Our little 8-container yoghurt incubator works well for the Canadian bagged-milk situation. When I have one container left, I heat up a single bag's volume of milk (1.3 L) then let it cool. That volume plus the last container dumped in to inoculate the batch makes exactly 8 full containers again. A continuous loop.
Started some yoghurt and also some sauerkraut working over lunch time.
The yoghurt is about timing - remembering to start a batch before we use up the last of the previous batch – need it for culture.
The sauerkraut is just a process of massaging the chopped cabbage with salt and letting it sit for a few days immersed in the resulting liquid to ferment. No extra inoculation needed.