Containers: Cooking Containers: Cast Iron

The second ferrous metal in common use is cast iron, or pig iron. It is composed of iron with 2 percent to 4 percent carbon added. As the name implies, this metal is usually worked by casting, either ladled out of the furnace or run from the furnace mouth directly into sand molds. This was the cheapest metal available in the eighteenth century because it is the first stage in smelting iron. Its low cost made it appealing in spite of its greatest drawback—extreme brittleness. But this lack of malleability makes cast iron resistant to warping, and it withstands high heat extremely well. However, cast-iron pots are actually fragile and can break if dropped on a hearth. Sudden thermal shock, or expansion of contents during freezing, can also cause breakage. Once broken, cast iron is very difficult to fix. Cast iron is the slowest heat conductor of all the common metals. This can be problematic except when heating thin liquids or frying. The pieces commonly made from cast iron are pots, griddles, firebacks, stoveplates, Dutch ovens, teapots, and occasionally andirons.