What fire wood should I not use?

[fullback66]

I have been reading the thread about the good kinds of fire wood people use in their WFO. Is there a bad kind of wood that should not be used?

I have been helping my buddy gather fire wood in Michigan. There is alot of wood from trees that died and fell down. Alot of the time the city came by and cut them up in smaller logs. They are nice and dry already. I am not sure what kind of trees they are. That is one nice thing about Michigan, there are alot of trees. Easy pickings. The best thing is they are free. They are all hard wood. deciduous trees.

That is why I am asking the question. Is there a tree that you should not burn?

I can drive down the road and fill a trailer with wood if I wanted to. In the city.

fb66

[edschmidt]

Re: What fire wood should I not use?

I burn pretty much any type of wood in my oven, I usually burn the first hour or so with scrap 2X4's left over from my job as a builder. I prefer to use hardwood for the later burn in order to controll the heat better, and pine tends to pop and throw charcoal all over the food.
P.S. Im in Rockford MI, where in michigan are you?

[edschmidt]

Re: What fire wood should I not use?

Oh, and to answer your question, don't use treated wood.

[RTflorida]

Re: What fire wood should I not use?

I have known people to have advers reactions to Walnut logs smoke, something about the oils in the wood. The usual Michigan trees (burch, oak, maple, any fruitwood, ash) should all burn well

[fullback66]

Re: What fire wood should I not use?

edschmidt, Dearborn Mi. Do you have an WBO?
Speaking of dead dry trees. I was taking my kids to school this morning when there was a whole dead tree right in the middle of the road. Time to start my buddies oven. The whole tree was right in the middle of the road.
fb66

[edschmidt]

Re: What fire wood should I not use?

I have a 36" diameter WFO

[beammeup]

Re: What fire wood should I not use?

I'd recomend against using rubber tree wood. Here in Thailand there is tons of rubber wood available. I tried it but it gives off a rubbery odour and black smoke. I am using eucaliptus and mango.

[rberg02]

Re: What fire wood should I not use?

For a reason I haven't fathomed , the instructions I received from Mugnaini recommended using only hardwoods and warned specifically against Poplar, Birch, and Pine. Friends of mine with AS ovens burn any kind of natural wood they like. I have two questions: Are the Forno Bravo refractory ovens made in Italy made of a similar material to the Mugnaini ovens? Second, does Forno Bravo have similar warnings against burning certain types of woods in their refractory ovens?

[dmun]

Re: What fire wood should I not use?

Out of curiosity, I went to look at the Mugnaini page to see what their ovens are made of. This is what they say:

Cotto Refrattario is Tuscan "refractory terra-cotta clay". For superior thermal efficiency, the Mugnaini ovens are made of 100% naturally quarried cotto refrattario.

This is good, because they seem to be made of fired refractory ceramic. They specifically say they are 40% alumina content, the same as low-duty firebrick. The curious thing is the phrase "100% naturally quarried" - to my best knowledge the alumina content of firebrick is a by-product of making bauxite into aluminum, and didn't exist in any quantity before the invention of electricity. Maybe the bauxite is so quarried.

But to answer the question: Poplar and birch ARE hardwoods, just not very dense ones. It will take more of those woods to fire an oven, but they will work just fine. Pine is a different story. It is so resinous that smoke from it can clog chimneys, and cause flue fires when used in a wood stove, which uses a constricted oxygen smoldering fire to keep going long periods of time. I don't think this would be a problem in an oven, which uses a hotly burning fire at all times. It might leave a slight turpentine taste in the food, I don't know. I tend to use pine (in the form of scrap lumber) just to get the fire going, and use hardwood logs later.

If fir, pine or spruce were an absolute prohibition for ovens, they couldn't be used in places like Colorodo, places where ALL the firewood is pine.

The one thing I don't know is how thick the Mugnaini ovens are. The FB ovens are about 2 inches thick. If your oven was much thinner there might be a question of thermal shock.

[gjbingham]

Re: What fire wood should I not use?

I agree. Unless the pine is very well seasoned, I wouldn't use it.

[rberg02]

Re: What fire wood should I not use?

Thanks. I kind of suspected that to be the case. I have heard that the bark on birch can also soot up chimneys. The Mugnaini ovens are also about 2" thick.

A little off-topic here and perhaps I should post this in another forum, but I'll give it a shot here first. I'm curious about the thermal efficiency of the floor in my Mugnaini oven. First a six-inch reinforced slab is poured. Over that goes six inches of dry sand topped with kraft paper and a final 3-inch slab on which the floor of the oven is set The dome is covered with a thermal blanket followed by a six-inch layer of insulating cement and topped with vermiculite (gable enclosure). How efficient is this setup and how does this compare with other ovens? Thanks.
Ron

[dmun]

Re: What fire wood should I not use?

Sand is a traditional insulator, but not a very efficient one. That said, it's better than nothing. Vermiculite/perlite concrete is much better, and the various engineered insulation boards are better still. I wonder why they would call for so much insulation on top, and so little underneath?

[CanuckJim]

Re: What fire wood should I not use?

Dmun has nailed it, as usual. From an efficiency standpoint, I'd have to say that the thicknesses and properties are almost backward. Cement slabs, even with so much sand, will wick heat from the floor, no matter what. It's recent common practice to use high heat ceramic insulation board under the oven floor to stop any heat sink developing in the slab.

Far as firewood goes, I built a AS oven, and I will burn just about anything to get the fire going, then switch to hardwoods like maple and oak. I have burned birch, but the bark is quite oily, so I tend to shy away from it when possible. Popular is fine. The one wood I will not burn is red pine because of the oily smoke and the lousy smell it produces.


Jim

[Mojoe]

Re: What fire wood should I not use?

This time of the year I'm burning anything dry... just wish the wife would quite asking me why the kitchen table is missing a leg.

[jwnorris]

Re: What fire wood should I not use?

<snip> Far as firewood goes, I built a AS oven, and I will burn just about anything to get the fire going, then switch to hardwoods like maple and oak. I have burned birch, but the bark is quite oily, so I tend to shy away from it when possible. Popular is fine. The one wood I will not burn is red pine because of the oily smoke and the lousy smell it produces.
Jim

We also need to remember the difference between a WFO and an AS bread oven. With the AS style the key is loading the mass with heat and then stabilizing the temperature.

With a WFO, we still cook with a live fire [at least some of the time] and the wood chosen has a greater effect on the final outcome of the food being cooked.

J W