How terracotta pots are made

Wet the clay

Dug clay containing kaolinite, quartz and iron oxide is mixed with water to a workable consistency. The iron is what will turn it reddish brown in the kiln, and a bad balance of ingredients gives weak, brittle pots.

Knead out the air

A pug mill churns the clay while a vacuum pump draws out trapped air. One maker pulls enough vacuum to remove 99% of the bubbles, but not so much that it drags salts to the surface as a white bloom.

Press into steel molds

Hydraulic presses force slugs of clay into precision steel molds that set the rim, wall and drainage hole. One machine line turns out more than 200 pots an hour, all within a millimeter or two of each other.

200+ pots an hour

Dry them slowly

Fresh pots sit in drying rooms that control heat and humidity for a few days to a week. Rushing this step makes them crack or warp in the kiln.

Fire the kiln

Dried pots are stacked into gas, electric or wood-fired kilns. Heat fuses the clay particles into hard ceramic, and the iron oxides react with oxygen to give terracotta its color. The body stays short of glassy, so it remains porous.

around 1,000 °C

Test strength and porosity

Sample pots from each batch are tested for strength, to survive shipping, and for porosity, to confirm the walls breathe. Most are left bare, and some are glazed.