Brick Oven Temperature Curve

[james]

We've had a number of questions recently on what the temperature curve looks like for a brick oven. While individual oven performance depends on a number of factors, including its shape, mass, insulation, the quality of the refractory material, and how long/hot you fire it, here is an architypical temperature curve. You can see how the oven heats up with a strong fire, where it peaks while you are cooking pizzas, and how long the temperature fall-off lasts after the fire has gone out -- for baking bread and roasting meat and vegetables.

Remember Peasants, this is part of your oven that you owe to the local lord to bake his bread. Ouch.

This is a curve based on my experience. How does this look to you? Remember, your mileage may vary.

Off topic; did you read that the union of concerned scientists helped pressured the U.S. government to change the "estimated" MPG for new cars to be more accure? New cars will carry the accurate MPG estimates in 2008 -- I have read that Toyota has a new Prius coming with better mpg in time for the new law. The current Prius claims 60mpg, and gets about 45mpg; still not bad.

James

[stuart]

Re: Brick Oven Temperature Curve

James,

Is this example based on one firing of yours or an average? What type of oven, Pompeii, Casa etc? What was the fuel quantity and did you add to it or burn just the initial quantity?

Let's hear it for the union of concerned scientists! Now if they could get the U.S. gov to take it's head out of the sand concerning man's impact on global warming!

[Ted Rosenberg]

Re: Brick Oven Temperature Curve

I don't have any fancy charts for you but I cooked on Sat night for about 4 hours and cleaned the oven out about 10:30 and closed the door. The next morning at 9:00 it was still 400 degrees. It is a Pompeii with two layers of thermal blanket and then 6 inches of vermiculite. Really holds the heat & doesn't take long to get up to temp.

[RTflorida]

Re: Brick Oven Temperature Curve

To add to Stuart's questions, were the coals left in the oven? Door in place the entire time after the fire burned down?
As you said, our mileage will very, but, just getting started with my fires, it will be nice to have something to compare to.

[maver]

Re: Brick Oven Temperature Curve

Adding data, James presents a graph with a burn to full pizza temperatures, then 1 hour later down to 550.

From my experience waiting for the oven to bake bread, from making pizza it's usually 30min for the wood to burn down to coals, rake the coals out, then wait 1 1/2 hours with the door off for the oven to drop to 550 - replace the door for 15" then bake bread at 600 (replacing the door allows the heat in the firebricks to heat the air better so the temperature bounces back up). By the following morning we are in the low 300s (with the door on the oven over night).

[james]

Re: Brick Oven Temperature Curve

Maver has it right. These are from my notes for the Casa90 in Healdsburg. That oven has a 1/4"-1/2" RefMix coating, and 1 1/2" firebrick splits below the cooking floor. I don't think I would do the firebrick below again.

This was a full burn up to pizza heat; four pizzas for the family, and then bread. I let the fire burn down, and just pushed it over to the side -- both because I am lazy, and because I did not have a full load of bread to bake.

My idea behind putting it in a spreadsheet and graphing it, was to give a visual representation to something that everybody who cooks in a brick oven understands intuitively -- that is helpful for folks who haven't yet had the pleasure of using a wood-fired oven.

There are a zillion variations on this curve, depending on how long you cook pizza or fire your oven, how quickly you rake out the coals, etc., etc. Jim's big bread oven definitely has a different curve. In fact, the curve will be different every time you fire the same oven. That's pretty cool. Now, you can meet somebody at a party and say "what's your curve?"

The graph is really easy. I am attaching the Excel spreadsheet (.zip).

It would be interesting to see how other people's ovens curve -- Casa compared with Artigiano, compared with Pompeii oven with half brick, compared with Pompeii oven with 1/3 brick, and so on.
James

[CanuckJim]

Re: Brick Oven Temperature Curve

James,

My immediate response is that my bread oven definitely has a different curve, but, then, how do I know for sure. I'll work with the spreadsheet and find out what's actually going on, rather than my usual "umm, that's about right" approach.

Jim

[Xabia Jim]

Re: Brick Oven Temperature Curve

Sounds like we could use some thermocouples and a chartplotter!

[james]

Re: Brick Oven Temperature Curve

Or Mississippi's. Of course at the higher temperatures, you would burn all the hair off your knuckles. :-)

One more thing. Ted, it goes to show there is no such thing as too much insulation. Two layers of blanket and 6" of vermiculite sounds great, and it really doesn't add that much more cost.
James

[arevalo53anos]

Re: Brick Oven Temperature Curve

My oven has 8 thermocouples installed in it, four in different levels of the hearth and the others distributed along the dome.
I used to write down oven temperatures to spreadsheets each baking time.
The next curves are there in some place of this site.
As asked for Xabia Jim, here these are again...

There is a lot more from these ones came <g>

Luis