Water Kefir is a fizzy probiotic drink. A lot of people think of it as a healthy homemade soda pop replacement. It is basically fermented sugar water. The kefir grains (which aren't grain at all, but actually yeasts and bacterias) work to eat the sugar converting it into simple sugars that have probiotics, higher vitamins (because they are made more easily digestible) including hard to get B vitamins. For a much better explanation check out this website, or google Water Kefir. There is also a Milk Kefir that you use with Raw Milk. This is not that.
Water Kefir in the quart jar on the right, has been fermenting for 24+ hours. It is pretty forgiving. My house was pretty cool today so I let it go a little longer. On hot days it may not need all 24 hours. But it is hard to mess up. More than 48 hours and you risk starving the grains though. On the left are swing top bottles, like these. You don't have to use swing tops. You can reuse beer bottles, if you buy extra caps and a capper, you can reuse store bought kombucha bottles or you can use another quart mason jar. I have found that the swing top bottles and the beer bottles create the most fizz. And sometimes if you use kombucha bottles they become hard to open, due to the pressure build up. Do not use plastic bottles. It's handy to have a funnel and you'll need a small strainer. Plastic is recommended, but since the grains don't stay in it long, I use metal. You want to keep your grains away from metal for the most part, I've read.Pour a bit of your favorite juice in the bottom of each bottle. This is a cherry juice. My favorite is grape. If it is a lighter flavor juice I add a bit more (like the cherry above), grape I use a bit less. Experiment to your liking. Citrus juices are not recommended, although some people like to put a slice of lemon. Ginger also works well in kefir. You can also use fresh fruit instead of juice. Berries work excellently. Strawberry kefir is delicious!
Pour your kefir over your juice, carefully straining the "grains" out.
Pour the grains back into the quart mason jar you use. You don't have to wash this out too often. And when you do, make sure there is no antibacterial soup residue left behind. (It'd kill the kefir...)
For one quart of kefir you want to use 1/4 cup of grains and 1/4 cup of sugar. For most batches I use organic cane sugar. Sometimes I do half organic cane sugar and half succant. Kefir thrives on the succant, but it has a stronger flavor in my opinion so I don't use it as often. If your grains ever get a bit sad (they take too long to ferment, they aren't getting as bubbly, they start to get very, very small) use sucanat and or 100% pure blackstrap molasses (just a bit) to perk them back up. They need the minerals that plain white/cane sugar doesn't provide.
This time I did half cane sugar and half sucanat.
Another way to perk up your grains or to help them multiply faster (so you can have more than 1 quart going or so you can share with a friend) is to add a few drops of this concen trace mineral drops to them. I bought this at Amazon over a year ago and still have most of the bottle. A few drops will do fine and not every batch. (It's also good to add a few drops to your drinking water if you've been sweating a lot.)
Add filtered water and shake to distribute the sugar. I use a Britta filter. It's important to remove the chlorine, which will kill the kefir.
Set on your counter and ignore for 24 ish hours. In hot weather I will sometimes put the flavored (second fermented kefir) in the fridge after 12 hours. Otherwise after 24 hours it is also ready to be refrigerated. One clue for you to check is when you see small bubbles at the top of your juice. And then you can start the process all over again.
*** Important to note. If you need a break from your kefir or you are going out of town, just get to the step where you are about to leave them on the counter to ferment, but instead, stick them in your fridge. They will keep for weeks like this and I think you can even rescue them if you forget about them for several months. If you are planning on taking a several month break from them, you can dehydrate them. I have not done this myself, but have heard of plenty of success stories.
If you just have them in fridge storage, when you take them out, depending on how long they've been in the fridge, they may be ready to pour on juice or may need to sit out for a bit. You can tell by how fizzy and the smell once you get some practice at it. ***