My kids came home from their grandparents’ house carrying two things I never expected to see paired together: a packet of salted peanuts and a bottle of Coca-Cola. Before I could put them away, they stopped me and explained that Grandpa had shown them the “right” way to enjoy them. According to him, you’re supposed to take a few sips of Coke, pour the peanuts directly into the bottle, and then drink and eat them together.

At first, I genuinely thought they were joking. Peanuts floating around inside soda sounded like something children would invent on a dare. But they were completely serious. They told me Grandpa had done exactly the same thing, casually dropping a handful into his Coke before drinking it. When I asked why anyone would do that, they simply shrugged and said, “Grandpa says everybody used to do it.”

That was when I finally asked their grandparents for an explanation. It turned out there was nothing strange about it to them. They explained that peanuts in Coca-Cola were an old Southern tradition they had grown up with. The salted peanuts soften slightly while still keeping some crunch, and the combination creates an unusual mixture of salty, sweet and fizzy flavors. The practice really does have roots in the American South and is commonly associated with generations of working families.

Grandpa explained that the tradition was also practical. One popular explanation traces it back to workers and farmers around the 1920s. Instead of grabbing peanuts with dirty hands while working, they could pour the shelled peanuts straight into a bottle of Coke and consume their snack and drink together. It required only one hand and eventually became something people continued doing simply because they enjoyed the combination.

So the grandparents hadn’t taught my kids some bizarre new food experiment at all. They had simply passed down a little tradition from another generation. I eventually tried it myself—salted peanuts dropped straight into an ice-cold Coke—and suddenly understood why it had survived for so long. It was sweet, salty, crunchy and strangely satisfying. The thing I thought made absolutely no sense turned out to be an old-fashioned Southern snack hiding in plain sight.