Oaxacan pottery is known for its bold colors and folk art figures, but the everyday pots that are used for cooking are built with coils. Women do almost all of the pottery, from collecting and purifying the clay to construction, glazing and firing. There are three types of Oaxacan pottery -- the black, the green and the red. The black pottery gets its color and name from the firing process, which creates a deep ebony finish. These pots are intended for decoration only as they are too fragile for everyday use. Green pottery is named for the emerald green glaze they are coated in. The glaze is relatively modern. The red pots are the once-fired clay of the region, which takes on a reddish, terra cotta color when fired. The oldest style of pottery in the region, redware pots are still used for cooking and daily tasks in Oaxacan homes.
The Oaxacan potter works with clay she digs from the ground and works until it is the right consistency by drying, sifting, and remixing with water. She flattens a handful of clay until it is the size of the pot base she wants. Adding a "longa", a coil of clay, to the pot base, she joins and smooth the clay together. She uses a corn cob, her fingers or a gourd fragment to work the moist clay as she adds coils. Any air bubbles can hold steam during the firing process, which will result in cracking or even an explosion in the kiln. A poorly constructed pot is good for nothing but rubble. As the pot grows, she alternatively makes the long ropes of clay and joins them to the pot rim until she has reached the size and shape wanted.
The construction of the pot complete, the potter will begin the finish the surface. Using fingers, a scrap of leather or a curved piece of gourd with a smooth surface, she will scrape and smooth the clay until all joins are invisible and the walls are a uniform thickness. Experience tells her how thin to make the walls. Too thick and the pot will take longer to dry before firing. Too thin and the wet clay pot will collapse on itself. Some Oaxacan pots are built three to four feet high to hold drinking water. Even these are built with the coil method and smoothed as they are worked on.
Firing an Oaxacan coil pot is usually done in a wood-fired kiln that is partially underground. A fire is built around the pots, and then covered with stones and broken pots to hold in the heat and smother the flames. The resulting bed of embers is allowed to slowly die out, a process that can take up to two days. The pots that are to be glazed will be fired again after glaze is added. Black and red Oaxacan pottery is only once-fired. Once-fired pottery is fired once and the resulting pots are hard, but porous. Twice-fired pottery is glazed after the first firing and fired again to liquify the glaze, which is mostly glass, resulting in pots that can hold water without evaporation. The black Oaxacan pottery is also polished with a rag and a little oil to bring out the glow of the oxidization created in the firing process.