A UK judge has decided that Pringles aren’t potato chips, which could save Procter & Gamble millions in taxes every year. The judge based his decision in part on the fact that the chip-like snack is only 42 percent potato. The UK doesn’t apply sales tax to most foods, but potato chips and other snack-like products are taxed.

Pringles were invented more than forty years ago by Alexander Liepa, a food scientist at Cincinnati-based P&G. Liepa received a patent (3396036) on August 6, 1968 for a “potato food product” made from a dough consisting of 21-46 percent potato solids, 1-15 percent milk solids and 53-73 percent water. He later patented additional improvements to the formula (3998975) and the design of a machine for molding the dough into the product’s trademark concave shape (3608474). (Also see trademark application 75207172.)

Happy 40th birthday, Pringles!