Cacao Residues in Ancient Maya Vessels from Rio Azul, Guatemala

Introduction

• The study focuses on chemical analyses of residues from ceramic vessels in an Early Classic Maya tomb in Rio Azul, Guatemala.

• The residues contained theobromine and caffeine, indicating the presence of cacao.

• Significance:

  • Demonstrates a method for recognizing ancient cacao use.

  • Verifies glyph interpretations.

  • Provides data on the contents of Maya vessels for functional interpretations.

Background

• Historic literature attests to the use of cacao beans by the Maya as currency and in beverages at the time of the Spanish Conquest (Tozzer 1941).

• Prehistoric Maya cacao use is evidenced by:

  • Whole cacao beans (Kidder 1947:71).

  • Cacao wood fragments (Hammond and Miksicek 1981:260-269; Miksicek 1983:94-104; Turner and Miksicek 1984:179-193).

  • Clay models of cacao beans/pods on ceramic vessels (Morley et al. 1983:210).

• These findings date to the Late Preclassic and Classic periods.

Research Focus

• Ball (1983:136) suggested investigating lidded tripod cylinders as specialized commodity containers, possibly for cacao.

• The research identifies cacao chemically in ceramic vessels, one with hieroglyphs signifying cacao content.

Methodology

• Dry residues were collected from the interiors of four ceramic vessels from a tomb at Rio Azul.

• The tomb is located beneath structure C1, an Early Classic monument (Adams 1986:420-451).

• Tomb 19 was discovered in 1984 during a five-year research effort.

• The tomb was constructed by cutting a shaft and chamber into marl bedrock.

• The tomb was carefully sealed, preserving organic materials (Hall 1986:69-110, 1989).

Tomb Contents and Context

• Wooden planks and a kapok pad/mattress were placed in the burial chamber.

• A corpse on a wooden litter was placed on the pad.

• Textiles, possibly clothing or a shroud, were found around the skeleton.

• Grave goods included 14 pottery vessels, including vessel 15 with a "child-proof" lid (Hall 1986).

• The vessels likely contained food and beverages for the afterlife.

Dating and Ceramic Assemblage

• Tomb 19 is tentatively dated to A.D. 460-480 (Early Classic period).

• The ceramic assemblage includes:

  • Six cylindrical pots with lids and tripod feet.

  • A globular jar.

  • Six shallow-basin plates.

  • A circular pedestal or ring stand.

  • A stirrup-handled pot with a bayonet-type locking mechanism (vessel 15).

• Cylindrical pots belong to the Balanza Black ceramic group.

• The stirrup-handled pot is similar to the Aguila Orange ceramic type.

Residue Analysis and Observations

• Most ceramic vessels retained visible organic matter on their interiors.

• Residues were encrusted on vessel walls and found as powders on vessel bottoms.

• Residue lines indicated the original liquid levels in the vessels.

Hieroglyphic Text on Vessel 15

• Vessel 15 has a hieroglyphic text of 15 glyph blocks (Stuart 1986:117-121).

• The text is believed to name the vessel owner and type (Stuart 1988:153-157).

• Two glyphs on vessel 15 spell ca-ca-wa, rendered as "cacao" or "cocoa" (Figure 2A, D).

• The position of the cacao glyphs suggests the vessel was meant to contain cacao.

• The phrase "for… cacao" appears on vessel 15 and is accompanied by undeciphered hieroglyphs that may describe the type of cacao or a recipe.

Chemical Testing

• Chemical testing was prompted by cacao hieroglyphs and liquid marks on cylindrical pots.

• Research was conducted at the Hershey Foods Corporation Technical Center.

• Cocoa is the only known Mesoamerican commodity containing both theobromine and caffeine.

• Samples from five vessels were extracted with water and filtered prior to analysis.

• High-pressure liquid chromatography (HPLC) studies were conducted.

Analytical Procedures

• Initial studies with ultraviolet (UV) detection indicated peaks at the retention time of theobromine and caffeine.

• Photo-diode-array (PDA) detection system was used to obtain UV spectra at different points on the peaks.

• First and second derivative spectra were found to give complete agreement for these peaks.

• Liquid-chromatography/mass-spectrometry studies confirmed the existence of the compounds.

• Data showed complete agreement between standard compound data and data obtained from the vessel 15 extract.

Results

• Vessel 15 contained cacao, based on the detection of theobromine and caffeine.

• Two of the four tripod cylinder vases had definite indications for theobromine only.

• A third had weak indications for theobromine only.

• The fourth showed no indications for theobromine or caffeine.

• Three vessels (vessel 15 and two tripod cylinder vases) definitely held cacao in some form, and a fourth likely did as well.

• The fifth vessel produced no sign of cacao.

Conclusion

• The methods described can identify the presence of ancient cacao under certain conditions.

• Many Maya vessels of the type represented by the Rio Azul specimens were likely used as containers for cacao drinks.

• Analysis of physical matter remaining in excavated Maya vessels should be compared with hieroglyphs on the vessels.

• Covariant patterns can aid in future decipherments of hieroglyphs.

• Efforts are underway to identify other food components of the tomb 19 vessel scrapings.

• Further progress will permit additional discoveries in Maya epigraphy and archaeology.

• This effort illustrates the advantages of interdisciplinary research through cooperation of archaeologists, analytical chemists, and epigraphers.

The study examines residues from ceramic vessels in an Early Classic Maya tomb in Rio Azul, Guatemala, revealing the presence of cacao through the detection of theobromine and caffeine. Historic literature indicates that cacao was used by the Maya as currency and in beverages. The research methodology involved collecting and analyzing dry residues from four ceramic vessels found in a carefully sealed tomb, which also contained burial goods. Tomb 19 is tentatively dated A.D. 460-480, comprising a variety of ceramic types that likely held food and beverages for the afterlife.

Chemical analysis confirmed cacao in vessel 15, indicated by specific compounds. Results showed that three of the vessels contained cacao, suggesting that Maya vessels were commonly used as containers for cacao drinks. The study highlights the significance of interdisciplinary research in advancing the understanding of Maya culture and its practices surrounding cacao consumption.