The efficiency of Australian grindstones for processing seed: A quantitative experiment using reproduction implements and controlling for morphometric variation and grinding techniques

This paper presents a controlled experimental examination of the efficiency of Australian Aboriginal grindstones with a variety of surface morphologies in milling seeds into meal. Several replicate sandstone grindstones (large and small millstones with functional surfaces ranging in length from 43 cm to 16 cm and a mortar) were employed to process three domesticated commercial grains that serve as viable proxies for native grains. These were processed in 10 min grinding sessions. Our results show that large millstones significantly outperform both the small millstones and the small mortar in the net output of ground grain. We also find that other factors may influence productivity, including the amount of wear and the seed being processed. These variations are of sufficient magnitude to have possibly influenced crucial economic decisions.