Peanuts are a little more popular in the minor leagues, where about 8 percent of the 40 million spectators each season buy a bag. In the majors, it’s closer to 6 percent, Mr. Nolan said.

Peanuts began flirting with baseball in the 1890s, after Harry Stevens, an immigrant from Britain, moved to Ohio and fell in love with the game. He designed and sold its first scorecards.