Cooking in clay vessels has a long history, stretching back to at least the ancient Roman times, and is still a favored way to cook today. The covered clay dish creates an environment allowing the heat and moisture to circulate, resulting in an evenly cooked dish that is tender and juicy.
The traditional clay pot is one that is not glazed and has a deep base along with a deep lid. There are also some specific varieties, including the Spanish cazuela, a round, glazed earthenware cooking vessel, as well as the tagine, the Moroccan cone-topped clay pot. These clay cookers can be glazed, partially glazed, or unglazed. Depending on whether it has a glaze or not will determine how it should be cared for and cleaned.
The advantage of a glaze is that it is easier to use and clean and it doesn't need seasoning. You will lose some of the benefits the clay pot offers–the ability to absorb water and circulate steam, which makes the meat moist and tender as well as bread soft on the inside with a crispy crust. The unglazed clay is also alkaline, balancing the pH in the food, adding a little sweetness to acidic ingredients, such as tomatoes.
Seasoning Your Clay Pot
If your clay pot is unglazed, you need to soak and season it. Soaking the clay pot in water for at least 15 minutes and up to two hours will bring moisture to the porous inner surface, allowing the food to steam while cooking so the food doesn't dry out. Seasoning the pot will strengthen the surface and prevent cracking, making it more durable for long time use.
After the pot is soaked in water, it should be dried, the interior unglazed surfaces rubbed with a clove of garlic and then the inside coated with vegetable or olive oil. Then it should be filled 3/4 of the way full with water and heated at a low temperature either on the stovetop or in the oven for two to three hours.
Using Your Clay Pot
Before each time you plan to cook with the clay pot, you need to soak it in water (only if it is unglazed). Submerge in cold water–both the base and the lid–for 15 minutes. The water will penetrate the porous surface and assist in the steaming process during cooking. Simply pat dry and fill with your recipe's ingredients.
Clay pots are sensitive to temperature change and will easily crack so it is important that you don't expose the cooker to extreme temperature differences. Never put the clay pot in a preheated oven–it should always go into a cold oven so it is in an environment where the temperature gradually increases. If cooking on the stovetop, you need to raise the heat of the burner slowly (using a diffuser is helpful).
There are different clay pots designed to be used in different ways, so be sure to read your clay cooker's instructions before using. Some are made for the stovetop and can handle higher, more direct heat while others are for the oven only.
Cleaning Your Clay Pot
Since the clay is porous, it is important to follow certain steps when cleaning the pot. Do not use soap or detergent to clean as the soap will soak into the pores of the clay and then leach into your food the next time you use it. Instead, use scalding hot water and a stiff brush to clean the pot. Baking soda or salt may be used as a cleanser with a scrub sponge.
For stubborn stains, use a very coarse unsoaped stainless steel pad, or let the cooker soak overnight filled with water and one to four tablespoons of baking soda. A baking soda soak will also help remove odors and freshen the cooker after cooking pungent foods.
Storing Your Clay Pot
Store your clay pot with the lid inverted, nestled inside the bottom with a paper towel in between so it can breathe. Make sure it is completely dry before you put it away. During periods of long storage, mold may form. To remove any mold, apply a paste of equal parts of baking soda and water. Leave it on at least 30 minutes, then brush, rinse well, and let it thoroughly dry, preferably in bright sunlight.