It’s simply great to have a milk-Kefir culture on the boat. Those little cauliflower-shaped buggers turn milk over night into something very similar to yogurt–no special temperature required, no special procedure. I just throw a bunch of them into a jar with (stirred-up powder) milk, the creamier the thicker the resulting yogurt. About 12 hours later the yogurt is forming, but still a bit liquid and mild. 12 more hours in the cupboard and the yogurt has turned thick with the liquid separated below.
Depending on how thick/creamy I want, I stop the process sooner or later. I pour off the transparent liquid and strain the creamy part through a mosquito net into another jar. The yogurt slips through, the little kefir balls remain in the net.
I rinse them (still in the net) under running water, stir up a new cup of milk, throw them in and they get to work immediately again!
If I want to slow down the process, I put the milk jar into the fridge, there they still make yogurt, but take much longer.
If I want to take a break (e.g. when not on the boat) I put them into very watery milk, container into the fridge and they go to sleep until I wake them, rinse them, put them into creamy milk and let them play in warm temperatures again (you can tell that those easy-going, low maintenance thingies have something like a pet status on Pitufa 
)
Kefir is perfect for smoothies, yogurt dips and to replace yogurt in pies, etc. According to Wikipedia “milk kefir (to distinguish it from water kefir) or búlgaros, is a fermented milk drink made with a yeast/bacterial fermentation starter of kefir grains, that originated in the Caucasus Mountains of West Asia.”
