In our previous installment on Inca food preservation techniques, we discussed the technique of storing food in buildings known as Collcas – a type of refrigeration employed by the Inca that needed no electricity, but instead relied on low temperatures, drainage, and ventilation to preserve various foods.
However, the Collcas were not the only food preservation method the Incas invented. It was necessary at times to transport large amounts of food, but with most transportation happening on foot, it was just not practical to carry weighty food in large quantities, even with the help of llamas as pack animals. This is how freeze-drying came into play. By removing the moisture from food using cold temperatures and mechanical means of squeezing out liquid, food would be preserved minus their moisture content. This, of course, made it infinitely simpler to carry bundles of tubers and other crops from one place to another within the extensive Inca Empire.
At high-altitude locations in the Andes, it almost invariably freezes at night. The Inca took advantage of this fact by laying out large areas of small potatoes on beds of straw or blankets, and covering them with a cloth. They were then left to freeze overnight. When morning came, the villagers would walk on the cloths, using the weight of their bodies to squeeze the moisture out of the potatoes. The potatoes were then exposed to the sun during the day. These steps were traditionally repeated for several days, resulting in the darker freeze-dried potatoes that you can find, known as chuño. The process is still in effect today, with entire families participating in the stepping and squeezing process.