Pour water into a glass jar. Add ginger, apple, raisins, and sugar. Stir well.
Add grains and stir with a nonmetal spatula. Close lid and store in a dark, dry place. Allow to brew for 48 hours. Pour kefir through a plastic sieve to strain fruit and grains. Remove the fruit from the cultures to stop fermentation. You can store the kefir grains in a small amount of kefir liquid in the refrigerator for up to a month. Store kefir in a glass jar at room temperature or in the refrigerator to keep chilled. Note: Metal will damage the kefir grains. Do not use any metal when making kefir.
If you don’t have coconut water, or you don’t want to make coconut water kefir, fruit kefir is also very easy and versatile. It is necessary to add cane sugar in order to ferment, but the kefir grain converts all of the sugar to healthy bacteria. The end result is not sweet. You can experiment with any dried fruit and flavors. Peach would be delicious to try in the summer!