2. Residues

Surface accretion occurs when substances are added to a vessel through use. These include such things as carbon deposits and food residues. An archaeologist can study the deposits and residues left on a vessel to understand how it was used and what was being consumed from it. For example, a vessel that has soot on its exterior base was likely used for cooking since sooting results when carbon is deposited on a vessel as it is used over a fire. The chemical properties of the residues left by foods can also be studied to understand what was actually contained in a vessel. James Skibo (Skibo 1992) has been successful in this regard in differentiating Kalinga rice cooking vessels from those that were used for cooking meat.

a) 77-33-507c

Figure 2.2.14  The interior base of this Tarahumara tesguino pot exhibits residues left by the fermentation process.

b) 77-33-280

Figure 2.2.15  Exterior of Tarahumara tesguino pot showing drip lines from teguino.

c) A-4450

Figure 2.2.16  The carbon deposits on the exterior base of this corrugated vessel from Point of Pines, Arizona suggests that it was used for cooking.

General Considerations

The above discussion has been concerned with understanding ceramic function by using three different methodological approaches: morphology, performance, and use alteration. Although these approaches have generally produced interesting and promising results, especially when used together, a note of caution should be made. First of all, like modern kitchen utensils, most prehistoric ceramic containers did not serve a single function but instead served in a multitude of tasks and chores. Prehistoric ceramic containers were therefore multifunctional. Second, a ceramic container is often used and then reused for something different from its original function. So, for example, a water storage jar may develop a small crack that leaks liquid but not dry goods. Instead of being thrown away, this vessel may be reused for food storage. This also underscores the potential for a vessel to have multiple functions throughout its use-life. Finally, although sherds, or fragments of broken pottery, are useful for some functional studies, such as reconstructing vessel morphology with rim sherds, most research in ceramic function necessitate the use of whole vessels rather than sherds. This is somewhat unfortunate since sherds are encountered in the archaeological record far, far more frequently than whole pots; however, many museums house hundreds, even thousands, of whole vessels that can be accessed for ceramic functional analyses.