500ml is only one US pint, not a huge amount. After all Kefir, whilst highly beneficial is still a food item. Years ago I used to be able to buy a natural goats milk yogurt in one litre tubs, and they would only last me a couple of days. Generally spread my consumption over the morning - half first thing and the rest with lunch.
Gave some grains to my MiL and showed her how to make kefir. After a few months asked how she was doing with it. She replied that she was now up to two tablespoons a day, which I thought was so funny. Quite certain that I get withdrawal symptoms if I don't get my daily kefir fix.
Alison
Rev Mother Bene Gesserit.
Sent from my PDP11/05 running RSX-11D via an ASR33 (TTY)