Seasoning is a process used to protect cast iron and carbon steel cookware from rusting, provide a non-stick surface for cooking, and prevent food from interacting with the iron of the pan. This is a process similar to bluing (steel), forming an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe₂O₃), the black oxide of iron (as opposed to rust, the red oxide of iron (Fe₂O₃). Black oxide provides minimal protection against corrosion, unless also treated with a water-displacing oil to reduce wetting and galvanic action.

Seasoning is a three-step process, involving cleaning the cookware to expose the bare metal, applying a layer of animal fat or vegetable oil, and heating the cookware to bond the fat to the metal. Seasoning also occurs as a natural by-product of using the cookware to cook foods that deposit oils or fats on the pan.

New cast iron that is not pre-seasoned is often sold with a protective coating (wax or shellac). This coating must be removed (typically by scouring) to expose the bare cast iron surface before the pan is seasoned.For already-used pans that are to be re-seasoned, the cleaning process can be more complex, involving rust removal and deep cleaning (with strong soap or lye,or by burning in a campfire or self-cleaning oven^[ to remove existing seasoning and build-up.

Fats and oils typically used for seasoning include lard, hydrogenated cooking oils such as Crisco, and palm or coconut oil (in general, oils that are high in saturated fats, and therefore less likely to become rancid).

Heating the cookware (such as in a hot oven or on a stove top) facilitates a reaction between the oil and the iron, essentially cooking the seasoning into the pan. Some cast iron users advocate heating the pan slightly before applying the fat or oil to ensure that the pan is completely dry and to open "the pores" of the pan.

Newly seasoned cast iron will have a dark brown coating. If the seasoning process is repeated, or after prolonged use, this coating will turn glossy and black, and the non-stick properties of the pan will further improve.

      The cast iron teapot, also knows as a “tetsubin”, is a classic Japanese teapot that dates back to the seventeenth century. These sturdy pots were originally considered to be ordinary kitchen tools, generally used to boil water and brew tea. It wasn’t until the 19th century, when tea drinking became popular in Japan, that having cast iron teapots became a symbol of status in the home. Cast iron teapots have yet to wane in popularity since the seventeenth century because of their beauty and function. These teapots heat evenly, retain heat well and last a lifetime, which make them perfect heirloom pieces. Cast iron teapots are also considered good for your health, since cast iron teaware adds significant traces of iron into each infusion. These teapots are also covered in black enamel to prevent rust from forming inside.