Like so many facets of life in Europe of the Middle Ages, the popularity of almond milk can be attributed to religious demands. Much of the medieval Christian diet was restricted by the church, most notably on fish days. Those were days when you weren't allowed to consume meat — or, notably, any product of a warm-blooded animal. The best-known fish days occur during Lent, but many modern Christians continue to observe this tradition at various points throughout the year (incidentally, it's also where Friday fish fries come from, not to mention the McDonald's Filet-O-Fish).

It's pretty easy to see how almond milk would fit into that context. If it's one of those days that you're not allowed to pour cow's milk on your medieval Froot Loops, then a substitute made from Bible-friendly nuts (okay, drupes) would be more than welcome. Then there are the medical benefits. Medieval doctors noted the healing properties of almonds. Specifically, they thought the little nuts were particularly good for the brains of young scholars. So that explains why cookbooks and medical texts going back to the 12th century prominently feature almond milk recipes. But it doesn't explain how the stuff got so popular with the upper crust.

The more you look at recipes from the period, the more you find items like blancmanger, a kind of pudding made with almond milk, stewed chicken, and lots of sugar. Almond milk or no, that's one meal that's not going to fly on Lent. In reality, almond milk probably became a favorite ingredient of the upper classes because it was expensive and exotic. Plus, it takes on coloring quite well, and medieval Gordon Ramsays loved to liven up their meals by mixing in coloring agents like violets, beets, and cornflowers. That all adds up to a must-have ingredient for any fancy 14th-century pantry.

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Curious what else medieval cooks used to whip up? Why not try making one of their specialties in your own kitchen? Maggie Black's "The Medieval Cookbook" is full of recipes from between the fall of the Roman empire to the reign of Henry VIII. If you purchase through that link, Curiosity will receive a portion of the sale.