Thursday, January 17, 2019

Grinding Stones

Angela Huster

Stone tools for grinding corn – manos and metates – are a fundamental hallmark of Mesoamerican culture. Prior to the introduction of modern electric mills, Mexican women would spend several hours every day grinding corn with a mano and metate. A mano and metate were traditional wedding gifts, because they were so fundamental to setting up your own household. At Calixtlahuaca, they are one more line of evidence for how the site is subtly different from many contemporaneous Aztec sites. 

A woman instructing her daughter how to grind corn in Codex Mendoza

In Central Mexico, grinding stones go through two major changes. First, early in Mesoamerican prehistory, there is a change from mostly basin metates (with walls around the edges) and smaller handstones, to mostly flat metates with longer handstones. Archaeologists generally assume that this change is related to a shift toward grinding pre-soaked corn (a soft food that doesn’t bounce around when it’s being ground), rather than small, hard seeds or dry corn. In the US Southwest, the introduction of corn produces the opposite pattern in metate forms, because people there grind their corn dry (Adams 1999). There is a second change in grinding stone tools in the Postclassic, when metates with legs and thin manos with handles on the ends become more common. These changes would have made fine-grinding corn more efficient, perhaps as a way to reduce the fuel needed for cooking or to make it easier to digest (Biskowski 2000)

Mano fragments from Calixtlahuaca

At Calixtlahuaca, this second change didn’t really happen. We get some metates with legs, but they aren’t the only type in use. More noticeably, the shift from “Classic style” relatively thick manos without distinct handle grips on the ends, to thinner “Aztec style” manos with handle grips is missing. When I classified the ground stone from the site, I planned on using the same coding categories from Mike’s previous projects in Morelos. This classification basically has five categories for manos, ranging from one for a thick mano without differentiated handles, to five for a thin mano with pronounced handles. At sites in Morelos, most manos are 4s or 5s on this scale. At Calixtlahuaca, there were only a couple of cases that even scored as 3s; most were 1s or 2s.

Ways of classifying the shapes of manos
This “conservatism” in grinding technology fits into two larger patterns at Calixtlahuaca. First, it is likely related to differences in how maize was eaten in the Toluca Valley, relative to many other parts of Central Mexico (see previous posts on maize cooking HERE). If people at Calixtlahuaca didn’t eat as many tortillas (which require finer-than-average grinding), they may not have needed the increased efficiency provided by handled manos. Second, the continued use of an older style of grinding stones is part of a broader set of traits that people in the Toluca Valley maintained long after their neighbors in the Basin of Mexico, including the use of red-on-natural pottery, particular styles of censers, and lots of obsidian from the Ucareo source.

Works Cited:
Adams, Jenny L.
                1999       Refocusing the Role of Food-Grinding Tools as Correlates for Subsistence Strategies in the U.S. Southwest. American Antiquity 64(3):475-498.

Biskowski, Martin
                2000       Maize Preparation and the Aztec Subsistence Economy. Ancient Mesoamerica 11:293-306.