Kisiel Porridge Recipe

Invite microbes into your kitchen to create flavorful foods and keep fermentation traditions alive.

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by Sandor Katz
Though traditional grain ferments have waned in popularity, they’re nutritious and easy to make.
1 quart oat milk and 4 to 6 servings porridge SERVINGS


  • 2 cups oats, rolled, cracked, or milled into flour
  • Pinch of salt


  • Soak the oats in about 1 quart water, in a loosely covered container.
  • Stir, smell, and taste the soaking liquid daily to monitor the evolving flavor. I’ve gone as long as 5 days, at which point I detected notes of coconut.
  • When you decide it’s ready, strain the soaking liquid from the solids. Enjoy the flavorful and nutritious oat milk raw.
  • Transfer the soaked oat solids to a pot, cover with 4 cups fresh water, and add a pinch of salt. Bring to a boil, then gently simmer over low heat, stirring frequently to prevent burning on the bottom of the pot, until liquid thickens.
  • Enjoy your porridge with sweet or savory seasonings, as you prefer. (I love mine savory, with butter, peanut butter, miso, and garlic.)

Fermentation is a global phenomenon, and people in every part of the world use fermentation in similar ways. Fermentation is a strategy for safety, producing acids, alcohol, and other byproducts that prevent pathogens from growing. It makes many foods more flavorful and underlies the flavors of chocolate, vanilla, coffee, bread, cheese, cured meats, olives, pickles, condiments, and so much more. Fermentation extends the life span of cabbage and other vegetables (sauerkraut and pickles), milk (cheese and yogurt), meat (salami), and grapes (wine). The most widespread form of fermentation is the production of alcohol, from every carbohydrate source imaginable. Fermentation also enhances nutrients and makes them more accessible, and it breaks down many plant toxins and anti-nutrient compounds. Certain ferments, eaten or drunk raw after fermentation, provide potentially beneficial bacteria in great density and biodiversity.

Elaborate microbial communities populate all the plant and animal products that comprise our food. There is, therefore, a certain inevitability to microbial transformation. Cultures around the world have made use of this inevitability, developing techniques that effectively guide microbial transformation, not only in the context of food, but also in agriculture, fiber arts, and building.

Yet far from a unified set of techniques, fermentation encompasses a wide array of distinct processes and manifests in different ways in different places, depending upon which foods are abundant, the climate, and other factors. Tropical ferments are altogether different from the ferments of the Arctic. Even when environmental differences are not so stark, the ways people use microbial activity vary from place to place. Witness the diversity of cheeses, all made from milk. Because human migration and cultural cross-pollination have always been constants, others’ practices and techniques influence people everywhere. Like seeds, domesticated animals, culinary techniques, or any aspect of cultural practice, fermentation spreads.

Fermentation may be universal, but cultural continuity is not. Around the world, colonization has wiped out entire demographic groups and displaced others onto unknown landscapes. I have spoken with people unable to find information about their ancestors’ traditional fermentation processes because the cultural traditions from which they’re descended were destroyed, disrupted, or displaced. Cultural continuity is frequently disrupted by facets of modern life, such as urbanization, specialization, and mass-produced food. Cultural practices, wisdom, languages, and beliefs disappear every year. Fermentation practices must be used in order to maintain relevance and stay alive. We must cherish and celebrate the diversity of fermentation practices around the world, and document and share them.


The most fundamental technique for fermenting grains is simple: Soak them. Bacteria and yeasts are naturally present on dry grains, but they’re dormant in the absence of water. This is true whether the grains are whole, cracked, or finely ground, so long as they’re raw. When grains are soaked, dormant organisms awaken, metabolize nutrients, and reproduce.

Porridges and gruels are among the most widespread applications of grain fermentation, found across all civilizations born of grain agriculture. Unfortunately, these traditional grain ferments have long waned in popularity, eclipsed by baby foods, sugary cereals, and other processed foods that render porridges and gruels unappealing to kids, despite superior nutritive content.
I love oat porridge and gruel. Porridge is thicker and more substantial; gruel is thinner and soupier. They both feel so wholesome and deeply nourishing for me – especially when fermented. Their nutritional profile contrasts sharply with processed breakfast cereals, which are nutritionally deficient, high in sugar, and potentially harmful over time.

Fermented oats have many different regional names. In Estonia, a beverage called kile was made of oat flour mixed with water, then left in warmth for a night. This filtered sour beverage was consumed instead of sour milk on the side of the meal. If the filtrate was boiled, it became a kind of gruel, which was also called kile, but also kiisel or kisla, and eaten hot with butter or fat or, later, as a cold jelly. The boiling procedure took a long time at slow heat and required constant mixing; it had to meet an exact standard of sourness. Similar gruels (also similarly named) were prepared from rye or from rye and potatoes. In Belarus, lacto-fermented gruel was called kisiel, but a semi-liquid fermented dish from the oat flour was called by the same name. It was eaten with poppy or cannabis milk and is now, as in Estonia, recognized for historical use only.

Inspired by this description, I began experimenting. And because my maternal grandparents, Sol and Betty Ellix, came to the United States from Belarus, I adopted the Belarussian name kisiel for this sour oat milk and porridge. Both the oat milk and the porridge are compelling in their deliciousness. Time frame: 2 to 5 days, depending upon temperature and taste preference.

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