Home production of kefir is practiced in many countries, and scientific studies have
often used samples gathered from homes. The traditional method of kefir making is
performed by adding kefir grains directly, as a starter, to pasteurized, cooled milk.
In home production, fermentation temperature and time are not rigidly controlled.
The final product cannot be used to inoculate new milk to produce kefir because the
original balance of microorganisms in the grains has been disrupted; kefir grains are
essential to the process.