Temperature graph of the firing in October 2003

(cheminee = chimney, alandier=firebox)

The preheat went well and everyone is in good spirits, so on the second Friday we let the temperature climb furiously... Not a reasonable thing to do if we don't want to break everything. The 3m high stacks of pots don't like that very much! So we calm down and start the temperature climbl gently. The temperature probe behind the hearth (in red) ended up by melting down at 1200° and the stokers continued stoking by looking at the flames, listening to the kiln and the smell of the smoke, with a squint at the pyrometric cones from time to time through the furnace...

Phases of the firing:
1/ The Preheat:
This phase corresponds to drying out the kiln.
Duration: about 10 days, until Thursday.
Type of wood used: Trunks, very large branches and stumps (oak).

2/ The Small fire:
During this phase the temperature goes up to about 1000 degres Celcius. This has to be done slowly since most of the pots are completely unfired. It is also important to accumulate lots of embers in the firebox.
Duration: about 3 days (Friday to Sunday).
Type of wood used: Large pieces of oak.

3/ The Large fire:
Climb up to 1300 degrees at the front and as near as possible in the rest of the kiln. The wood is supplied through an opening above the heap of embers and it explodes practically instantly. We select wood that produces the longest possible flames in order to heat the back of the kiln. At this point you can see the flames coming out of the other end of the kiln, up to and including the chimney.
Duration: about 2 days (Monday and Tuesday).
Type of wood used: Split oak, acacia, birch, and some faggots 1m50 long.

4/ The cooling down:
Temperature descending as slowly as possible. The chimney and firebox are hermetically sealed. This has to be done rapidly when the kiln is at its hottest at the end of the firing.
Duration: about 3 to 4 weeks.