One interesting aspect of kefir is that most of the products prepared commercially in the United States and much of the world are not made using traditional kefir grains. Instead they are made using starter cultures consisting of some of the known organisms that are part of the traditional kefir symbiosis, but not all of them, and without the complexity and resulting unity of kefir's evolved life-form. A few reasons for this are cited in the literature. One is the slow increase in the size of the kefir grains, resulting in limitations on expanding production. Another is the difficulty of producing a consistent product due to the complex microbiology of kefir grains. In addition, the alcohol present in kefir -- which definitely has the potential to increase above the 0.5 percent maximum level for non-alcoholic beverages -- can create regulatory and legal challenges, as we have seen with kombucha.