If an army travels on its stomach, Charles Sanna helped win the Korean War. He developed a way to produce millions of individual packets of powdered coffee creamer for American troops.

Military contracts stipulated, though, that his family’s company, Sanna Dairy Engineers, would be penalized if the orders were underfilled. So, to be safe, the company produced extra packets. But that meant that it was routinely stuck with excess supply, since the Army had also insisted that none of the overstock be used to fill future orders.

The surplus powder was savory, potentially valuable and perishable. With necessity being the mother’s milk of invention, Mr. Sanna had another idea.

“I believed that it would make an excellent ingredient for a hot cup of cocoa,” he recalled.

He experimented over the stove in the family kitchen in Menomonie, Wis., and enlisted his five children and students from a local elementary school as guinea pigs for countless taste tests.