Water kefir is similar to kombucha in that it relies on a SCOBY (symbiotic colony of bacteria and yeast) to ferment a carbohydrate rich liquid into a probiotic elixir! Drinking sweetened water, juice and coconut water cultured by water kefir grains is a great way to incorporate gut healthy beneficial bacteria into your diet.
Unlike kombucha which requires additional steps and can take over a week to finish, water kefir grains are simply added to a sweetened liquid and ready in 24-72 hours! After the initial fermentation, the grains can be removed and additional flavorings can be added before the product is bottled for the secondary fermentation which gives the fizz you are familiar with in other cultured beverages.
The internet is full of water kefir information and recipes. The book "The Art of Fermenation" is a great start!
How to make water kefir (1 gallon batch):
1/4 tsp baking soda
1 tsp molasses
1/2 cup cane sugar
1 gallon water
water kefir grains
Mix all ingredients aside from the grains. Make sure the water is warm enough to dissolve the sugar but NOT hot. Add the kefir grains, cover with clean dish or paper towel and secure with a rubber band. Allow to sit for 1-2 days in a warm location, cooler locations will work but it will take longer for the grains to consume the sugars. If you aggitate the container slightly you should see bubbles rise to the surface and the grains should have doubled.
Test the water kefir and see if it is to your liking. If you would like it less sweet, let it ferment longer. If you would like to add flavorings, remove the kefir grains and move your water kefir into "secondary fermentation" vessels such as mason jars and add in whatever you would like (juice, lemons, ginger, etc). Seal the jars with the mason lid and leave at room temperature for another 24-48 hours. This secondary fermentation will create the effervescence you've experienced with store bought kombucha. CAREFUL when opening, sometimes the secondary fermentation goes gang busters and you'll end up with a geyser and/or broken glass! Move to the refrigerator to slow down fermentation. Enjoy!