Temperature ratings in wood-fired ovens

[david s]

Re: Temperature ratings in wood-fired ovens

After you have fired your oven many times you won't rely so much on temp gauges, because it will do the same thing. Most take 1.5 Hrs for heat to soak the bricks and around 1Hr for the inside to go white. For bread or roasts a cheap oven thermometer that goes inside the oven is quite accurate and measures the temp where you want it.

[joe bloggs]

Re: Temperature ratings in wood-fired ovens

I have read elsewhere on the forum that most people who install thermocouples tend not to use them after a few months when they have gotten to know their oven's characteristics. However, I am in a unique situation as the oven I am building will be used by a large number of cooks (at least 20) and I will have to have some way to tell them what temps/techniques they need for a particular dish or cooking style and have some way for them to verify that they are doing things right without any experienced eye to tell them if the dome is white enough or the flour burns fast enough. I hope this explains why I would like to install thermocouples. I want to put in two close together about half way up the dome on one side, one measuring the inside of the brick and one the outside. Will this work for the above mentioned situation or does someone have a better suggestion? I have decided to go with thermocouples that are rated to 800? Celsius or 1472? Fahrenheit. Will this be high enough?
thanks, joe

[dmun]

Re: Temperature ratings in wood-fired ovens

the oven I am building will be used by a large number of cooks (at least 20)

Will they spoil the broth?

Your oven will rarely get above 1000 degrees f., and less on the inside of the brick. I think the only real reason to have thermocouples is to measure the saturation of the heat into the dome, so having two at different depths should be good. You may also want to consider planting a reserve pair while you're doing it, as they have a tendency to fail.

[joe bloggs]

Re: Temperature ratings in wood-fired ovens

No, I doubt they will spoil the broth - I didn't mean they would all be going at it at the same time! I was going to try to make the thermocouples removable, either by using proper stainless steel probes with thermowells, or by using copper or stainless steel tubes to slide the wires down. Do you know if this works?
Thanks for all the help!
joe

[Paul in Rockwall TX]

Re: Temperature ratings in wood-fired ovens

Regarding Heat underneath the hearth: I have 5" of structural concrete and about the same of vermiculite/cement under the 2-1/2 firebrick oven floor. I measured the temp of under the hearth today and it was 127F the morning after a pizza cook. Is that normal? right now it's still open, but I want to put a door on it but i'm concerned about how hot it will be for storing wood, etc. Do I need to add insulation under there? any thoughts are greatly appreciated.

[Lburou]

Re: Temperature ratings in wood-fired ovens

Regarding Heat underneath the hearth: I have 5" of structural concrete and about the same of vermiculite/cement under the 2-1/2 firebrick oven floor. I measured the temp of under the hearth today and it was 127F the morning after a pizza cook. Is that normal? right now it's still open, but I want to put a door on it but i'm concerned about how hot it will be for storing wood, etc. Do I need to add insulation under there? any thoughts are greatly appreciated.

You don't need to worry about the safety of storing wood under there until about 450 F.

[RTflorida]

Re: Temperature ratings in wood-fired ovens

Paul - I have a 4" slab and 3 1/2" vermicrete insulating layer. The day after a pizza firing the underside is about the same as yours 115 - 125F. Initiallly, say in the 1st month of firings, it was more like 140 -150F. Once you drive out the moisture entirely and everything has curred the temp drops quite a bit. My storage area has always had doors on it and always seems hot and stuffy, but it isn't from excessive heat radiating from the hearth. I'm sure ceramic fiber board leaches less but I am happy that the underside is in the 125F range. I run my oven hot (hearth temp around 800 -825F for pizza) and the air temp in the storage area is typically around 100F for about 6 months of the year even if the oven has not been fired for weeks.

I wouldn't be the least bit concerned with what you are seeing.

RT

[BurntFingers]

Re: Temperature ratings in wood-fired ovens

Ditto, we store some of our wood under the hearth. It gets nice and dry so it is easy to start. It doesn't get so hot to worry about ignition.

[Pareshdv72]

Re: Temperature ratings in wood-fired ovens

Hi everybody,

Ok I am new to this and would like to know what temp should i maintain to make a pizza and not burn the cheese

[BurntFingers]

Re: Temperature ratings in wood-fired ovens

If the bricks are white. I throw a teaspoon of bench flour into the oven and if it turns black right away it is too hot. When it slowly turns brown in few minutes it is just right. That is the temperature I maintain.

[Aussie Pete]

Re: Temperature ratings in wood-fired ovens

Hi all, this post hasn't been used for a while, but i think this is where this question belongs...input please..

is there a scale as to how the inside of the oven heat is maintained & dropped off, (bare with me....)

for example.. if an oven is a refractory cement mould 36" with a 19" x 11" door, and 3" fire brick floor and "x" amount of insulation on top of the dome (example only), is there a heat scale that it will hold temperature at, and a scale showing over time the drop off of heat. (Example...oven reaches 800F,... in half hour it is 770F, .....in 2 hours it is 640F, with no more wood added & door in place).
I hope i have explained that properly.

I'm guessing its just too hard to predict, with all the different types of ovens & materials.
Would such a scale be helpful in anyway, i'm thinking it might help to know when your good to go for baking breads, because you could get it to such a temperature, then check the scale and know that in say 3 hours, your good to start baking some breads. Am i over thinking the whole oven temperature idea too far, or would this "such scale" be useful. I'm also guessing that the more experienced oven owners here would know exactly when to cook anything, just in their head.

I suppose i'm a bit technical info brainiac...as in, i like to know all the facts and be in total control of what i'm doing. A bit anal you could say.
I'd also like to put thermocouples in my oven, but i'm a bit worried of their longetivity and their working life, i would hate to put them in the oven, only to have them fail 2 weeks later. I also would like to be able to place them in with the option to easily replace, can this be done without leaving gaping holes in my oven dome. The other reason, is i can acquire them easily and cheaply.

Sorry if i have missed this topic completely...."blame the novice guy"

[SCChris]

Re: Temperature ratings in wood-fired ovens

Pete,
The materials in the oven builds and fires vary too much to have a calculator that can do “what ifs” in a meaningful way. That said, with a bit of effort 5 to 8 degrees F or 3 to 5C per hour is very reasonable. As the oven matures, over the first 10 to 20 burns, the owner starts to understand the fire, the oven, and how they relate. If you insert thermocouples and monitor the temp over time you can start to get a feel for heat loss over time although an inexpensive IR thermometer will do the trick. The other part of the equation is the storage of the heat in the structure and this is dependent on the fire size and burn time and even how the fire is moved around in the oven or not.

Because of all of these variables, cooking / baking in the oven is more art than not. The most successful on this site are those with time using their ovens and those who have taken the time to know how to build and maintain a fire in their oven and how much their oven drops temp.

My description makes things seem more formidable than it really is and it’s really an example of how over thinking it makes the whole process daunting… It’s not. Once you start using the oven it’s not any more complicated than grilling or baking in the kitchen just a lot more fun and gratifying.

Chris

[Ken524]

Re: Temperature ratings in wood-fired ovens

Chris has it right. Every oven is different.
A few years ago I took regular temperature measurements (handheld IR thermometer) as my oven cooled. After feeding the numbers into a spread sheet, I generated some graphs.

As it turns out, the cool down schedule for a particular oven is very consistent and very predictable.

After using your oven a few times, you won't even need a graph or thermometer.

Here are the graphs I made:
http://www.fornobravo.com/forum/f17/...raph-4123.html

[edit] I wouldn't do this until your oven is WELL seasoned and cured. Your cool down schedule will be inaccurate if the oven isn't completely cured.

[Aussie Pete]

Re: Temperature ratings in wood-fired ovens

thanks chris & Ken, i'm in a bit of agreeance with you both, i probably am over thinking the whole temp thing. I suppose after i have played around with my oven a bit i will know my oven like the back of my hand....("where the hell did that vein come from" ).
Ken love your idea of the graph, i suppose thats the sort of thing i was thinking of, but my graph would probably only benefit me and be kind of useless to anyone else. If anything it would be fun to test & document for my own personal use.

[BurntFingers]

Re: Temperature ratings in wood-fired ovens

Hi all,

Yes, knowing your oven after a number of firings will surely help. Also realize that if you fire the oven, let's say every day for a week and never really let it cool down, assuming that you have plenty of thermal mass your results will be different from a firing from a cold start once a week. What i am saying is that you need to take into consideration all types of variables.

I know in my oven that if I fire it for pizza on Friday evening and fire it up again on Saturday morning to bake bread that afternoon the results will be different from just firing it on Saturday morning for pizza lunch and bread bake and roast beef or turkey in the late afternoon.
Bill