My 36" corner build with Argentine Grill and spit roast

[UtahBeehiver]

Not sure but you can smell it when the carbon/smoke residue starts to burn off and oxidizes.

[Gulf]

In most cases there will also be absence of visible smoke coming from the flu/chimney.

[jonv]

I read somewhere that soot burns off at 500C+

I've got a roaring fire in my oven right now and the dome is partially cleared - it's about 525C on the interface between black and clear.

[david s]

The carbon burns off at around 300 C. Maybe your reading is in F.

[jonv]

Don't think so. Maybe what I read is wrong but it seems to tally with my measurements...

[jonv]

Just thinking that perhaps the soot has started to burn off at a lower temperature than measured but takes a little time so that the completely clear part of the dome has been heated further by the time it has burnt off entirely... still, my dome appears completely black until well north of 300C.

[SableSprings]

My readings with my IR gun have my oven clear by the 675F-700F range (~360C-370C) ...be aware that if you are taking an IR reading of the dome with a fire going, you might be getting some temperature bump from the fire plume. Also, remember that the IR gun has a very limited distance in which it's accurate. The IR is taking a reading from a cone of space in front of the sensor...the farther away from the surface you're pointing at, the less accurate it gets--fast. If you're not holding the gun within 5"-6" (13-15 cm) of the surface to be checked, you can be way off the actual temperature.

Although the laser pointer portion of the gun makes it feel like you're right on target...the laser is totally separate from the IR sensor system that actually takes the reading. Also, if I remember correctly from elsewhere, clearing in the oven is not necessarily the actual burning of carbon but primarily breaking down (by heat) of many "organic binders" that create that black soot/creosote film at lower temps. We call it carbon...but I'm not sure that's as accurate as calling it a creosote & organic film...it's just easier to say. Creosote starts burning at 451F (233C), so by the time the firebrick surface is up to 300C, that black crap is well on its way to gone.

And really, does it matter exactly at what temperature the oven clears? As long as we don't have a limp pizza or soot raining down on our bread loaves , we should be pretty happy cooking in our FABULOUS wood fired ovens. I do like to count on oven clearing as an "event" in my normal oven heat loading/firing process before a bake, but it isn't necessarily critical to my process. I think it's more important that we let the temperature equalize in the oven--so the bricks are evenly heated throughout--prior to baking or roasting without a flame. I've baked a lot of great bread in an oven that didn't get cleared.

[david s]

I bake bread in an uncleared oven all the time. Because my oven is small I generally cook only one or two loaves at a time and therefore just fire the oven until the top begins to clear. This takes one hour from light up and uses very little fuel. I also don't bother removing the coals. Once the door is in position the coals die through lack of oxygen anyhow. I place the bread on stainless trays which takes the sting out of the floor which would otherwise burn the bases of the bread. It also removes the need to clean the floor prior to placing the loaves in the oven. Just need to make sure the flames have died completely or you get a smoky flavoured bread, not very pleasant. This method seems to work on a consistent basis. The oven certainly would not have equalized in temperature, but the bread comes out pretty good.

[SableSprings]

I agree David, just getting the oven up to baking temp and not equalizing works well for a couple loaves of bread. I've done the same thing when pressed for time and it works great for me too. When I made the "equalizing" comment in my previous post, I was thinking more of when I'm baking two or three batches of bread in an afternoon (15-20 loaves). I have an ash dump, so I pull out the ash and any remaining coals and want to be sure the cooking floor temp is reasonably consistent for my bread loading directly on the bricks. That's why I have been happy with doing an hour equalization of the oven after I've pulled out the ash/coals.

...and I totally agree that baking bread with "smoke" is just bad...

[jonv]

Good point about the range SS - for obvious reasons (such as the thermometer melting or my arm scorching!) I am a fair distance from the target so perhaps I was picking up a higher temperature. And perhaps a lick of flame interfered with the readings. Still, over numerous fires now it seems I have to get it really hot before it will clear. In any event, once it is properly saturated it will coook the pizzas in 90 seconds and cook quite a few before it shows any signs of cooling down

[Bauldy 2]

Wow plenty of info thanks again I try to stick arm in and point later to dome high point once fames died down pretty much top to bottom temps within 30 deg or so except the floor .Had it up to 400 deg yesterday let it die down and oven door worked well no moisture from insulation since initial fire also insulation does not get even warm remains at same temp so 5" of insulation definitely good decision.will try to get oven up to 450 today to see if soot clears got till thurs before rendering will stop Tuesday to allow oven to cool off .Although if insulation still shows no temp increase at 450~500 deg c then is there any need to allow cooling before I render? Any advice boss?

[jonv]

Seems to be working well. You're right about the insulation - even with 4" there is little temperature rise on the outside, 5" will keep the heat in for a long while

[Bauldy 2]

Thanks boss oven cleared as you said started at about 10: 30 got temp up to 450 oven before 12:30 the soot cleared threw in a shop brought frozen pizza tasted better than usual so all good then had a whole chicken roasted from 4pm til 6 cooked at about 300 deg c tasted excellent but a bit of a cheat because it was a roast in a bag .so no pics as both meals ready made.im not starting cooking until all work completed, as I want to use prep area ovens and grill as a outdoor kitchen.
il fix steam vent tomorrow and finish my convertible coffee/ dining table .i should get the stainless sheet an box section so I can make glass oven door and Argentine grill.il post pics of first pizza when I make one.thanks again for advice now oven nearing end I need to read up on cooking roasts as the deal was I could have oven if I did all the cooking at weekends so long as all building work was finished

[Bauldy 2]

Should I push on with the fires to 500 deg or leave it till after I've finished render what do you recommend boss?

[jonv]

You've got the insulation on there so can take the fires as high as you like in modest increases. When you put the render on I would then leave it for at least one week, perhaps longer, before having some long but not so hot burns to drive the moisture gently out of the insulation. You'll know when it's done as the render will get hotter than expected due to steam until the moisture is gone.