 Some of the second earliest examples of steam cooking have been found in Italy and Sardinia, created during the Bronze Age, and in Cochise County, Arizona, where steam pits were used for cooking about 10,000 years ago.In China's Yellow River Valley, early steam cookers made of stoneware have been found dating back as far as 5,000 BCE.From the eighth century CE, thin cypress strips were used to make steamers; today their slatted bases are constructed from bamboo.