Stone Boiling

Stone boiling heats water to cooking temperature by dropping heated rocks into a water-filled container, a fuel-intensive process that often requires repeated heating and reheating of stones before the water reaches an effective temperature. Indigenous peoples of the West and Northwest Coast of what is now Canada and the United States used the technique, which allowed more controlled temperatures that made it easier to extract fats and oils and draw more nutrients from them; archaeological evidence from the Northern Plains dates its first use to about 4,800 years ago, with use becoming more prominent between 250 and 1750 CE, a shift the archaeologist Brian Reeves has linked to the need to feed growing populations. The method was also common among Polynesian peoples in precolonial times, including Hawaiians, who used it in part to process natural dyes, as well as Samoans, Tahitians and the Maori, and modern indigenous food sovereignty movements are now reintroducing the technique.