Before the development of fired pottery, cooking was limited to either cooking food directly on an open hearth or several methods of indirectly heating food. Roasting over an open flame works well for firmer foods such as red meats but is not as desirable for more delicate foods such as fish or fibrous foods that require a longer, slower cooking time.
One method of cooking was boiling using hot rocks to heat the water. Water was placed in a tightly-woven basket or a container made of skin. These containers would burn if placed directly over the fire; thus, smooth, rounded river cobbles were heated in the coals and then dropped into the water. The water would heat up and cook the food. The sudden change in temperature from the hot coals to the cold water would frequently cause the rocks to crack and split. Finding this "fire-cracked rock" is a sign to archaeologists that cooking activity took place at a site.
The Poverty Point Culture (1730-1350 B.C.) developed a sophisticated earth oven technology. This culture lived in the Mississippi Delta area in parts of what is now Louisiana, Mississippi, and Arkansas. In much of this area, rocks are not available. The Poverty Point people made an oven by digging a hole in the ground. They then packed heated clay balls around the food, and covered the pit. These clay balls, or "poverty point objects" as they are called, come in many different shapes. The objects fall into five broad categories: melon-shaped, cylindrical, cross-grooved (with an indentation around the middle), biconical (somewhat diamond-shaped), and spheroidal. There are many, many variants of these basic types. Some are just clay balls that have been squeezed, with adults' or children's fingerprints still visible on them. Some are plain, while others are ornately decorated. One has even been found with a human face on it. Experiments have shown that the different shaped objects had different heating properties. Varying the objects used may have been the Poverty Point cook's way of regulating cooking temperature.
The later development of pottery allowed placing a vessel directly into contact with fire or coals and increased the range of available cooking methods.
(References: Gibson, John L. 1996. Poverty Point: A Terminal Archaic Culture of the Lower Mississippi Valley, 2nd ed. Baton Rouge: Louisiana Archaeological Survey and Antiquities Commission.
Neuman, Robert W. 1990. An Introduction to Louisiana Archaeology. Baton Rouge: Louisiana State University Press.
