A newly developed compound-specific stable carbon isotope technique allows the detection of maize in absorbed organic pottery residues. This method was applied to absorbed organic residues from a variety of Mississippi Valley potsherds, and successfully identified maize components. Maize was cooked in sampled vessels less often than expected, but otherwise fitted expected patterns of maize use derived from stable carbon isotope analysis of human bone from the region. Absorbed organic pottery residue analysis is useful in determining pottery use, particularly in concert with other analytical methods.

This paper assesses the fate of lipids associated with low-temperature and pit-fired pottery to determine to what degree organic compounds persist or are removed during short-firing episodes below 800°C. Three different types of clay were fired using contrasting techniques including at 400°C for 4 h in a muffle furnace, and pit-firing in which pottery was fired to higher temperatures but for shorter periods of time. Total lipid extracts obtained by solvent extraction of test sherds were screened using gas chromatography-flame ionization detection (GC-FID) to determine the lipid concentrations and gas chromatography-mass spectrometry (GC-MS) to identify the organic compounds present. The results showed that firing of clay removes all naturally occurring alkyl lipids; however, during pit-firing, diterpenoid lipids were introduced into the clay as a condensate from pine ( Pinus spp.) wood used as fuel. These results confirm that alkyl lipids, e.g., fatty acids, can be reliably associated with the use of vessels, although caution is required when interpreting the origins of lipids that might derive from fuel used in firing. bs_bs_banner 0.5 cm in measurement, and were dried thoroughly at room temperature before firing.The clay tiles were fired using two methods: in a muffle furnace at 400°C for 4 h (firing 1) and in several firing patterns in earthen pits excavated in the ground (firings 2-4). The pit-firing temperatures were measured with a Bailey Type K Chromel-Alumel Analog pyrometer (accuracy 132 E. A. Reber et al.

Discovering what was cooked in a pot by identifying lipids trapped in the potsherds has been a highly successful method developed in recent years. Here the authors identify a compound which shows the pots had been used to process maize – probably the most important foodstuff in later prehistoric North America. The uptake of maize is confirmed as coincident with the Mississippian fluorescence.

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