He used that money to rent a horse and wagon. Every morning he bought cheese at the wholesale market and drove it around Chicago, selling it to neighborhood grocers. It was slow, unglamorous work, and for the first several years it barely paid. What he learned in those years, though, was the one thing nobody at the wholesale market ever had to face: what happened to the cheese after it was sold.

It spoiled. Grocers bought big wheels of cheese, cut them to order, and watched the rest dry out, crack or go moldy before they could sell it, especially in the summer. Every wheel carried a hidden loss that the grocer absorbed and the wholesaler never saw. Kraft saw it every day, because he was standing in the store when the grocer complained.

So he stopped thinking of himself as someone who sold cheese and started working on the grocer’s real problem. He brought his brothers into the business, opened a small plant in Stockton, Illinois, in 1914, and spent years experimenting with ways to make cheese last. In 1916 he patented a process for pasteurizing cheese so it resisted spoiling and could be shipped long distances in tins. Traditional cheesemakers looked down on it. The grocers didn’t care, because it didn’t go bad on their shelves. Then the U.S. government bought millions of pounds of it to feed soldiers during World War I, because it was one of the few cheeses that could survive the trip.

By 1930, Kraft’s company made roughly 40 percent of the cheese eaten in the United States. The product that built it wasn’t a better cheese in any sense a cheesemaker would recognize. It was cheese that solved the storekeeper’s problem.