Sour Beer, yoghurt, and bacterial strains.

In general, probiotic organisms fall into four categories when considering using them for souring:

1. Good choices
2. Probably don't matter
3. Avoid under some circumstances
4. Avoid at all cost

Species which "probably don't matter" are those which are unlikely to grow in wort; either because the homebrewer lacks the ability to lower the oxygen level in the wort to the point where these organisms grow, or because wort isn't nutritionally compatible with these species. The flip side is that if these organisms grow, they should do the same thing as Lactobacillus - i.e. sour the wort while producing minimal off-flavours. So that's why they probably don't matter - they're not likely to do anything, but if they do end up doing something, they will help your wort sour. Included among these are:

1. Bifidobacteria sp. (again, sp means "any species")
2. Streptococcus thermophilus
3. Leuconostoc sp.

http://suigenerisbrewing.blogspot.ca/2015/07/choosing-right-probiotics-for-souring.html

 

I have not had any issues, and I have used yogurt containing it on a few occasions now. Also, many of the PNW kettle sours are made using Nancy's yogurt, and it contains S thermophilus. I have recently made the move away from yogurt to single strain Lacto plantarum pro-biotics.

 

I believe that in the United States, all yogurt must be fermented with S. thermophilus (as well as other microbes). That doesn't mean there is any viable S. thermophilus left in the yogurt when you buy it, but my guess is that anyone who has used yogurt to culture up souring bugs has used S. thermophilus. So people who have achieved good results with yogurt have probably achieved good results with S. thermophilus.

 

I make Skyr at home and am always left with tons of whey. This thread has me thinking I could make a starter with it for my next berliner. Hell, maybe I'll use some liquid leftover from making sauerkraut!