Kefir. 173 



into milk, together with ordinary lactic acid producers, living in 

 symbiosis with yeast, form granules which grow to raspberry sized 

 clumps and nodes. Sponge-like masses of ruffle-like appearance, 

 the so-called Kefir kernels result, in which are included the neces- 

 sary varieties of microbes. In dried condition these kernels are of 

 the size of millet seeds, but after treating with warm water or warm 

 milk they swell and proliferate in the milk up to the size of a fist. 

 The small young kernels are the best, as the larger readily degen- 

 erate, become slimy and crumbling as compared with the elastic 

 granules of more recent development. In order that they may again 

 produce good Kefir they must be subjected to treatment by 

 washing, drying in the sun, etc. The Kefir kernels may be 

 purchased. 



The origin of the Kefir kernels, that is the microbe colonies 

 which are clumped in the kernels, is not known, but the primary de- 

 velopment may have some connection with the method of ferment- 

 ing milk in containers made out of goat skins. 



If it is desired to prepare Kefir it is necessary to first obtain 

 the kernels which may be purchased. The Kefir kernels are 

 allowed to soak in boiled or lukewarm water, and then they are 

 transferred several times (3 to 5 times) from one warm milk into 

 another, the milk being poured off every 3 or 4 hours. 



The utilizable Kefir kernels increase in size during this time 

 through further swelling, and as a result of becoming lighter in 

 weight through absorption of carbonic acid they rise to the sur- 

 face of the milk, whereas kernels in which one of the varieties of 

 microbes for some reason or other became destroyed and degener- 

 ated remain on the bottom of the vessel. If the degenerated variety 

 of microbes recover through longer treatment with raw milk, and 

 if the proper relation of symbiosis again appears, then these ker- 

 nels are satisfactory for the production of Kefir. This condition is 

 manifested by the kernels rising to the surface of the milk after 

 some days. 



If a tablespoonful of these kernels is added to about one-half 

 liter of milk and this is allowed to stand for from 8 to 12 hours 

 at 14 to 18 deg. C., with frequent shaking, then a primary or mother 

 Kefir is obtained, from which through further fermentation in 

 corked bottles the Kefir may be prepared ready for use. 



The ''millets of the prophet," the Kefir kernels, are strained 

 through a sieve, and the homogeneous fermented milk is filled into 

 bottles, or from the strained fluid a considerable quantity is poured 

 into a bottle, to which boiled milk cooled to about 20 deg. C. is 

 added. The bottle is then closed and allowed to continue to fer- 

 ment for from 24 to 28 hours, at from 12-15 deg. C. In this 

 process the casein and serum separate but may be readily homo- 

 genized by shaking. The Kefir is then ready for consumption, 

 and represents a thick, sour, aromatic fluid of a pungent taste, 

 with a remarkable nutritive value. 



A similar product is prepared by the nomadic population of 



