Why was pepper once as precious as a pig, and did it really hide rotten meat?

In the Middle Ages pepper was precious because it was expensive, not because anyone needed it to hide bad meat. In 15th-century Oxford a whole pig cost about the same as a pound of the cheapest spice, and that spice was pepper. Nobody pays a pig's price for something meant to disguise spoiled food.

That popular idea, that medieval cooks used spices to preserve food or to mask the taste of rotten meat, is false. Spices are rather ineffective as preservatives compared with salting, smoking, pickling or drying, and they are ineffective at covering the taste of spoiled meat. Pepper is relatively ineffective even where some spices show antimicrobial properties in the lab, and far cheaper salt is more effective.

Pepper was valued because it was a luxury with a long journey behind it. Black pepper is native to South Asia and has been known to Indian cooking since at least 2000 BCE. The ancient port of Muziris, on India's Malabar coast, was famous for exporting it, and its trade reached the Roman Empire, Egypt, Mesopotamia, the Levant and Yemen. In Rome pepper was a well-known if expensive seasoning, and a third-century cookbook uses it in a majority of its recipes.

Prices later fell as more pepper reached Europe, and it turned from an item exclusively for the rich into an everyday seasoning for people of more average means. Today it makes up one-fifth of the world's spice trade.