Kefir

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Kefir grains, which are used to make kefir

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Various Russian commercial kefirs

Kefir (alternately kefīrs, keefir, kephir, kewra, talai, mudu kekiya, milkkefir, búlgaros), purportedly from either the Turkish "keyif" (joy/pleasure) or "köpür" ((milk) froth, foam), is a fermented milk drink that originated with shepherds of the Caucasus region, who discovered that fresh milk carried in leather pouches would occasionally ferment into an effervescent beverage. It is prepared by inoculating cow, goat, or sheep's milk with kefir grains. Traditional kefir was made in skin bags that were hung near a doorway; the bag would be knocked by anyone passing through the doorway to help keep the milk and kefir grains well mixed. Dairy-free alternatives are available, such as coconut milk kefir and soy milk kefir.

Marco Polo mentions kefir in recounting his travels.

Overview

Kefir grains are a combination of bacteria and yeasts in a matrix of proteins, lipids, and sugars. This symbiotic matrix forms "grains" that resemble cauliflower. Many different bacteria and yeasts are found in the kefir grains, which are a complex and highly variable community of micro-organisms.

Traditional kefir is fermented at ambient temperatures, generally overnight. Fermentation of the lactose yields a sour, carbonated, slightly alcoholic beverage, with a consistency similar to thin yoghurt. Kefir fermented by small-scale dairies early in the 20th century achieved alcohol levels between 1 and 2 percent, but kefir made commercially with modern methods of production has less than 1% alcohol, possibly due to reduced fermentation time.

Variations that thrive in various other liquids exist. They may vary markedly from kefir in both appearance and microbial composition. Water kefir (or kefir d'acqua) is grown in water with sugar (sometimes with added dry fruit such as figs, and lemon juice) for a day or more at room temperature.

Production

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90 grams of kefir grains

Production of traditional kefir requires kefir grains which are a gelatinous community of bacteria and yeasts, mainly containing various microflora such as Saccharomyces kefir, Torula kefir, Lactobacillus caucasicus, Leuconnostoc species, lactic streptococci as well as lactose-fermenting yeast. Kefir grains contain a water soluble polysaccharide known as kefiran that imparts a rope-like texture and feeling in one's mouth. Kefir grains cannot be produced from scratch, but the grains grow during fermentation, and additional grains are produced. Kefir grains can be bought or donated by other growers. Kefir grains appear white to yellow and are usually the size of a walnut, but may be as small as a grain of rice.

Health and nutrition

Kefir has antimutagenic and antioxidant properties, as shown in two different model systems.

One can change the nutrient content by simply fermenting for shorter or longer periods. Both stages have different health benefits. For instance, kefir over-ripened (which increases the sour taste) significantly increases folic acid content. The title of one study (funded by Lifeway Foods) claims that kefir also aids in lactose digestion as a catalyst. However, the study only shows that there is simply a lower amount of lactose in kefir than in whole milk. The lactose still had an effect on the lactose-intolerant adults involved in the study. The kefiran in kefir has been shown to suppress an increase in blood pressure and reduce serum cholesterol levels in rats.

Consumption

Some find kefir too sour on its own and prefer to add flavors or sweeteners. Frozen fruits can be mixed with kefir in a blender to make a smoothie. Kefir is sold with different varieties of fruit and flavors already added, both in the organic/ecologic and non-organic varieties. It is a breakfast, lunch and dinner drink popular across all areas of Russia, Belarus, Bosnia and Herzegovina, Ukraine, Hungary, Romania, Moldova, Poland, Norway, Sweden, Finland (especially with Russian and Estonian minorities), Latvia, Estonia and Lithuania where it is known as an affordable health drink. It is drunk the same way as milk, often accompanying pastries and other sweets. In Serbia kefir is consumed at any time of the day, especially with zelnik (zeljanica:Serbian), burek and banitsa (gibanica:Serbian), as well as in cold summer soups). Kefir, known as "yogurt de pajaritos" (bird's yoghurt), is also commonly consumed in Chile, where it may have been introduced by any of the various waves of migrants from the former Ottoman empire and migrants from Eastern Europe. The health benefits of kefir have recently made it more popular in the U.S. It can be found at Trader Joe's & Whole Foods grocery stores, as well as at Green's Organic and Natural Market in British Columbia, Canada.

Different milk types

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A glass of kefir in a Polish cafe

Kefir grains will successfully ferment the milk from most mammals, and will continue to grow in such milk. Typical milks used include cow, goat, and sheep, each with varying organoleptic and nutritional qualities. Raw milk has been traditionally used.

In addition, kefir grains will ferment milk substitutes such as soy milk, rice milk, and coconut milk, as well as other sugary liquids including fruit juice, coconut water, beer wort and ginger beer. However, the kefir grains may cease growing if the medium used does not contain all the growth factors required by the bacteria.

Milk sugar is, however, not essential for the synthesis of the polysaccharide that makes up the grains (kefiran), and studies have demonstrated that rice hydrolysate is a suitable alternative medium. Additionally, it has been shown that kefir grains will reproduce when fermenting soy milk, although they will change in appearance and size due to the differing proteins available to them.

Culinary uses

Kefir is one of the main ingredients in Lithuanian cold beet soup šaltibarščiai (Polish chłodnik), commonly known as cold borscht. Other variations of kefir soups and foods prepared with kefir are popular across the former Soviet Union and Poland. Kefir may be used in lieu of milk on cereal or granola.

See also

• Ayran
• Buttermilk
• Doogh
• Filmjölk
• Kumis
• Lactobacillus acidophilus
• Lassi
• Matsoni
• Tibicos
• Viili
• Yoghurt

Further reading

• Katz, Sandor Ellix (2003). Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods. Chelsea Green Publishing Company. ISBN 1931498237. 

External links

• Zoogloea.com Kefir Making.
• Videos About Kefir
• Fermented Foods: Kefir, from the National Center for Home Food Preservation
• Dominic N. Anfiteatro's kefir site
• Feedback from Dominic N. Anfiteatro's Customers
• Where to get kefir grains (listings by area)
• Source of free kefir grains - worldwide.
• Finding kefir
• Probiotic composition and therapeutic aspects
• Source of kefir grains in New Zealandar:الكفير (مشروب فوار)

zh:克非尔