In order to successfully make milk kefir beverages, here are some helpful tips & tricks:
a young kefir (fermented 12h to 24h) is slightly laxative, therefore indicated against constipation for e.g. The kefir is not very thick yet, it has some little bubbles and its taste is not very pronounced;
a medium kefir (fermented 24h to 48h) has already bubbles, it becomes thicker and the taste is comparable to a yogurt one;
a mature kefir (fermented 48 h to 72 h) slightly constipates, and it is rather used in cases of diarrhea.