First, let’s get one thing straight: water kefir is NOT milk kefir. Not only does water kefir not contain milk, but the two use different grain types.
The “grain” used is actually a collection of bacteria held together with polysaccharides (carbohydrate molecules). Don’t worry though! These are the good bacterias. The resulting mixture looks a bit like a bunch of jelly-like crystals, or “grains”.
It’s thought that water kefir originated in Mexico, where they collect the bacteria off the leaves of the Opuntia cactus, use it to make a drink called Tepache with pineapple, brown sugar, and cinnamon. Other places of origin have been suggested as Tibet, Caucasus, and Ukraine.
Now water kefir is across the globe! You can find it in Germany under the name of Plitz, in France it is Les Graines Vivantes, and in Italy it is called Kefir di Frutta. Water kefir has many other names in English as well: tibicos, Japanese water crystals, California Bees, Australian Bees, African Bees, Ginger Bees, Ginger Beer Plant, Sea Rice, and Aqua Gems.
And that’s a brief history of water kefir! Thanks to Cultures for Health for their article the Origins of Water Kefir (http://www.culturesforhealth.com/learn/water-kefir/origin-water-kefir/).