Salt is like no other substance we eat. Sodium chloride is a simple, inorganic mineral: it comes not from plants or animals or microbes, but from the oceans, and ultimately from the rocks that erode into them. It’s an essential nutrient, a chemical that our bodies can’t do without. It’s the only natural source of one of our handful of basic tastes, and we therefore add it to most of our foods to fill out their flavor. Salt is also a taste enhancer and taste modifier: it strengthens the impression of aromas that accompany it, and it suppresses the sensation of bitterness. It’s one of the very few ingredients that we keep in pure form at the table, to be added to individual taste as we eat.