Eureka, the experimenting proceeds. I am planning to do a Berliner Weisse and as it seems that the original Lactobacillus strain seems to be L. brevis for a Weisse. I did some research and found out, that there should be L. brevis in water kefir cultures. So I purchased myself a water kefir culture, and as I was already ordering I bought a Kombucha culture as well, and started my first water kefir today. Will post about my first Kombucha as well.
The kefir recipe was pretty simple: two table spoons of sugar, two table spoons of raisins and some lemon juice to 1 L (0.26 gal) of cold tap water and added the water kefir culture. Thats all. I used a big mason jar as a fermentation vessel.
Water kefir culture (white) and raisins (brown)
The fermentation should take about two days. Since there was not much work involved, I just took some pictures of the culture in the jar. The white stuff are the kefir culture, the brown stuff are the raisins. Really looking forward to tasting the kefir.
And of course, I will take some microscopic pictures of the culture in the future. And in my mind is the thought of a beer fermented with a kefir culture as well… Stay tuned.
01/26/2012: Kefir day. Started the fermentation.
01/30/2012: Tasting
And the microscopy pictures can be found here.
Eureka Brewing 
Hmmmm interesting. Actually kefir is soured milk. I think it’s more commonly known as buttermilk in the western world. Of course now they have all sorts of flavored kefirs, but the original is buttermilk. So if you really want to go authentic and can get your hands on real milk (not what we have in stores here in States) you just leave it sitting on your table overnight and you’re pretty much done 🙂 We used to do that back when I was a kid.
I’ve been toying with an idea of getting some yogurt cultures, which in essence is just a collection of different Lacto strains, and using it in a beer – Berliner and a Saison (in conjunction with Brett of course so that all the Lactic byproducts can be turned into funky fruit and stuff). Funny thing is that I’ve seen them sold a ton of times in local stores, but as soon as I want to buy one I can’t find any. There is plenty of unpasteurized yogurts here that are just loaded with Lacto-bacterial goodness so I might give it a try and streak some yogurt if I can’t find anything in local Chinese and Russian stores. It may actually be even more interesting that way.
My Kefir guy had two different cultures, one for milk and one for water. And since I don’t really like milk at all, well, thats why I went for the water kefir culture instead. I would have to check first, if all the lactose in the milk would be fermented since I am lactose intolerant.
I guess your idea with the yogurt culture may work. Actually there is a discussion on the http://www.homebrewtalk.com/f127/lactobacillus-brevis-297662/ about different strains and methods for a Weisse. Will brew myself a Berliner Weisse next week with isolated Lactos from acidified malt. But please post about your Yogurt Weisse.
Edit: Will taste the kefir today and post about it.