Equipment consistent with alkaline maize processing has been found on Guatemala's southern coast dating as early as 1200 to 1500 BCE, but the earliest DIRECT chemical confirmation, maize starch residue actually showing the alkaline treatment, has so far only been recovered from the Late Classic period, roughly 770 to 895 CE, at San Bartolo, Guatemala. The gap between equipment and confirmed residue leaves centuries of practice unproven either way.
What would resolve this Starch-residue or isotopic analysis on cooking equipment from the Preclassic and Early Classic periods, closing the gap between the 1200 to 1500 BCE equipment horizon and the 770 to 895 CE residue-confirmed horizon.
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