Humans need salt to survive. It’s our chief source of both sodium and chloride, essential substances that our bodies cannot produce on their own. Depending on where we live, we sprinkle it on by hand, bake foods inside of it, and drizzle it over dishes in liquid forms like soy or fish sauce. It’s also an indispensable ingredient in food preservation.

By contrast, Piper nigrum, the black pepper that enjoys pride of place alongside salt on most Western tables, is a luxury of subjective value. In the flavor-starved Europe of the middle ages, black pepper—native to south India—commanded obscene prices, to the point that it was sometimes used as a currency in itself. Chefs for noble families heaped it on in proportions we would now find alarming.

Pepper’s scarcity imbued it with a...