Pemmican production consists of pounding strips of meat into a pulp or powder, adding lard and fruit as binders, then drying it to make hard cakes. As for refrigeration, some cultures used to divert meltwater streams near their homes and settlements, then store food in the cold water. Colonial settlers dug root cellars, which they packed with winter ice insulated with straw. The process is called oxidation, a chemical act or process in which electrons are removed from a substance. In the case of the nail, its iron content combines with oxygen in the water to form rust.
Oxidation occurs widely in nature.
It occurs inside your body when food molecules combine with inhaled oxygen to slowly produce carbon dioxide, water and energy. The next day, fill a similar jar with fresh tap water. Drop identical iron nails into each jar and wait a few more days. The nail in the boiled water won't be as rusty because there's less oxygen in the water. Please include your name, city of residence and phone number.