The Mongolian Horse Milk Origins Of Sour Cream

The name sour cream sounds a bit like a mistake. Cream is supposed to be fresh and sweet. If it's sour, that means it's gone off, right? Surely, that's not appetizing. And yet, a loaded baked potato without a dollop of sour cream is a lonely baked potato indeed. And, what else could possibly accompany the humble green onion when flavoring potato chips?

Sour cream is an extremely versatile cooking staple, that can be used in both sweet and savory dishes. It's a perfect mix-in for silky mashed potatoes and is a Martha Stewart-endorsed ingredient for better banana bread. 

But how did this wonderful substance come to be? Was it a French dairy farmer's chance discovery? A method devised in ancient Greece with sheep's milk? Or did it come from hardy goat farmers on the Anatolian steppe? The answer, it turns out, is none of the above. The first iteration of sour cream was an alcoholic drink rather than a condiment and, instead of being made with sheep, cow, or goat's milk, this boozy beverage used milk from a horse. 

Koumiss or kumiss, also known as airag, is a mildly alcoholic drink that comes from fermented mare's milk. Mare milk is richer in lactose than cow or yak milk, which gives it laxative properties and makes it a poor choice for drinking raw — imagine what happens to a lactose intolerant person after a bowl of dairy ice cream and multiply it by 10. (Don't worry — there are tons of excellent non-dairy ice creams on the market today.) However, if mare's milk is fermented, the lactose becomes lactic acid, which makes it easier on the tongue as well as the stomach.

Koumiss was first developed by the Botai, an ancient culture of nomads in what is now Kazakhstan. As the use of horses spread across Europe and Asia thanks to the conquering Mongols, the drink traveled along with it. Herodotus, the ancient Greek historian, described the Scythians (another group of horse-riding nomads) making koumiss by thrusting a tube into a sensitive part of the mare's anatomy to force the udder down for milking. The milk was then left to ferment and was stirred regularly to help evenly spread naturally occurring bacteria throughout the batch, giving koumiss its distinctly sour flavor. 

As the Mongols conquered vast swaths of Asia, they brought their culture — and their food –- with them. But of course, not everyone lived like the Mongols. Some people, like the Russians, preferred to stay in one place rather than roam the land. As such, they had fewer horses and more cows. But hey, milk was milk, and the Mongols had managed to make something pretty tasty out of an otherwise undrinkable product. Just think of what the Russians could do with something much milder, like cow's milk.

Eventually, the Russians decided to tweak the koumiss-making process. The cow's milk was still fermented but Russian producers let it sit for longer, meaning that alcohol didn't develop. The result wasn't a drink, but a thick, tangy cream with a delightfully complex flavor. The Russians called it smetana (in fact, they still call it smetana), and it began to spread across Europe, eventually becoming the sour cream we know and love today.