Quotes

Soup is a primarily liquid food, generally served warm

Evidence of the existence of soup can be found as far back as about 20,000 BC. Boiling was not a common cooking technique until the invention of waterproof containers (which probably came in the form of clay vessels). Animal hides and watertight baskets of bark or reeds were used before this. To boil the water hot rocks were used. This method was also used to cook acorns and other plants.