Wood stoves are charcoal breeder reactors powered by their own vaporized wood gas. The re-radiated heat from the ironwork is what gives them their extreme warmth. They are like many other fuel burners — stage one vaporizes the fuel and stage two burns the vapor — it’s just that both stages are in the same iron firebox.
When you start a fire you want to quickly get the stove up to temperature. Use small split logs and kindling sticks along with some kind of “candle” that burns long enough to get the flames going. Commercial fire lighters (kerosine wax bricks) or even just a bit of kitchen towel with a tablespoon of vegetable oil will do.
The kindling and your first log will burn hot and bright with an attractive yellow flame — like a campfire. At the end of this first burn you will build up a layer of red hot wood embers in the base of the firebox and the ironwork will be about half way to temperature.
The next stage and each stage after that is to put on a much smaller load — often I will just use a single large log — and leave the air intake or door ajar, temporarily. The hot embers will rapidly get the new log hot and the whole thing will instantly go from glowing red to an inferno in under a minute.
At that point you have achieved a self sustaining reactor. You can leave it running full throttle if you want the pretty yellow flames. It will only last 20 minutes though and all the energy will blast up the chimney.
Much better, and indeed the whole reason for having a wood stove over an open grate, is to now shut off almost all of the airflow to the firebox. Low airflow means the combustion goes right down — you may not even see any flames if you go super low — but it also means the stove isn’t being constantly cooled by a high volume of airflow.
If you balance it just right then the flame front of burning wood gas will sit above the logs and permeate the whole chamber. It looks like a cross between Aurora borealis and a Backdraft (1991) slo-mo sequence — a deep red wraith that flaps around slowly, completely unlike the sooty yellow flames you began with. You get a real feeling for how it’s the gas not the wood that’s burning. (Having a stove with a glass viewing window really opened my eyes to their operation.)
A single 10” log — quarter split from a 20” diameter ash tree and air dried for 18 months to <20% moisture content — will now produce 10kW for an hour or more and stay burning for eight. The fire will “keep” overnight and in the morning you can put on a new log, fire it up with the door ajar, and be back at full capacity in minutes.
What’s interesting is that if you run the stove in pretty mode — like a cartoon open fireplace with crackling and burning and yellow flames with the vents or even the whole front door open — you’ll notice that parts of the stove might not even get hot. The iron air intake grill on mine will remain at room temperature because although the flames are vigorous, the airflow is so fast it keeps the stove body cool.
Conversely, once the stove has been running for an hour in slow burn mode, the entire body is practically glowing and requires thick gloves to handle. It is wonderful.