Jane Says: Cooking in Clay Makes the Ultimate Slow Food
“What’s the point of cooking food in a clay pot?”
A clay pot is the ultimate slow cooker: It heats up gradually, diffuses heat gently and evenly, and retains heat beautifully. Food cooked in a clay pot stays moist and hot, so you will generally use less liquid and/or fat. As Paula Wolfert writes in the masterful Mediterranean Clay Pot Cooking, it coddles food.
And it is older than history itself. In 2012, a team of Chinese and American archaeologists used radiocarbon dating to confirm that pottery fragments found in a cave in southeast China were made between 19,000 and 20,000 years ago, during the Last Glacial Maximum (aka Ice Age to you and me). “That is thousands of years before people began farming some 12,000 years ago, suggesting that the pots were made by hunter-gatherers, which is contrary to previous thinking,” reads an account in New Scientist. The scorch marks and traces of soot on the outer surfaces indicate that the pots may have been used for cooking.
Generally speaking, the term pottery refers to all types of vessels molded from clay, then dried and fired (that is, baked, usually in a kiln) to harden and set their shape as well as increase their strength and durability. Clay pots for cooking can be made of earthenware, stoneware, or flameware.
Sometimes called terra-cotta, earthenware is low-fired (1,800 to 2,000 degrees Fahrenheit), and thus remains able to expand and contract slightly. It comes unglazed, glazed, or partially glazed. Many people think that glazing negates the unique properties of clay, but that’s incorrect. The other day I spoke with Ashrf Almasri, who, with his wife, Shelly, owns the clay pot citadel Bram, in Sonoma, to get the scoop. “Glazed clay pots have crazing—small cracks that develop as the glaze and clay expand and contract at different rates during the firing,” he explained. “So moisture and cooking flavors enter the clay through the cracks. It still breathes.”
Unglazed earthenware pots are renowned for their ability to impart goût de terroir, a “taste of the earth.” That’s certainly true the first time or two you use a new pot, but after that the earthy flavor subsides. That’s because “the pot glazes itself,” said Almasri, a native of Alexandria, Egypt, who has eaten from clay pots his entire life. “The cooking oils and so on keep seasoning the pot.”
Many earthenware pots can take direct heat, although a heat diffuser (an inexpensive thin metal plate you set between pot and burner) must be used with electric or glass-ceramic stovetops. If you’re new to clay pot cooking or are putting a new pot through its paces, it’s a smart idea to use one on a gas burner as well. For information on the seasoning and care of earthenware pots that’s in-depth yet not intimidating, visit Bram’s “Clay Cooking 101” page.
Made from a mixture of clay and fusible silica and first produced in Shang Dynasty China (circa 1600–1046 BCE), stoneware is fired at a higher temperature, which causes it to become vitrified—it fuses together and becomes harder, denser, and glass-like in texture and appearance. Usually glazed, it’s not used on top of the stove but rather in the oven.
The common name for high-fired stoneware that’s flameproof, flameware can be used on the stovetop as well as in the oven. According to a nifty little history from Whidbey Island–based Cook on Clay in Washington state, it has its roots in the early 20th century but came into its own during the ’50s and ’60s, with clays specifically developed to withstand temperature extremes by ceramic artists such as Mikhail Zakin, Karen Karnes, and Bill Sax. Flameware “is very durable and user friendly,” wrote Shelly Larson Almasri in an email. “It is very tough and thermal shock resistant, and it is very difficult to crack.”
A list of clay pots available to home cooks today reads like a world tour and includes the Moroccan tagine, Egyptian bram (from which the Almasris’ store gets its name), Turkish guvec, Spanish cazuela and olla, French poêlon and daubière, Italian mattone and umidiera, German Romertopf, Chinese sand pot, and Apache mica bean pot. Each shape has its own sensuous allure, and when faced with a large selection, it can be difficult to choose. It depends in large part on what you like to cook and for how many, of course, as well as your kitchen storage situation and the health of your bank balance.
Below are a few options that get major points for versatility—you can cook all sorts of dishes in them, they can be used on the stovetop or in the oven, and they make great serving pieces too. For stovetop cooking, remember to pick up a heat diffuser, available at kitchenware shops and any number of online sources. And when transferring a clay pot from stovetop or oven to kitchen counter, use good pot holders and always put the pot on a thick folded kitchen towel or wooden board; a cold surface such as granite may cause it to crack.
This round, straight-sided, relatively shallow earthenware pot is glazed everywhere except on the bottom and comes in various sizes; one with a lid is especially handy. Some years ago, I bought an 11-inch cazuela so I could easily make tapas-style sizzling garlicky shrimp at home, but it quickly became indispensable for gratins, baked pastas, roasted Pacific halibut steaks, chicken thighs dusted with smoky Spanish paprika, and more. In Mediterranean Clay Pot Cooking, Wolfert specifies Spanish cazuelas, as they’re “well made, stronger than most others, and totally lead free.” Two excellent suppliers are La Tienda and The Spanish Table.
Chinese Sand Pot
If you’re on a tight budget, it’s hard to beat a sand pot, which comes in various sizes, starting at around $10. The squat-bellied, lidded earthenware casserole with a glazed interior has a sand-textured unglazed exterior bound with a protective wire cage and can be used in the oven or on the stovetop. A sand pot is traditionally used for “red-cooked” dishes and other stews, but don’t stop there: Wolfert uses it for any number of soups, stews, beans, or rice dishes, and the waterless cooking of vegetables such as potatoes, carrots, turnips, and beets (they steam in their own natural moisture). Sand pots are available at Asian department stores or markets and by mail order from the Wok Shop in San Francisco and other online sources. Follow the manufacturer’s instructions for seasoning, but depending on where you buy the pot, there may not be any. In that case, do as Wolfert does: Soak it in water for 24 hours before the first use; after that, each time you use it in the oven, soak it in water for five minutes beforehand.
A deep, heavy, roomy casserole is ideal for slow-simmered soups, stews, and bean dishes. One of the most beautiful, well-crafted earthenware ones I’ve seen is the Etruria Classica carried by Rhode Island chef Walter Potenza, who’s credited with popularizing clay pot cooking in American restaurant kitchens. And La Chamba casseroles, made of black micaceous clay (mica is a natural insulator) and imported from Colombia, are superb as well; they’re available from Bram, Toque Blanche, and other online sources. When it comes to flameware, check out the handmade Dutch oven made by Clay Coyote in Minnesota, or the various Dutch ovens/stewpots from Emile Henry (available at kitchenware stores and online).
You can cook beans in a casserole, true, but if you cook lots of them, you may decide to invest in a dedicated bean pot (it will also handle soups and stews). Bram has a terrific assortment of them in various shapes and sizes. And the New Mexican micaceous clay bean pots made by master potter Felipe Ortega and other artists, available through Cafe Pasqual’s in Santa Fe, are in a class of their own.
And one last note, on food safety: If you’re not sure a pot is lead free, you can do your own due diligence with a home-testing kit, available at hardware stores and online sources. This Food and Drug Administration update has more advice for consumers.