St. Clair sits on an ocean of salt

Far below St. Clair’s pretty riverfront lies the leftover of an ancient sea — a bed of salt and salty brine that turned a small Michigan river town into a name in kitchens nationwide. People kept drilling for it and kept losing money: the first wells in the 1860s never paid. Then in 1884 the Thompson Brothers drilled past 1,600 feet, ran a clever two-pipe system that pumped fresh water down to dissolve the salt and drew the brine back up, and finally turned a profit.

The brand came two years later. In 1886 an inventor named John Alberger showed St. Clair businessmen a process that used pressure rather than a vacuum to crystallize the brine, growing salt grains with odd, many-sided faces that clung to food and dissolved fast. Charles F. Moore and Mark Hopkins bought the patent, set up a works on the river, and renamed the company Diamond Crystal Salt to brag on the purity. The name stuck for more than a hundred years.

For generations Diamond Crystal was simply what St. Clair did. The plant drew its own brine from beneath the town, boiled and pressed it into the salt that went out in boxes and bags to households and food companies across the country. The company changed hands more than once — General Foods owned it for a stretch — and eventually Cargill took over the works, which kept making salt by the river long after the founders were gone.

It’s an easy thing to forget while you stroll the boardwalk: the calm blue St. Clair River up top, and a buried ocean of brine down below that quietly built half the town’s payrolls. The shaker on your table may not say it anymore, but for a century a fair amount of America’s salt came up out of the ground right here.