In the highest altitudes of the Andes, freezing temperatures are pretty much guaranteed at night. The Incas used this to their advantage by bringing potatoes to these chilly environments and letting them freeze beneath a cloth. The residents of the wintry villages would then walk on the cloths in the morning to squeeze out the moisture from the potatoes. The repeated process would result in freeze-dried potatoes known as chuño.
This product had several distinct advantages in the Incan empire, as it does today. First, it was lightweight. This allowed soldiers to carry large quantities of it with them on their campaigns with relatively little effort. Second, chuño, like all freeze-dried food, is extremely durable and can keep for years without being refrigerated. This made an excellent backup food source in case of drought, natural disaster or any other type of crop failure. Even today, in the case of crop failure, Andean highland natives will rely upon chuño to get through the difficult times. Lastly, the freeze-drying process would eliminate the bitter taste from some species of potatoes, making them much more palatable.