|raking walnut shell coals prior to baking|
Recently in France, I saw a large community brick oven in Audrix started with wood but primarily heated with walnut shells, the byproduct of a locally abundance nut tree. The method used can be applied to any fuel source that would normally be smaller than is practical to throw into a heating brick oven.
The walnut shells are placed in a paper bag and the bag is place on the coals. Within a minute, the paper burns away and soon the super-heated walnut shell burst into flames filling the domed chamber.
|grape vine and olive tree prunings for fuel in Italy|
In Italy, the locals in the Amalfi coast, Umbria, and Tuscany, use prunings from grape, lemon, and olive trees.
The overall consideration is that the fuel not be resinous and be hard enough not to produce 'fly ash' which could drift both around the chamber during pizza firing and fly out of the chimney as sparks creating a fire hazard.