Why not use milk- or water kefir instead? As far as I can judge, kefir does exactly the same, probably for a fraction of the price. I bougt a milf kefir strain for 6 euros (about 7 USD) and it only needs milk. After 1 to 1,5 day you have a fresh batch of kefir drink using 0,5 liter of biological milk (cost: 0,5 euro).…