Bubbly, slightly tangy, and milkshake-thick, milk kefir offers more than just a satisfying Epicurean delight. It’s also packed with a plethora of probiotic benefits, potentially more than any other dairy ferment. Kefir’s many benefits stem from its fermentation microbes — the kefir “grains.” These so-called grains are actually gelatinous, knobby, cauliflower-like clusters made up of a spectrum of bacteria and yeast housed in a matrix of their own making. This symbiotic community of bacteria and yeast — or SCOBY — is a self-replicating, fermentation-fueled milk miracle.
Marvelous Milk Kefir
Studies across the globe have determined that kefir grains contain an incredible variety of microbes. Compared with other dairy ferments, the biodiversity of these grains is truly unsurpassed, with some studies detecting more than 50 bacterial species and 14 fungal species housed within them. Each one of kefir’s microbes offers a separate health benefit, as well as a different flavor, texture, and aroma. Kefir grains provide what are known as “undefined cultures,” unlike the “defined,” or known, microbial cultures found in the powdered commercial versions.
Grains grow in different cluster sizes, from very little to quite large. When they replicate, a few will break off and grow to the same size as the cluster that produced them. The larger-sized grains must be handled with a bit more delicacy than the little ones if you want to maintain their impressive size. After the kefir grains break down the lactose sugars in the milk into glucose and galactose, these two simple sugars become available for the production of lactic acid. Meanwhile, grain microbes combine with glucose and galactose to form a gelatin-like polysaccharide matrix known as “kefiran.” In a few studies, kefiran has shown potential for anti-microbial, anti-inflammatory, and wound-healing benefits. So, don’t worry if you don’t strain all of the grains out of your glass of fresh kefir; just munch down any bits you missed!
Mysterious Milk Kefir
The origin of kefir grains remains a mystery, but for as long as memories and tales have been told, kefir grains and the fizzy beverage they create have been a prized food of the peoples of the Caucasus region, which is situated between the Black and Caspian seas. Considered a gift from the prophet Muhammad, kefir grains and their cultivation secrets were fervently guarded and prized as family treasures, and they remained largely unknown to the rest of the world until the 1930s.
In 1908, desperately seeking a cure for tuberculosis, Russian physicians seized the grains from their custodians through intrigue, spy craft, and extortion. They sent an employee of the Moscow Dairy, a beautiful woman named Irina Sakharova, to the Caucasus Mountains to charm away kefir grains from the region’s prince, only to be kidnapped by him. She wasn’t released until Tsar Nicholas II demanded the return of the woman, along with 10 pounds of kefir grains for the kidnapping crime. The grains were subsequently taken to the Moscow Dairy, and for the first time, kefir was commercially produced. By 1930, milk kefir was mass-produced across Russia, and the secret spread around the world.
Nowadays, true milk kefir largely remains the product of home fermenters and of small-scale creators because almost all of the mass-produced milk kefir is created using freeze-dried starter culture powders. In an effort to extend kefir’s shelf life and to eliminate the need to propagate kefir grains, starter cultures mimic the work of a SCOBY, but contain less microbial diversity. With a pinch of yeast, these starter cultures ferment to create a product akin to yogurt and cultured buttermilk, without the alcohol content traditionally present. Yet, fermenting your own milk kefir has magnificent merits, and it’s delightfully simple to make.
More than Mythical, It’s Versatile!
Cow’s, goat’s, or sheep’s milk — any dairy will do. As long as you’re brewing it on a regular basis, making a fresh batch of milk kefir is remarkably simple. Without feeding your kefir grains on a weekly basis, however, the number of microbes begins to decline. Some of them will outlast others, changing the resulting fermented flavor from a citrusy tang to a vinegary bite. If left unfed long enough, they’ll all die. If a break is needed, however, you can dehydrate or freeze the grains to extend their lives.
Kefir will thrive on any dairy milk — from goat’s milk, to sheep’s milk, to cow’s milk, and beyond. For the most consistent product, choose pasteurized milk, or heat-treat your own farm-fresh milk. You can use raw milk, but because kefir is fermented at room temperature, raw-milk microbes will likely out-compete the kefir population, potentially even starving them out. If you have some grains you really love but want to ferment with raw milk, it’s a good idea to keep a few grains fed separately using pasteurized milk. You can even use ultra-pasteurized milk, and milk with any fat content you like.
Read more about Kefir!
Excerpted from Homemade Yogurt & Kefir by © Gianaclis Caldwell. Photos by © Carmen Troesser. Used with permission from Storey Publishing.