Based on what I’ve written on the subject of fresh-fermented dairy so far, you might be tempted to think that bacteria are the only microbes that can ferment milk. This isn’t so. There are a few oddball varieties of yeast that can do it too. What difference does yeast make in a yogurt culture? Quite a lot as it happens. For while the waste product of lactose-eating bacteria is acid, the waste product of lactose-eating yeast is…anyone? Anyone? Yes you at the back with the hangover. Right: alcohol.
And in fact there are quite a few Central Asian fresh-fermented yogurt drinks that are alcoholic. Kumis is probably the most famous of these, a mildly carbonated, reasonably alcoholic drink made from horse milk. Why horse milk? Probably because back in the day, it was the only thing available to Central Asian nomads like the Mongols (famous and fearsome horse riders). Though by a very interesting coincidence horse milk also has more lactose (sugar) in it than the milk of other ruminants like sheep or goats. And more sugar in the milk means more alcohol in the kumis. Humans…so predictable.
Kumis is still extremely popular in Central Asia, in Russia and places like Kyrgyzstan, Kazakhstan and of course Mongolia. Though these days most of it is made with cow’s milk instead of horse milk. That’s partly because the Central Asian horse herd is small relative to the demand for kumis, partly because a cow is far less likely to kick your brains out your left ear when you try to milk it.
I confess I’ve always been very curious about real kumis, though long ago gave up hope that I’d ever taste the real thing. Who knows, though? I live in the heart of horse country nowadays. Maybe I should go buy a football helmet and give the horse-milking thing a try.
UPDATE: Reader Bronwyn from New Zealand adds:
The udder of the average nursing mare is also a great deal smaller than that of a dairy cow; the cow having been bred for centuries to give much more milk than needed by a single offspring.