Dave, so after you have filled the chamber with flame (after the first 45 mins), do you then keep feeding the whole area with more wood for the next 45 mins?
That does sound like a lot of wood.
Yes, but once it’s pretty hot each bit of wood makes a lot of flame. You fill the whole chamber with flame not wood and feed it with nothing thicker than your wrist. My ovens ( retty small @ 21” internal diam) use 4 kg wood in 1.5 hrs to get to 400C.
Lets face it, wood is probably the least expensive consumable in the WFO process, so don't skimp on it. For a cross-draft WFO, light the fire under the flue, gradually push it back to the rear of the structure, if you get flame out of the flue then ease up a bit.
Lets face it, wood is probably the least expensive consumable in the WFO process.
Good point. It's also interesting to look at Dave's wood usage figure of 4kg to get the oven up to temperature, which initially didn't sound like very much wood to me.
So I took the internal diameter of mine (80cm), cubed it, and divided it by the cube of Dave's oven diameter and multiplied it by 4. This gave a wood consumption figure for mine to get to the same state of 13.5kg which sounds in the right ball park.
I used the cubic function on the grounds of approximating the ovens to hemispheres, where the volume will be a cubic function of diameter = a bit of old school geometry!
I think it depends on the type and amount of wood more than the size - smaller pieces will release their BTUs quicker, which is good. I usually start with alder (sometimes pine) to just get the fire going, then once close to cooking time I switch to maple so I don't have to attend to it as much. I use splits that are generally 4-5 inches by 6-8 inches, sometimes more, sometimes less. I have a 7 ton powerhouse that is seldom stopped cozzy.org/best-log-splitter/ Typically 8-12 pieces depending how long we're cooking. Usually more with the initial fire, 3-5 during the pizza making.