Lipid residues in pottery from the Indus Civilisation in northwest India

An exciting new study that looks at food residues ancient Indus pots found in sites around Rakigarhi to decode the foodstuffs that once were in those pots. By examining the lipids or fatty acids that can be extracted from pots and pottery fragments, investigators were able to determine some of the foodstuffs in the ceramic vessels. This is among the first times such analysis was used in Indus archaeology and adds to the limited research in this field. By looking at pots across rural and more urban locations, during and near the end of Indus civilization, they were also able to establish important correspondences between the nutrition across space and time. Some 73 vessel residues were subject to deep analysis from 7 sites primarily in Haryana, including Rakigarhi, Farmana, Khanak, Lohari Raghi I, Masudpur I and VII and Alamgirpur. These included some of the puzzling perforated vessels found at many Indus sites.

There are suggestions that Harappan food culture may have been more uniform than expected: "However, a broad similarity in products is observed across both rural and urban sites, possibly indicating a degree of regional culinary unity. This similarity has implications for how we understand the dynamics between rural and urban populations in northwest India, where rural populations demonstrate distinctive material culture (Parikh and Petrie, 2019), and also appear to have used different cropping strategies compared to those seen at Harappa, particularly through the growing of millets and rice as opposed to wheat and barley (Petrie and Bates, 2017)" (p. 12).

The results, according to the authors show that "the organic residue analysis of Indus vessels presented here reveal that lipids are preserved in Indus vessels, but lipid concentrations are generally low. Dairy products, ruminant carcass meat, and either non- ruminant adipose fats, plants, or mixtures of these products constituted what was cooking in Indus vessels. The results presented here suggest a similarity in vessel usage across rural and urban settlements, and the multi-functionality of vessels" (p. 13). Ruminant animals are four-stomached creatures like cattle, sheep, goats and buffaloes. Evidence for dairy products is low, with only four vessels showing evidence of such usage. "Comparison with ceramic lipid residues found in prehistoric contexts around the world suggests that the minimal presence of dairy in Indus vessels from northwest India is highly unusual" (p. 9). Perhaps, speculate the authors, "dairy consumption was limited to fewer groups, was not as widely practiced in these Indus settlements, or that dairy products were primarily used in vessels not analysed in this study, or used in vessels made from organic materials that have not survived (e.g. Joshi, 2016). The possibility of dairy being rare or ‘special’ at certain settlements suggests everyone may not have had access to specific animal products" (pp. 9-10).

As far as the perforated vessels go, although there is good evidence from Europe that such vessels were used at the time with dairy products to produce cheese, for example, the authors write, "although the interpretations are presently ambiguous, these results suggest that perforated vessels were not primarily associated with dairy processing (contra Bourgeois and Gouin, 1995). Similarly, it is unlikely these vessels were used as braziers for heating (Mackay, 1938: 207) or simply as colanders for draining or straining liquids (Dales and Kenoyer, 1986: 108–109), as they contain fat-rich lipids" (p. 13). It seems as if the mysterious nature of these objects endures, but chances are, this kind of analysis will one day reveal their true purpose or purposes.

Image 1: Example of contemporary hearth and clay vessel in rural Haryana, India. Image credit: Akshyeta Suryanarayan. Image 2: Lipid residues in pottery from the Indus Civilisation in northwest India.