Debunking the Terracotta Mythos
The sun has yet to awaken, the moon just rose as a wink on the horizon, and the roosters are making that heinous sound only roosters can make, disturbing my first cup of coffee. Excuse me while I get that cup…
I want to talk about terracotta and it’s classification as an earthenware clay body. In ceramics we have hundreds of clays available to us, but all of them fit into one of two categories; earthenware, or stoneware. The difference between earthenware and stoneware is the maturation temperature, more easily termed as low or high fire clay. Low fire clays, having been fired to their maximum temperature (anywhere from 1800-2100°F) remain porous, while high fire clays vitrify when fired to higher temperatures ( 2200-2500° F). Since clays have many “ingredients” that are specific to their particular region, all clays have a different temperature range, but all can be classified as either low fire or high fire clay. Terracotta is technically a red earthenware, a low fire clay containing between 5 and 10% iron.
The meaning of “terracotta” is “baked earth” in Italian. Many people mistakenly use the words “terracotta” to describe anything made of clay from anywhere in the world, whether it is low or high fired. But as we are beginning to understand, terracotta is an actual clay body itself. It is abundant and utilitarian, can be found on every continent, and has been used for millennia to create irrigation piping, garden pots, and roof tile. It is best to speak of terracotta regionally, for example Mexican terracotta is essentially the same as Italian, but fired at a lower temperature. Another mistake about terracotta is that it is weak. In many places in the world it is hard to find even enough fuel to bring the fire up to the maturation temperature of the clay. If the temperature that matures (hardens, strengthens) the red clay is 1980°F, but the fire only reaches 1800°F, what happens? You have immature, under-baked pottery that is susceptible to cracking and doesn’t last very long. This happens all over the world…many places simply don’t have the wood to do the firings, so they will use whatever they can to heat up their pots, resulting in a market in which one terracotta pot will last only two years and the one next to it will last two hundred… it just depends on the fire and country of origin.
The next time someone says to you that terracotta is junk and won’t stand the test of time, tell them in all confidence that it depends on where it is from and how it was fired. Then you can say that Eye of the Day garden design center only sells authentic Italian Galestro terracotta, mined for five generations from the same clay deposit, and fired to perfection. You can always depend on Eye of the Day for the highest quality in garden design products.
Hope this was informative. See you all next month!