Kefir starter kits typically come in three varieties: milk kefir grain kits, water kefir grain kits and powdered kefir starter culture kits. Starter made from kefir grains can be used indefinitely, whereas starter made from kefir powder can only be used a few times, until the bacteria strains weaken.
Milk kefir grain kits come with milk kefir grains. The grains can be used to ferment dairy milk. Water kefir grain kits come with water kefir grains that can be used to ferment coconut water, sugar water or fruit juice. Powdered kefir starter packets can be used to ferment dairy milk, coconut milk or fruit juice.