Poutine is Canada's most famous culinary export, consisting of french fries topped with fresh cheese curds and brown gravy. It originated in rural Quebec in the 1950s. The word 'poutine' is Quebecois slang for a 'mess.' The key to authentic poutine is the 'squeak' of the cheese curds. This squeak is caused by long strands of protein (casein) that haven't yet been broken down by age or acidity; as they rub against the enamel of the teeth, they create a high-pitched vibration. If the curds are refrigerated, they lose their squeak and their ability to resist melting under the hot gravy.