This procedure can be used with any kind of juice or combination of juices. Most of the time I buy unfiltered organic juice- not from concentrate with no added anything. Everybody, including my grandchildren love this particular fermented soda. It's simple and easy.
I use one 2 L and one 3 L snap lock jars and three 1 liter snap lock bottles to carbonate. It takes 5 days to make 3L of soda.
1) In the 2L dissolve 3/4 cup sugar in a bit of hot water, fill with cold water not quite to the top, and when it's cool add your Kefir grains.
2) Let it ferment on the counter for 2 days.
3) Transfer the 2 liters of fermented sugar water to the 3L jar thru a strainer to catch all the grains.
At this point you will start the 2L jar all over again with step 1. Instead of fermenting you can put the jar with the sugar water plus grains in the fridge and put off starting a new batch for up to a week or so. If you do that, you will need to add a half day for the jar to acclimate from the fridge once you put it on the counter , so that would make the primary fermentation 2 and a half days if you do this. I pretty much do this every time because 3 L every 5 days is a lot.
4) Add 1 Quart of unfiltered apple juice to the 3 L jar. I have used filtered juice but prefer unfiltered.
Add 1/3 cup organic lemon juice
Add a cinnamon stick. You can break it up a bit but no powder.
5) ferment for 2 days. There is no need to burp either the primary or secondary jars.
6) transfer thru a strainer (to catch the cinnamon) into the three 1L bottles and leave that for 12-24 hours to carbonate. With regular store bought unfiltered apple juice it can carbonate easily in 12 hours. Check it after 8 hours and ALWAYS do that in the sink and open the snap lock slowly. In the early stages it will just fizz a bit. Reseal and check every hour or two to get it to where it sends bubbles up when you open it, but not so pressurized that it wants to push foam out the top. Try not to over carbonate. You'll get the hang of it in no time.
Refrigerate the 3 bottles. Always open the bottles in the sink first when it is full, and pour it like it was a beer so you don't have too much head.
It is a real treat . Enjoy !