This delicious, cultured probiotic beverage has completely replaced my desire and need for any kind of carbonated soda. It is delightfully bubbly all on its own—it develops a natural effervescence during the second brewing, and it also retains some sweetness even as the fermentation process proceeds.
I have at least a couple of batches of this brewing in my kitchen at all times, and it even travels with us when we go on trips. It is the finickiest of the cultured beverages we make, and I have better success if I don't try to leave it too long or put it into dormancy.
MAKING WATER KEFIR
1) Acquire some active water kefir grains from a reliable source. A healthy set of grains is always multiplying during the culturing process, so you can ask a friend who makes it regularly, or you can order them through various online sources.
2) Prepare a sugar water solution in a wide-mouth quart jar by dissolving 1/4 C. organic cane sugar with a little bit of very hot water from your tap. Stir until dissolved, then fill the jar to near the top with room-temperature filtered water. (The total volume will now be 3-4 cups of sweetened water.)
3) Drain your water kefir grains from the previous batch and add them to the sugar water solution in your quart jar, taking care to only use about 1 heaping Tbsp. of kefir grains per batch. (When they have multiplied beyond this quantity, remove the extra grains to share with a friend or start another batch!)
NOTE: It is very important to use only plastic, mesh, and glass containers and utensils when handling and working with your kefir grains. Never use metal strainers, spoons, or other equipment when working with kefir grains. Remember, your kefir grains are alive and must be cared for properly to continue to thrive.
4) Cover the jar with a coffee filter or cloth secured by a rubber band. Set aside to culture in a warm spot (68-85 degrees F) for 24-48 hours.
IMPORTANT: If you are culturing other fermented foods in your kitchen, you must keep them in separate areas from one another. Milk, water, and juice kefirs can brew in the same area—though we do use different starter cultures/grains for each—but all kefir should be kept separate from other culturing foods (including kombucha, sauerkraut, sourdough, yoghurt, or cheese) during the fermentation process. Intermingling the different cultures by storing them near one another during the culturing process will yield some very unfavorable results in flavor and texture—or sabotage the fermentation process entirely, in some cases! Make separate fermenting areas several feet away from one another for culturing each of these probiotic foods and beverages.
Note that doing this may change the taste of your final product, as you are technically culturing the beverage for twice as long as usual before pouring it up and bottling it for the second fermentation. Although still delicious, this will result in a stronger, more sour-tasting beverage.
5) If you prefer your water kefir without the natural effervescence produced during the second ferment, you may pour it up at this point and drink it plain or with added fruit juice. However, we enjoy the carbonation produced in this next step, so we always continue with a second ferment under pressure.
FLAVORING AND BOTTLING WATER KEFIR
6) You can use a variety of flavorings for your second ferment, but the one that works best for us and which we strongly prefer is fresh grapefruit juice. Slice the grapefruit in half and remove any large seeds that are visible, then use a hand juicer to extract as much juice and pulp as possible.
7) Pour the grapefruit juice into your prepared kefir—this is the liquid you strained the grains out of earlier—and then skim off any tiny seeds that are in the mix using a miniature sieve. (Note that this sieve can be metal because it isn't touching any live kefir grains.)
Take care to leave as much of the pulp as possible. It is this juice and pulp that will feed the kefir during the second ferment.
NOTE: It is important to purchase Grolsch-style flip-top bottles designed especially to handle the pressure of fermented and carbonated beverages. (I purchase Lorina sparkling lemonade and then re-use these bottles for second fermenting our "freshca" soda, but you can order or purchase them from any craft beer store or online. Just be certain they're safe for brewing or they will explode on you!)
8) Carefully inspect your flip-top bottle for any signs of cracks. Finding none, pour all of the prepared kefir/juice mixture into your flip-top bottle and clamp it sealed.
NOTE: If you are using the small grapefruits that are about the size of a large orange, you will need the juice from the entire grapefruit. If it is one of those huge grapefruits with the thick skins, you may get away with just a half. At any rate, you will want to add just enough juice to the finished water kefir to bring the liquid level in your flip-top bottle to near the top. If you leave too much headroom, you may build up too much pressure and your bottle may explode. (I have done this. It is not pretty, and it is a huge mess of juice and fruit and broken glass to clean up from all over your kitchen!)
10) You can refrigerate it at this point if you do not want carbonation. If you do want carbonation, clamp the bottle securely and let it sit at room temperature for 24-72 hours or until it carbonates.
It is important to burp the bottle once a day to avoid excess pressure build up. Just open the seal and lift the cap ever so slightly and let the pressure release very slowly. (Otherwise your soda may "bubble up" out of the bottle and all over your counter. If it seems like it is going to do so, clamp the bottle shut again very quickly and move to the sink before opening again. Let just the slightest air out very slowly until the pressure has released enough to let go and open the bottle fully. When it is this fizzy, it is ready!)
11) Refrigerate your bottles of water kefir ("freshca" around here), and continue to burp them once daily until consumed. (I set a daily alarm on my watch so I never forget!)
12) Enjoy!
