Author Topic: How long to fire up a wood-burning oven?  (Read 7623 times)

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Offline Bill/SFNM

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How long to fire up a wood-burning oven?
« on: June 20, 2006, 04:48:03 PM »
I wanted to start a new thread since the poster who asked for "experienced advice" on building a wood burning oven explicitly asked that the thread not be hijacked.

"Pizziaola" made the following statement in that thread:

Quote
I have a model 90 which is their smallest commercial size, but the best size for any kind of serious pizza baking. I can go months without using the oven and it never takes more than 1 1/2 hours to get up to full temp (about 900-1000 degrees). When I'm using it on a semi regular basis, it takes 45 minutes to an hour to crank up.

I also own the same Earthstone model and was astounded by this statement. It takes me quite a bit longer to fire it up when cold, at least 5-6 hours. Granted I live at a high altitude so wood burns cooler. Also, I deliberately built my oven with the maximum thermal mass (e.g., I have a 1" thick plate of steel under the brick floor.). But I still can't how that explains this difference.

May I ask Pizziaola if you can describe your firing process and where and how you are measuring that temperature? I hope JPY is lurking and can also help me understand the difference.

Bill/SFNM



Offline vitoduke

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Re: How long to fire up a wood-burning oven?
« Reply #1 on: June 20, 2006, 05:07:19 PM »
Hi Bill--- I have the Forno Bravo Premio 100. It takes me less than 1 hour for it to come up to temp. I recently started using a weed blow torch to start the fire, I no longer have to use any paper to start the kindling.  I just put some kindling on the hearth with several small logs and light them with the torch.---Mel

Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #2 on: June 20, 2006, 05:27:23 PM »
Vitoduke,

Thanks. I use somethin similar - a cactus burner - to get the logs going. But I need to know a few things, if you would be so kind: how many logs do you start out with? What is your target temp? Where are you measuring it? With what are you measuring it? Thanks!

Bill/SFNM

Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #3 on: June 20, 2006, 06:13:46 PM »
Hi Bill,

5-6 hours? YIKES that is off the chart too long. Here's what I do and it works every time.

1-  In the center of the oven, directly under the dome, build a small fire with paper and kindling. Use sticks or fat wood. You can also use a firestarter brick and add the kindling on top.
2-  When the kindling catches on fire nicely, add 3 more small pieces of wood (about 2 or 3 inches wide and about 1/2 inch thick) Cut side down to the flame.
3-  When those are burning well, add 3 or 4 more 3-4 inch wide pieces of wood, cut side down and allow them to also catch flame well before finishing the fire
4-  This process should take about 20 minutes
5-  Once the base fire is fully engulfed, add logs in a triangular or square of overlapping pieces of wood, cut side down. The wood should be about 4 to 6 inches wide. Overlapping the ends of the wood
      creates air in the fire which helps it to burn faster. Build this fire pile about half way up to the dome of the oven.
6-  The fire has been properly built when abundant flames lick the dome.
7-  Keep the flames at this intensity--licking the dome of the oven (but not coming out of the door of the oven--make sure the fire is built smack in the middle of the oven--if you can't reach it, use the wood-peel that Earthstone supplies with the oven to position the wood properly)
 

Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #4 on: June 20, 2006, 06:23:32 PM »
Pizziaola,

Where are you measuring the temp and with what?

Thanks.

Bill/SFNM

Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #5 on: June 20, 2006, 06:57:13 PM »
Sorry about that, I hit the wrong key!
Now, where was I...

8-  It is essential to keep that fire burning like hell, licking the top of the dome until the oven dome becomes totally white. You will also notice, the the remaining sides of your oven are also now white.
     When the dome of the oven is white, it means that the oven has been properly fired up. A white dome indicates a temperature of about 1000 degrees+ up there, and a baking temperature of about   
      850 near the fire.
9-  Once the dome is white, push the fire on one side or another of the oven (I usually alternate)with a heavy metal bar or stone material bar (I use a 5 foot x 3 inch leftover piece of stone from an old    countertop (they sell odd pieces of the stuff in stone cutting shops for very little money--and sometimes for free). Add larger logs, cut side down onto the ember mass.

10- This entire process should take about 1-1 1/2 hours for an oven that hasn't been used in a while.

The model 90 usually has a temperature range of about 850 degrees--right next to the fire to about 500 degrees at the outer edges of the oven, to around 400 at the mouth. Larger models have more flexibility with ranges to about 350 at the door.

Firing up this oven (or any other wood-burning oven) in this manner, fires it up evenly, without cold spots, and maintains the even temperature throughout cooking time. Because the fire was started in the center of the oven, the top and bottom are evenly fired. An even heat sync is essential to trouble free cooking. Firing up the oven to one side or another, never attains an overall even heat sync.

When cooking pizzas, which rely on the heat sync of the stone hearth, firing the oven up to its full potential is necessary to get the even and concentrated heat for crusts that will bake quickly--getting the characteristic oven spring, but not too fast so that the bottom burns when the top is not cooked, or when the top burns and the bottom is not done.

Bake bread or roasting in these ovens does not require the same intensity, they rely more on the air temperature of the oven. Even hearth-baked bread, bakes at a much lower temperature, and when flame is not present.

There is no way around properly firing up the oven. Even daily usage requires at least, 30 minutes to re-establish that dome heat and bottom heat by building a fast, hot fire that licks the dome, and gets it white hot. That is your sure indicator that you are ready to rock.

A few tips:

The wood has to be hard wood that is fully dried. Not all wood has the same BTUs. The smaller the cut, the better it burns in this situation. I have my firewood supplier double split my wood for me, he calls it "restaurant split" because this is how the restaurants with wood-burning ovens order it. Don't add larger logs until there's plenty of embers going. Embers provide the real sustainable heat, building an ember bed is really important to maintaining temperature without burning log after log. At that point, flames do not contribute to the heat as much as the concentrated heat sync of the embers.

Always use the cut side down of the log as it takes more time to penetrate bark, this is the same when you add a log at a time on the ember pile to keep it going.

I realize that for most, they will only be using the oven to cook a few pizzas, I tend to make mine work for a number of hours when I use it, so, I want to get the maximum out of it without throwing a lot of wood on.

This method is the same method recommended for larger commercial models where they must maintain temperature all day and not use up so much wood. By firing up the oven properly, once all of that stone is evenly fired, it will maintain that heat, evenly and without as much wood-- and that also is the mark of an efficient oven.

Does that help?


Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #6 on: June 20, 2006, 07:00:50 PM »
I use an infrared thermometer and measure the heat right at the dome, right next to the fire and at 6 inch intervals across the oven floor from that spot to the outer oven wall. Also, closest to the door. When I measure a large commercial oven, I use 12 inch intervals.

Offline JPY

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Re: How long to fire up a wood-burning oven?
« Reply #7 on: June 20, 2006, 07:12:28 PM »
Generally a Model 90 will take about 1 1/2 to 2 hours.  Depending on the kind of wood you use can change the heat up time too.  Of course where you read the temp from is another point to look at. Is it from the dome or floor? Generally when the inside of the dome turns back to it's original color from the black soot then the oven is on it's way.  Also try not to add too much wood in the oven.  For an oven of this size, which is almost 3 feet in diameter, you probably do not want more than 4 large pieces of wood at one time for the initial start up.  What I look for is a nice big flame in the middle of the oven that hits the dome very hard and has little nicks of the flame comming out of the oven opening.
-JP-

Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #8 on: June 20, 2006, 08:03:31 PM »
Pizziaola,

I pretty much have been following the same procedure as you for the past 5 years, but I do use a cactus burner for igniting the logs. I always use hardwood (pecan and oak) but am using larger pieces than you are. After about three hours, the dome has turned from black to white, but if I bake at this point, the deck as measured with an IR thermometer is about 800F, which is too cool for me. Perhaps the big thermal mass I have under the brick takes longer to stabilize and allow the deck temp to get up to 950 which is my target.

Perhaps the altitude and thermal mass are the major reasons. I'll use smaller pieces of wood and see if that helps.

Did you install the probe that comes with the oven into your dome? What does that read when you are at baking temps?

Thanks for all the information.

Bill/SFNM

Offline JPY

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Re: How long to fire up a wood-burning oven?
« Reply #9 on: June 20, 2006, 08:26:41 PM »
Bill, for the temps you are going for use something around 2 1/2 inches in diameter and 12 to 18 inches long.  These will get the oven up to temp faster. But your point about the increased thermal mass makes sense. You may have a "big sponge" under your deck that is soaking up all the heat.  I had these guys from Naples over at work the other day and they made some pizza, we had the oven temp gauge at 775F.  Which means that the surface of the dome was probably at 900+.  They had their own dough so I'm not sure what was in it.  It came out pretty good.  2 to 2 1/2 min pie.   Maurice likes the oven in the 600 to 650 range for the smaller ovens and 700-750 in the bigger ones.  Of course he's not too much of the Neapolitan style pizza person.  But what he does always come out great. :chef:
-JP-


Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #10 on: June 20, 2006, 08:51:31 PM »
Hmm, how can I explain this?

When you use the torch to heat up the oven, you are only heating the air and not the stone and that is one of the reasons it takes so long. The process that I explained is essential to firing up the oven from the STONE out. Think of it this way, the torch merely warms up the air inside, it heats up the surface of the stone, but not the stone itself. For that to happen, the fire must be built in center and made to touch the top of the oven. What happens next is physics (which I not so inclined, but do understand what is happening). When you have a solid, hot fire built into the center of the oven that licks the top, the action of the fire directs the heat from top to bottom and all around the oven walls evenly. Think of the action as sucking the heat from top to bottom and back. This giant "ball" of heat penetrates the stone mass evenly and effectively. The embers have more concentrated heat than flame, so the more embers that form, the faster and greater your heat sync will develop.

Because the oven has been fired evenly, less wood will be needed to maintain the heat mass. This is where the quality and thickness of the refractory material comes into play--better quality retains more heat, thicker walls holds it longer. Plus, using a blow torch is propane, propane produces moist heat and moisture on the stone, also, it does not have the BTUs of hard wood. You want to stay with the dry heat that wood produces to penetrate faster. I've worked with a lot of gas-fired stone ovens, and they work well too, but they do cook just slightly slower and produce a slightly thicker crust because there is a touch of moisture in the air of the oven. Most of the better gas-fired ovens have additional burners under the oven floor which also helps a lot.

Regarding the wood, Oak is good, it burns sustainable BTU's which is what you want to maintain the oven, Pecan, burns hot, without as much residual BTU power--it is better as a flavoring agent and great for starting the fire along with the oak. I use a mixture of oak and almond for the same reasons, although, almond wood has more sustainable BTUs than beech. I would just up the ratio of oak to about 2/3 to pecan to maintain.

while I'm not surewhat the steel plate beneath your oven does or doesn't do, it shouldn't really affect firing up the oven. Perhaps altitude has something to do with it, but even at 3 hours, that is a totally unacceptable amount of time to get up to temperature for a model 90.

I seriously doubt you want a temperature of 950 on the floor of the oven, that approaches dome temperature which should be at around 1000 degrees when the oven is fully cranked for pizza.
Anything over 850 degrees will most likely produce thermal runaway pies ie: burnt.

850 to 700 degrees will produce the best results.  Plenty of professional pizzaiolos will brag that they are cooking their pies at 1000 degrees, but it simply is not so, the pies would all be burnt to a crisp.

As for built in oven thermometer probes, I don't have any and don't need them. I can tell how well my oven is fired just by looking at the interior and the ember bed. Before the advent of all these measuring devices, pizzaiolos had to learn about their ovens, to intimately be acquainted with all of "spots". I like the visceral quality of cooking without temperature gages and following the noble tradition of knowing my oven. However, that being said, I do use the thermometer when I've got something very specific going on and on occasion to verify my intuition--and I have used it to verify the zones in the oven. You should too.

Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #11 on: June 20, 2006, 09:47:25 PM »
Sorry, you misunderstood me. I only use the butane torch for a few minutes to get the logs started.

I definitely want a deck temp of 950F. I use a highly-hydrated Neapolitan-style dough using Italian 00 pizzeria flour with a Camaldoli starter which loves to bake for about 60 seconds. The crust is not burnt - just the char marks that characterize Neapolitan pizza. I've experimented a great deal with a range of temps and 900F-950F gives me the results I want. 

My issue is not how to bake a pizza  - although I am still learning, I am VERY pleased with my results to date -  it was just wanting to explore why it takes my oven so long to get up to the desired temp. One reason, obviously, is that I am pushing my oven a lot higher than you are. We both have the same oven, but we seem to be cooking different kinds of pies.

Bill/SFNM

Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #12 on: June 20, 2006, 10:15:33 PM »
Oh, sorry about that, I was looking at those pictures that show a torch and an empty oven, so I guess that's how I got that idea.

Our oven temperatures are not that far apart, 100 degrees or less. How much of the oven floor do you get up to 950 degrees? I have a smaller portion close to the fire where I put the pies down for several seconds before I turn then and move them in a circular fashion out of the oven. I also use a very high moisture level in my dough--70 percent, but my model is not the Neapolitan one, I do not use 00 flour which would produce more tender results. Cooking time really depends upon what size the pie is, what dough formulation used and toppings and personal taste.

Anyway, back to why your oven takes that long to get up to temperature, it might take a little longer than mine, but shouldn't be any more than 30 more minutes to increase 100 degrees. I suspect it has more to do with the size wood you are using. Smaller pieces burn faster, and turn into embers faster thus increasing the heat mass faster. I still use the bigger stuff later, after I have attained the temperature I want, they work better at sustaining.  Also, it is a fact that the larger the oven, the better it maintains the heat mass. I use an model 160 that is just awesome to cook in, it can get up to 900 degrees easily but still has a much greater range of temperatures available in other parts of the oven. The model 90 can be a bit one dimensional in that respect, but hey, who has room for a 160 in their house--and it does take a lot more wood to operate.

I really do love my oven, even if it isn't perfect.


Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #13 on: June 20, 2006, 10:33:28 PM »
Thanks, Pizziaola,

That makes sense. I'll try starting with smaller pieces. I'll be firing up the oven again on Saturday will try it then. Thanks for your help.

Bill/SFNM
« Last Edit: June 21, 2006, 08:55:35 AM by Bill/SFNM »

Offline vitoduke

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Re: How long to fire up a wood-burning oven?
« Reply #14 on: June 21, 2006, 08:31:57 AM »
Hi Bill--- I usually start the fire with some kindling and 2 smaller logs. Within about 5 minutes, I'll start adding more wood. I have a Raytec MT6 infra red gun to measure temp. I'll start cooking when the dome is 950 degrees, and the hearth is about 900 degrees. The gun only goes up to 950, so the dome could be hotter. I also keep a live fire going during cooking to maintain temp.---Mel

Offline pizzanapoletana

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Re: How long to fire up a wood-burning oven?
« Reply #15 on: June 21, 2006, 09:02:26 AM »
Are you saying that you manage to build enough heat in the floor of a prefabricated oven after 1.5 hours from cold?

I'd love to test-bake in your oven. I have tested an Earthstone oven (i am pretty sure it was of that brand) near Pittsburgh in a domestic setting. The lady owner had fired up the oven, "like hell" for 3-4 hours from cold... I went there, the dome was clear (and high I must say) and I after baking only 1 pizza (and I mean ONE) the floor lost temperature and could not bake a second one properly. The owner then show me the building instruction from the manufacturer (that is where I remember reading the brand) and she confirmed to have used all material and techniques recommended....

Plus, At real 900-1000 F cooking temperature (floor and air around it) the pizza should cook in 45 second top (without thermometer). If cook in any longer it simply means that the floor is nowhere near that temp and/or the hot air hitting the pizza (radiant from the flame, dome reflection) doesn't also get to those temp.

It is as simply as that. More then reading a thermometer, it is important to check the cooking time.

Ciao

Offline Bill/SFNM

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Re: How long to fire up a wood-burning oven?
« Reply #16 on: June 21, 2006, 09:59:27 AM »
Marco,

That was also my reaction to such short heating times. That's why I started this thread.

Once my oven gets up to temp after 5-6 hours, it takes about 60 seconds for a pie to finish cooking. If I do try it fire it for less time, the floor does indeed cool off after the first pie. As mentioned above, I did not follow the plans - I overbuilt to maximize thermal mass and insulation.

If you are ever in this part of the world, I would be honored to have you drop by to test out my oven - I'm sure you could do much better than me! In return, I'll make you "authentic" American BBQ like you've never had.

Bill/SFNM

Offline pizzanapoletana

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Re: How long to fire up a wood-burning oven?
« Reply #17 on: June 21, 2006, 11:02:58 AM »
I'd love to try your BBQ.

I'll hold you to that!

Ciao

Pizziaola

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Re: How long to fire up a wood-burning oven?
« Reply #18 on: June 21, 2006, 01:57:18 PM »
With wood-burning ovens to say that mileage varies is an understatement. I can't vouch for the lady in Pittsburgh--even if she did fire it up like hell, if the fire wasn't set in the right place of the oven, the oven will cook unevenly, then there is type of wood which varies substantially in terms of BTU's. And, there is the moisture factor of the wood--how cured it is. I cook multiple pizzas in the model 90 and do not experience these problems. The model 160 that I use (not in my house!!) fires up in about 45 minutes to 950 degree--easily. Now, that oven is used every day, so the starting temp is already at around 450 degrees. The model 90 starts the day off at about 400 degrees when I use it for several days.  3-5 hours still seems way too long. But you do say that you live at a higher altitude? That may also be a strong factor as to why.

The main thing is that you get the results that you want and that is where it's at---hey can I come over for some BBQ some time?  :

Offline pizzanapoletana

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Re: How long to fire up a wood-burning oven?
« Reply #19 on: June 21, 2006, 02:16:38 PM »
With wood-burning ovens to say that mileage varies is an understatement. I can't vouch for the lady in Pittsburgh--even if she did fire it up like hell, if the fire wasn't set in the right place of the oven, the oven will cook unevenly, then there is type of wood which varies substantially in terms of BTU's. And, there is the moisture factor of the wood--how cured it is. I cook multiple pizzas in the model 90 and do not experience these problems. The model 160 that I use (not in my house!!) fires up in about 45 minutes to 950 degree--easily. Now, that oven is used every day, so the starting temp is already at around 450 degrees. The model 90 starts the day off at about 400 degrees when I use it for several days.  3-5 hours still seems way too long. But you do say that you live at a higher altitude? That may also be a strong factor as to why.

The main thing is that you get the results that you want and that is where it's at---hey can I come over for some BBQ some time?  :

Pizziaola,

I do undertsand about ovens, wood etc (that is my second job), so there was not issue with that. The oven was as hot as she could get it.  Again prove to me that you cook several pizza in 30-45 seconds each after the short time you have stated to warm up the oven, and then you will receive my public apologies and compliments as well as I would probably become a rep for the company you are talking about...  Also by stating that is the best wood fired oven available, I suspect that you have more then an interest in it or have not tried/seen a proper hand made neapolitan oven.

I will ask my last client in US to send me a video of him baking pizza in his Neapolitan oven as soon as he opens for business (hopefully beginning of July).