Ancient Home Chefs

Home chefs often use a pestle and mortar and a cutting board to prepare meals. So, too, did ancient cooks.  

“People have lived here for time immemorial and have been processing native plants on ground stone tools for a long time, too,” said archeobotanist Stefania Wilks, author of a new study on Native Americans’ cooking habits, referring to the western United States.  

The researchers identified manos and metates as the ancient equivalents of today’s common kitchen tools and explained how they were used. 

A metate is a large, flat stone or a rocky indentation, while a mano is a handheld stone tool used to crush plant and animal matter against the metate, explained Cosmos Magazine.  

Open-air metates carved into bedrock are relatively easy to spot at archeological sites and can be more than 15,000 years old. Metates tend to be found in groups or in rows. 

To understand the use of these tools by Native Americans, archeologists used new microscopic techniques and focused on bedrock metates in Warner Valley, Oregon. 

Researchers had believed bedrock metates might still contain an untapped source of starch granules from when ancient populations refined plant matter, as the small crevices in the stone likely shielded the granules from degrading. 

They used water and an electric toothbrush to scrub the metate and then added a deflocculant, which acts like laundry detergent, to break up clumped particles and free them from the stone’s crevices. They did the same on nearby rocks not used as metates to serve as the control group. 

“It increased our confidence that what we were seeing was direct evidence that different plant species with starchy organs were processed on the metate,” said Wilks. 

The team then analyzed the samples under the microscope and confirmed that the matter retrieved from the crevices of the metates consisted of starch granules.  

They then compared the shape and features of the starch granules in the sample with those of plants in the area and found that among the plants processed on the metates were biscuit root, part of the carrot family, wild grasses, likely wild rye, and plants from the lily family – still important food sources for local Indigenous people today.