’s gut microbiomes and the influence of social media.

To fully understand this article, one needs to know what fermentation is. Noma defines fermentation as altering food through microorganisms. A person well-versed in biology would define fermentation as the controlled breakdown of a substance into its constituents by various strains of fungi or bacteria. The word “fermentation” was derived from the Latin infinitive fermentare, which meant “to leaven.” The modern English word came about in the 14th century and has since been defined as microorganisms breaking down sugars into alcohol, acid, and gas. The root ferment diffused to nearby European states and Romance languages. It later spread to various African and Asian languages, as well as to the Americas during the Columbian Exchange, due to the dissemination of Western scientific knowledge.

One of the earliest examples of fermentation appears in Homer’s Odyssey, where the Cyclops Polyphemus leaves sheep’s milk in barrels, allowing it to ferment. Ulysses, upon arriving, eats the salty substance, which rejuvenates him. Polyphemus’s cheese later became known as feta. Early in civilization, fermentation was the primary method of food preservation, allowing people to extend the growing season. This remained the case until about the 17th century. Fermentation practices spanned cultures. The Romans made garum, a fermented fish sauce and precursor to modern fish sauces. South Indians created idli, a soft steamed cake, and dosa, a thin, crepe-like dish, both made from fermented grains. Koreans developed a wide array of fermented products, such as kimchi, to endure their extreme growing seasons. Eastern Europeans brewed kvass, a tangy, mildly alcoholic drink made from rye. These traditions persisted until industrialization, which ushered in technologies like canning, refrigeration, and ultra-processed foods, ultimately diminishing the need for fermentation as a preservation method.

In recent years, fermentation has undergone a sort of Renaissance. This revival is due in part to studies and documentaries highlighting the positive correlation between consuming fermented foods and improved gut health. Social media has also played a role in popularizing various ethnic fermented foods, making them mainstream. Fine dining establishments like Noma and Momofuku have contributed to this trend, with fermentation playing a prominent role in their cuisines. Noma, for instance, emphasizes sustainability and traditional Nordic values, including freshness and zero waste, and its chefs René Redzepi and David Zilber published The Noma Guide to Fermentation. I recently received this book and highly recommend it; much of the information in this article comes from it.

Fermented foods offer numerous benefits for both consumption and preparation. They support gut health, improve nutrient availability and absorption, and even enhance mental well-being. Fermented foods are rich in beneficial bacteria that support the gut microbiome—a colony of bacteria in the digestive system that aids digestion and other bodily functions. Consuming fermented foods can help the good bacteria outnumber harmful ones, reducing issues like bloating and gas. Fermentation also makes foods easier to digest. Enzymatic activities during fermentation break down complex fats, carbohydrates, and proteins into simpler components like fatty acids, sugars, and peptides, which reduces digestive discomfort.

Beyond their health benefits, fermented foods are versatile in cooking. For example, lacto-fermented foods, which are easy to prepare and require minimal equipment, yield both the food itself and a flavorful brine. Kimchi is a great example: its brine can be used to make vinaigrettes, dipping sauces, or even to deglaze mushrooms for a Korean-inspired duxelles. The kimchi itself can be added to fried rice, stews, or soups. Fresh kimchi works well as a garnish or snack, while older, well-aged kimchi lends depth to soups, compound butter, or savory glazes. Fermented foods, when thoughtfully incorporated, can act as all-purpose seasonings. For instance, I recently made a batch of lacto-fermented tomatoes and have been using the tomato water in sauces, soups, and stews. It’s salty, acidic, slightly sweet, and packed with umami. Adding just a little to tomato soup gave it extraordinary depth.