The clay
Everything begins from the galestro, the famous Impruneta clay.
During the summer the clay is placed in a large area to dry in the sun. All impurities like big stones, iron or plastic pices are removed by hand.
Then the clay is ground up in a hammer mill which also pulverizes gravel and little stones and inally mixed with water to create the wet clay mixture.
After this process the clay is ready to be worked. There are several methods to work the clay.
Moulds Work
The potters make use of plaster moulds whose sections are held together by long belts. The clay is pressed inside the moulds.
Today we have more than 500 moulds that are forged from ancient moulds.
Then, after hours or days, depend on the season, the mould can be dismantled and the vessel removed. The artisans have to touch up the ornaments by hand, removing the burrs and smoothing the edges.
Shell Work
Another working technique is called Shell Work, which consists of building the pot with coils (ropes of clay) by winding them around the outside of the mould.
The clay ropes are coiled around it in concentric circles and then spread over the top which will be the base of the pot.
At the end the mould is removed and the shell is left to dry before the decorations rims and borders are applied.
Coiling Work
But only few artisans today can make pots using the most ancient and difficult technique called coiling work, that is building the pot by coiling a rope of clay in an upward spiral, without any moulds.
These ropes are carefully coiled one on top of the other. Of course before adding other coils the underlying mass must have solidified. For this reason it’s possible to increase the height of pot by no more 15-20 cm per day.
The work proceeds very slowly and it can take several week to finish one pot.
The Drying
Before firing the terracotta pots must be totally dried.
First with the natural area for a few days, then in the drying rooms which are ventilated with warm air coming from the kiln.
During this phase, pots shrink by about 10% as a result of the water’s evaporation.
Once the pots are dried it’s possible to load the kiln.
The firing
Terracotta is fired at a temperature of about 1.040 C° (1.800 F°) and it takes a long time because the temperature must rise gradually in order to avoid thermal shock.
First phase lasts for 30 hours until the firing temperature is reached. Second one lasts for 8/10 hours, during which the pottery fired at the maximum temperature.
During this phase the pots change colour, turning the warm pick typical of Impruneta terracotta. The third phase is the cooling period during which the temperature drops slowly for about 48 hours. Only after these five long days it’s possible to open the kiln.
After terracotta has been fired and cooled it’s made wet for a long period in order to prevent cracks.