IR Thermometer and residual heat

[talisker63]

Well, got a IR Themometer delivered Friday and used it last night (fateful night of The Crack )

What a great device any Australians who need one, let me know they are on eBay for $65. Measures -50c to 500c, thats about 950F

Now the floor got to 860F and the walls were at 900F+. Once the fire died down to coals the temp dropped to 750F and we cooked pizza (pictures in the pictures section). It was immensely valuable to see the different temperatures in each section of the oven and monitor them as they fell. Made the whole process a lot easier.

Next morning, when I checked the oven was at 175F on the floor and 210F on the walls. Does this sound reasonable? How do you keep enough heat overnight to cook next day? The oven was fired for about 1.5 hours.

cheers

[talisker63]

Re: IR Thermometer and residual heat

Hey

I just became a Peasant

[gjbingham]

Re: IR Thermometer and residual heat

Great question. Cook pizza earlier and bake/cook later, or refire the oven the next day. It takes a lot less wood. I'm living the same conundrum.

[Xabia Jim]

Re: IR Thermometer and residual heat

Seems like it dropped a fair amount. How much thermal mass do you have?

Did you seal off the door and chimney well?

I will throw in a large log and let it smolder overnight. We cooked for 5 days straight and I would just keep the fires burning.....

what brand and model of thermometer is that? seems like a pretty good price!

[Frances]

Re: IR Thermometer and residual heat

If you want enough heat to cook with the next day, (without adding more fuel) you may need longer firing times. My oven seems to need 2 or 3 hours till the bricks are really saturated with heat, which would make it possible to bake the next day.

So far I've been making pizzas for lunch, with about the same heat up time as you had, baking in the afternoon, and cooking dinner in the evening.
Still, the heat you have left would be enough for a nice stew or some slow cooking.

If you give us the info on your oven door and mass and etc, I'm sure you'll get lots more advice...

[talisker63]

Re: IR Thermometer and residual heat

The thermometer is a AJH mini laser gun model 8871. They also have a model above which measures to stupid temperature. It's really easy to use and switches from Celsius to Fahrenheit so i can post meaningful numbers to my American friends

The door on my oven was supplied as part of a kit and is just sheet metal. I think next time I will fire for an additional hour and see what that does. I would love to cook pizza one evening and then lunch and bread next day. Ambitious?

cheers

[CanuckJim]

Re: IR Thermometer and residual heat

Single Malt,

You might want to consider seriously coating your sheet metal door with a sheet of refractory insulation. The difference in heat retention overnight is remarkable.

Jim

[jeff]

Re: IR Thermometer and residual heat

TK63, you Peasant you.
Congrats, eh.
Mate, in addition to what has been said already, do you still have moisture in the masonary? That could influence the cooling curve.
Our oven seems to drop 1.5*C /hr, after 24 hr. I don't know if that is good, bad or indifferent, but would like to know.
Just for the hell of it, wrap your door in a metre or two of alfoil, to test for heat losses there. I reckon you'll find CanuckJim is on the money.
Welcome eh, and stay in contact.
teach.

[RCLake]

Re: IR Thermometer and residual heat

I fired my oven up the last two nights for pizza and on Sat morning the air temp was 360F. I have a thermometer going thru my wood door that I've glued 3" on insulation board to. This morning my oven was 250F because I didn't close the door past the chimney. The fire was going real good still at 10:30 last night so I didn't want to close it completely.
I have a 2" ceramic blanket on it for my curing fires. I'll be checking for cracks and then will install the rest of my blankets, should be 4-5" overall then.

[talisker63]

Re: IR Thermometer and residual heat

Whoa! Jeff you lose only 1.5C per hour! That is awesome.

CanukJim I will try and insulate the door some. What like some cement sheet or similar? Stupid question but does it mater which side I insulate?

I'm thinking of adding another layer of render, would this help also? I noticed that the outside was still quite hot when firing. Maybe another blanket and then another render? Or is that just overkill?

cheers

[jeff]

Re: IR Thermometer and residual heat

TK63.
Misleading figures. (Should have been a politician, eh).
2 points.
1. That measurement was after 2 days, with an oven temp of 125 and air temp around 20(all temps in Celcius, sorry).So not a big gradient.
2.I went off half-cocked. Flamin impetuous boy!

So more useful figures from the last day or so.

7pm, 450 (pizza time)
10pm,277 (burnt pizza-roll time)
noon, 208 (temp check after 14 hr)
4pm, 197 (temp check, + cold stew in).
5pm, 176 (stew check 'n muck about).
7pm, 171 (meal out)
9pm, 177 in oven, 75 in 'foyer'.
So after an initial fall averaging 60/hr over 3 hrs, the next 24hr dropped by 100C, or 4/hr averaged.

So tomorrow, I should be able to do slo-cooked boar over maybe 8hrs. What do you reckon Inishta?
Fellers, this line of thought is not mere academia. I reckon a pizza night generates enough stored energy for at least 2 more night's fodder.
As always, criticism of my post is welcome. (NOT! no one enjoys criticism!!)
But I'd love to see other's data, eh.
teach.
ps . Final reading for the night @9.40pm (air temp 23C).
Oven, 176, "foyer" (or is that 'atrium')? 75
more later. t.

[Inishta]

Re: IR Thermometer and residual heat

Need to make a trip to UK to get the thermometer then I can contribute...........

teach.......Wrap her up nice and snug and overnight should be a sound proposition..............or all day...........whatever!

[jeff]

Re: IR Thermometer and residual heat

Inish,
Before god (ahh, James), gave us the WFO, I'd been looking at American sites re smoking and slow cooking, and I really wasn't set up for it. Always a bit hit'n miss with temps.
Brick ovens are becoming SO predictable that I'm about game enough to leave a big chunk of animal protein alone all day, knowing that when we come home, it will be just so good.
As an update, after 47hours from pizza, the atrium was 50C, oven120.
90 minutes later, and I am about to check the damage: feeling confident.
teach.

[Inishta]

Re: IR Thermometer and residual heat

teach, over here a very popular dish is Tandir lamb. It is large joints, usually leg, that is put in stainless steel covered roasters and left to cook all day at low temps in the WFO. Incredibly falling off the bone tender. Served with hot pide bread and a salad.........maybe a cold beer...........a first class luncheon.

[mieno]

Re: IR Thermometer and residual heat

Talisker
Is this IR gun the one from gastools? Is 500 degrees celcius enough do you think?
I was originally looking at the cheap digital thermometers with dual k type thermocouples (also on ebay) however the thermocouples only went up to 200 degrees celcius and none of the suppliers can source higher rating couples.
Thanks.