wood-fired wood oven, as shown on Tales from the Wild Wood

[SimonFisher]

The second episode of the BBC television series Tales from the Wild Wood (BBC4, Wednesday 24th October 2012) featured a wood-fired oven being used by two chaps in a woodland in Wales to prepare a wood-fuel product that was essentially cut pieces of coppice that as a result of drying in their oven for eight hours was extremely dry.

One of the benefits of drying to them was to reduce the mass of the final product making it lighter to transport. They also said it burned much hotter than regularly seasoned timber.

They claimed it was almost 0% moisture content - although as they showed one of the chaps measuring it using a moisture meter in the end-grain, I'm not convinced they actually demonstrated that. My moisture meter instructions state, and my own experience confirms that end-grain measurements are inaccurate and you ought to measure across a freshly split face of the log being measured.

I am however interested in the wood-fired smallish oven they were using. Does anyone know if such things are commercially available? I assume large industrial kilns are used for much of the kiln-dried firewood available and they might well be heated using some other form of fuel or energy source. This one interests as it didn't appear too large and was heated by burning wood.

[SimonFisher]

Be aware that the super-dry wood burned a lot hotter. If you used it in a woodburner, which isn't designed to operate at high temperatures, you might damage it.

I did wonder about that. They reckoned the super-dry hazel could burn at almost 400 degrees C compared to 200 degrees for that which had been normally seasoned. I wonder what sort of temperature our wood-burner reaches at present? We have broken a couple of fire-bricks over the years - whether temperature or someone ramming in a too-large-piece-of-wood I don't know. It was burning toasty hot last night - never seen that on a thermometer scale though Maybe I should get a thermometer.

[RichardKing]

Wood dried to almost zero moisture content is certainly not "new", it was previously used along with charcoal to fire blastfurnaces in The Weald several hundred years ago.

[Bulworthy Project]

We run our woodburner partly on "brown ends" (the wood that doesn't quite make it to charcoal). That is basically the same as the super dried wood that they were making. You do want a multifuel stove to burn it in. The set up that they were using looked quite expensive compared to using a charcoal kiln and then stopping the burn before it is complete. Even stopping the burn early, you will end up with some charcoal in the centre of the kiln, but that can be used in the woodburner too or you could save it for the summer and have a barbecue.

[Terry]

I believe they were claiming 2% moisture on the program, but what happens when you take it out of the 'oven'?
I am sure that unless you go to great lengths it will absorb moisture from the air, resulting in a significantly higher MC.
What does air dried wood get to - 15 - 20% I believe at best, at which point it is in balance with atmospheric conditions??

Presumably they are looking to market the fuel for some industrial process rather than domestic use??

[Whatisheatnow]

I have two large old cylindrical iron oil tanks which have been empty for years. They are each about 1,200 litres (260 gallons) capacity and are about five feet long and three feet in diameter. Would it be possible to use them as wood fired wood ovens if an end was cut off each and made into doors? Are they too big or would the drying process take a very long time? Would it be possible to place them side by side, fill them with logs and use the one fire in the space beneath them? What external insulation would be needed to keep temperature high? Would plenty of soil heaped all around them except for the chimneys and doors do the job?

[Andy M]

Not quite the same thing, but look at http://www.firespeaking.com/portfolio/o ... rrel-oven/

[cinimod]

I think Living Woods Magazine had some info on them last year - looks like they have an article from the Wild Wood too
This one is similar, but it is not the one - The Exeter Retort - http://www.biocharretort.com/


http://www.living-woods.com/subscriptions/

(or £5 for 3 issues via this link; http://ccstandard.securewebservices.co. ... index.html)