I do not bother making my own, but I buy several quarts of the plain unsweetened kefir each week from Trader Joes. I mix around 75% water and 25% kefir and I drink this all day long. I consume around a quart per day along with the gallon of water. It has done wonders for my stomach and intestines. I highly recommend it to everyone. P.S.: if you have any burning or reflux from drinking espressos, then drink this before your espressos. The drink some more a half hour later.
My kids drank a lot of kefir in Russia and said that the plain unflavored variety made by Lifeway (available in many groceries here) tasted most like what they remembered. It is bubbly, but not too yeasty tasting.