There is a cold cucumber soup that uses kvass as its base. I would recommend giving that a try as well.
https://www.youtube.com/watch?v=ifE7gDiLDbE
The Life of Boris also has a great video on making Kvass:
https://www.youtube.com/watch?v=k1UTJKBMvgc
though I haven't gotten around to trying it, I've only had commercial bottled and canned ones. I imagine if you make it yourself you'll have a slightly more alcoholic outcome.