No one to date has been successful in producing kefir grains themselves, and
therefore new kefir grains can only be obtained by the propagation of existing grains.
Few sources of kefir grains exist today, and although kefir drink can be found in
many countries, grains are not commercially available. It has not been possible to
establish whether all existing grains have a common origin. Koroleva cautioned
that any attempt to replace kefir grains by pure microorganism cultures would not be
effective because the unique composition of kefir grains that has evolved over time
cannot be replicated or replaced. Any symbiotic relationships between bacteria and
yeasts that have developed over time would be difficult to replicate.