Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Yes we also use the metric system here in the Philippines. It's difficult to accurately make the conversion from cuft to kilos. Mesquite is a great wood for these purposes. Most people would die for mesquite fire-wood. Just guessing but my 2 cuft is pretty close to your 30 kgs. Tman, you have a good point, propane. Yes, I am using my oven commercially and I quickly found out that sourcing fire-wood was going to be problematic. I plan to install a gas/wood combination burner in my oven for ease of start-up and to lower wood consumption.

I think you are still experiencing water being driven out of the refractory. It can take up to 5 or 6 good pizza temp firings to get it all out. You will use less wood once it is dry. You also experienced the joy of firing up a warm oven. It's so much easier to start a warm oven than a cold one. Keep firing and making pizza, sounds like everything is pretty normal.

[Tenorio74]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

30kg 's of wood!!?? Wow, thats' 66 pounds! Gotta be moisture. If a 30" dome takes almost a week of curing fires, I'd imagine a 51" would take more. I'd say forget going nuclear and just keep a fire going for a lonnnnng duration. That 30 kg's should last a while if you just keep it low and slow.

If you're going to be commercial, maybe you want to consider a propane torch/burner of some sort to help aid in the start-up process (if propane is cheaper). The mesquite should be really good for the purposes.

Tman, I missed your reply while doing work around here.... I also believe it's an insane amount of wood, but yesterday the beast just kept guzzling them up!

Maybe I need to move my fire to the side earlier on, to expose the center floor, or something. Actually, I have about an hour left here so I think I'll burn what I have left while the oven is still warm.

Start-up was easy.... newpaper donuts and kindling! The hard thing was the permanent feeding. Anyone remember the Munster's dragon's name (the one that lived under the stairs)???

I must admit the scary fires coming out the door do intimidate me a bit (funny 'cause I loved burning ants with my magnifying glass as a kid...)

[Tenorio74]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Tman, you have a good point, propane. Yes, I am using my oven commercially and I quickly found out that sourcing fire-wood was going to be problematic. I plan to install a gas/wood combination burner in my oven for ease of start-up and to lower wood consumption.

Lwood, Tman,

Are you referring to the hand held propane torches to blast larger pieces on start-up?

Lwood, by gas/wood burner, do you mean installing a gas line into your oven?

Gonna burn some twigs....

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

also, make sure the wood is dry. Very dry. Wet wood will make it very difficult to get to pizza temp. I always put a load of wood into the oven to dry once it gets below 400 or 500 F. The wood should immediately burst into flames when put onto the fire at above 500F. If it doesn't IMMEDIATELY burst into flames, it's not dry.

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Yes Ten, many people use a hand-held propane torch to get things started (especially if your wood is wet). And Yes again to running a gas line to the oven and installing a gas burner inside the oven permanently. FB just introduced a gas burner option in at least one of the new 2011 models. It's Italian made specifically for pizza ovens. I asked about FB selling the burner separately, but they don't. I have the link to the manufacturer if you want it.

[Tenorio74]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

also, make sure the wood is dry. Very dry. Wet wood will make it very difficult to get to pizza temp. I always put a load of wood into the oven to dry once it gets below 400 or 500 F. The wood should immediately burst into flames when put onto the fire at above 500F. If it doesn't IMMEDIATELY burst into flames, it's not dry.

Thanks for the insight. Are you referring to an air temp of 500F? I guess I'll have to bring in my home oven thermometer....

I have so far bought wood from two different suppliers... They both seem the same.

Only yesterday with the raging inferno did any wood thrown in light up fast, although they were only about 3" pieces max. I'm fluctuating between 2-3" sticks (diameter).

I'm not sure about the wood, I want to try another but I can't find any easily here, it is a bit frustrating. I'm not sure if it's not fully dry, or just the type of wood. The logs blacken and go golden coal on the outside, but don't really light up as I imagine. maybe it's wet wood, wood type or my poor technique.

I guess I'll just have to keep trying with other suppliers, or trying to find a different wood type to compare.

[Tenorio74]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

I do get the chinese dragon / flamethrower effect though.... It's pretty cool hehehehehe...

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

If they don't burst into flames immediately, I don't think they are dry. It's easy to test, either while you are firing or after for the next day. While firing and the oven is 500F or so, put some of your wood off to one side opposite of the fire. Very shortly they will start steaming if they are wet. Also you will see water coming out of the ends of the wood pieces. Wait for at least 30 min to and hour in the oven before you try throwing any of the drying wood into the fire. You should see the drying wood start to have little glowing embers on the drying wood before you toss them into the fire. They will even auto-ignite if they are dry enough, no matter what kind of wood it is. I once left them too long drying a large pile of wood and just as I first disturbed the pile of drying wood, it burst into flames and the whole oven was engulfed with flames. A little scary but I was diggin it after the first initial shock.

For the next firing, what I do is once I have finished everything for the night and the oven is down below 500F then I load the oven with as much wood as I can fit in the oven comfortably. Put the door on and leave it. So the next time I fire, the wood is nice and dry and ready to go. This make a huge difference in starting the fire and heating up the oven. You want the oven to be below 500F cause you don't want the wood burning jist drying. I find that if the oven is over 500F the wood starts smoldering and smoking and maybe burning even with the door on. My door is not that efficient. Otherwise you may have just ashes the next morning and no dry wood.

Test out the wood for dryness before you go looking for a new supplier. At least you will know the difference and maybe someone actually sells wood that is truly dry and you will know the difference.

[Lburou]

Autoignition temperature

Autoignition temperature

From Wikipedia, the free encyclopedia

The autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion. The temperature at which a chemical will ignite decreases as the pressure increases or oxygen concentration increases. It is usually applied to a combustible fuel mixture.
Autoignition temperatures of liquid chemicals are typically measured using a 500 mL flask placed in a temperature controlled oven in accordance with the procedure described in ASTM E659.

Autoignition point of selected substances



Temperatures vary widely in the literature and should only be used as estimates. Factors which may cause variation includepartial pressure of oxygen, altitude, humidity, and amount of time required for ignition.

• Triethylborane: −20 ?C (−4 ?F)
• Silane: <21 ?C (70 ?F)
• White phosphorus: 34 ?C (93 ?F)
• Carbon disulfide: 90 ?C (194 ?F)
• Diethyl ether: 160 ?C (320 ?F)
• Diesel or Jet A-1: 210 ?C (410 ?F)
• Gasoline (Petrol): 246?280 ?C (475?536 ?F)
• Butane: 405 ?C (761 ?F)
• Paper: 218?-246?C (424-474?F)
• Magnesium: 473 ?C (883 ?F)
• Hydrogen: 536 ?C (997 ?F)

For paper, there is considerable variation between sources. Part of this is because it takes longer for combustion to start at lower temperatures.[9]

Stating the obvious, dry wood in the oven below 450F....Paper is manufactured from wood, so has a similar autoignition point: About 450F

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Thanks Lburou for that. It appears my 500F wasn't too far off for drying wood.

[Lburou]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Thanks Lburou for that. It appears my 500F wasn't too far off for drying wood.

No offense intended, just dreaming of the day I'm drying wood in my own oven

[Tscarborough]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

You can fill the oven with wood at 900 degrees so long as you door it off. I generate almost 5 gallons of charcoal every burn by doing so. The charcoal works very well in my BBQ pit.

edit-I don't door it off at 900, I just door it off after the pizza is done. Most of the charcoal is generated in my ash can when I remove the coals to cook pizza.

[Lburou]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

You can fill the oven with wood at 900 degrees so long as you door it off. I generate almost 5 gallons of charcoal every burn by doing so. The charcoal works very well in my BBQ pit.

edit-I don't door it off at 900, I just door it off after the pizza is done. Most of the charcoal is generated in my ash can when I remove the coals to cook pizza.

Not picking a fight here and I don't doubt that depriving the oven of oxygen does what you say, but I'd be concerned about 'flashover'....A temperature where the combustible material will flash into flame even without oxygen....Don't know what that temperature is for wood though

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Yes Lee, that's why you don't want to put the wood in the oven above the flash over temperature. It will turn to charcoal. Maybe 500F is too high for you comfort level but in my experience 500F is usually where my oven when I am finished and the wood does smolder above 500F. But below 500F it seems to be ok. So put the wood into dry at 400F, make your self feel better. The time when I had the flash-over, my oven was at about 600F.

[lwood]

Re: Amount of wood to fire a 51 inch (130 cm) oven to pizza temps?

Don't get me wrong Lee, I appreciate your input and it backs-up what I am saying. But the wood will auto-ignite given the right conditions. I think the additional mass and all the other inaccuracies can explain any differences in the numbers. I admire your enthusiasm.