Both hard and soft maple syrups as well as walnut and hickory syrups were prepared annually in late winter when the tree sap began to run. Native Americans tapped the trees, collected sap, and then boiled the sap down into a mildly concentrated syrup. The boiling pots were of clay, animal skins, or sealed bark, and the cooking often was accomplished by the hot stone method. The resulting syrup was stored in bark containers that were sealed and waterproofed with pitch. It is unlikely that a full yearβs supply was produced, considering the precontact technology. Northern tribes often used the occasion of syrup-making to socialize and probably consumed a fair amount of the product on site. After contact, Native Americans took advantage of iron pots and European familiarity with cane sugar production to crystalize syrup into sugar, making transportation and storage far simpler and production higher.