Author Topic: IR thermometer/ baking stones  (Read 534 times)

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Offline dulcevita

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IR thermometer/ baking stones
« on: July 17, 2014, 06:40:03 PM »
Just scored an old bakers pride with no stones for cheap. I know it gets up to 550 but after that I'm just not sure how hot it can get. I have my eye on an IR crafts man therm  MODEL 50466 it runs about 68 bucks, I'm guessing this will do the trick. Also as far as stones go I'm kinda clueless for right now I'm trying to choose between a Cordierite, FibraMent and Mullite grog mixture type stone. Any tips would great.


scott123

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Re: IR thermometer/ baking stones
« Reply #1 on: July 17, 2014, 06:58:58 PM »
$68 is too much to spend on an IR thermometer, imo.

Best IR gun?

What model is the Baker's Pride? Gas or electric?

If it's a full sized gas deck, they'll probably cost you the most, but the lower conductivity of the fibrament allows for better balance at higher temps.  The Whitacre Greer firebricks have even lower conductivity (better), but the small sizes of the bricks could make them trickier to work with.

As far as the 550 peak temp goes, that's usually pretty flexible.  Just swap out the thermostat with one that goes to 650.

Offline Donjo911

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Re: IR thermometer/ baking stones
« Reply #2 on: July 17, 2014, 07:01:26 PM »
I ask because I don't know...(and I see Scott 123 is on this page)
If it's a commercial oven that operates at 550-ish  - why wouldn't steel work for the floor there too?  (depending on what you were trying to produce)
Too conductive?  Isn't at some point just a question of bake time and temperature?
With all the chats about boscitti, and breakage, and low conductive ceramics,.  etc.  I'm almost sorry to ask - but wouldn't an oven with "the right properties" at a fixed temperature be good for NY pie?


It's one of those if it's good for the goose (home) it's good for the gander (restaurant) questions.


Simple answer? I do not study thermal dynamics.  I'm almost positive this is a weak question. I've just always wondered.


Cheers,
Don
Few great accomplishments are achieved single-handedly, Most have their Norgays.
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Offline TXCraig1

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Re: IR thermometer/ baking stones
« Reply #3 on: July 17, 2014, 07:11:07 PM »
$68 is too much to spend on an IR thermometer, imo.

Best IR gun?
If it's a full sized gas deck, they'll probably cost you the most, but the lower conductivity of the fibrament allows for better balance at higher temps.  The Whitacre Greer firebricks have even lower conductivity (better), but the small sizes of the bricks could make them trickier to work with.

Actually, they are almost identical at ~0.69 W/m-K
Pizza is not bread.

Offline dulcevita

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Re: IR thermometer/ baking stones
« Reply #4 on: July 17, 2014, 07:14:30 PM »
$68 is too much to spend on an IR thermometer, imo.

Best IR gun?

What model is the Baker's Pride? Gas or electric?

If it's a full sized gas deck, they'll probably cost you the most, but the lower conductivity of the fibrament allows for better balance at higher temps.  The Whitacre Greer firebricks have even lower conductivity (better), but the small sizes of the bricks could make them trickier to work with.

As far as the 550 peak temp goes, that's usually pretty flexible.  Just swap out the thermostat with one that goes to 650.
Its a suppppperr old  MO2T model its from 1977 I think. At least that's what it say's on the elements. Its a counter top model, the same size as the bakers pride p-18 model I think. Oh and it says it tops out at 700.

scott123

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Re: IR thermometer/ baking stones
« Reply #5 on: July 17, 2014, 07:23:29 PM »
I ask because I don't know...(and I see Scott 123 is on this page)
If it's a commercial oven that operates at 550-ish  - why wouldn't steel work for the floor there too?  (depending on what you were trying to produce)
Too conductive?  Isn't at some point just a question of bake time and temperature?
With all the chats about boscitti, and breakage, and low conductive ceramics,.  etc.  I'm almost sorry to ask - but wouldn't an oven with "the right properties" at a fixed temperature be good for NY pie?

Don, in most markets, gas is cheaper than electricity, so gas deck ovens are typically the norm.  Gas decks have no broiler burners.  There's one burner, and it's located under the hearth. They typically use a combination of metal deflectors and side wall channels to take the heat up and around the stones to bake the pizza from above, with levers that are supposed to adjust the amount of heat going to the top, but these attempts at redirection are only effective to a point.  As you start ramping up the thermostat, eventually the stones start baking the bottom of the pizza far faster than you can get the top to bake.  Pale tops/burnt bottoms. 

Steel accelerates bottom browning. In a typical gas oven that overfavors bottom browning at higher temps, steel would exacerbate the issue and burn the bottom of the pizza even faster. In these instances, the lower the conductivity the better.  A lower conductivity stone allows you to run the oven hotter (faster top bake), while slowing down the transfer to the bottom of the pizza and achieving better balance.

Now, in theory, if, say, you only had access to steel, it might be possible to ramp up the deflection enough in a gas deck to accommodate the extra conductivity of steel, but it would entail some pretty advanced thermodynamics kung fu, and a lot of work. In a bottom heat scenario, it's always better to have less conductivity in the stones.

scott123

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Re: IR thermometer/ baking stones
« Reply #6 on: July 17, 2014, 07:46:38 PM »
Its a suppppperr old  MO2T model its from 1977 I think. At least that's what it say's on the elements. Its a counter top model, the same size as the bakers pride p-18 model I think. Oh and it says it tops out at 700.

While my thoughts on countertop wattages are evolving:

http://www.pizzamaking.com/forum/index.php?topic=32682.0

the watts on this particular model, are, imo, especially egregious.  For an oven like this, 1/2" cordierite is your best bet for a replacement stone, but I'm not entirely certain it's worth spending the money for cordierite stones.

You're going to find different opinions on this, but if your home oven reaches 550 and has a broiler in the main compartment, when you combine it with a $25-$50 steel plate, it will outperform this oven.

If you are hellbent on spending the money on cordierite to take this back to factory specs, then I'd track Bobino's process as closely as you can.  If he can do 4 beautiful 4 minute bakes in 53 minutes, then, with your wattage, perhaps you can do the same in an hour and a half.

I would also take a look at the testing that Barry has done with this oven:

http://www.pizzamaking.com/forum/index.php?topic=16602.0
« Last Edit: July 17, 2014, 07:56:42 PM by scott123 »

scott123

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Re: IR thermometer/ baking stones
« Reply #7 on: July 17, 2014, 07:48:54 PM »
Actually, they are almost identical at ~0.69 W/m-K

Maybe we're interpreting this chart differently:

http://www.pizzamaking.com/forum/index.php?action=dlattach;topic=23596.0;attach=71260;image

but I read it as W-G having a slightly lower average thermal conductivity.

Offline Donjo911

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Re: IR thermometer/ baking stones
« Reply #8 on: July 17, 2014, 07:58:04 PM »
Don, in most markets, gas is cheaper than electricity, so gas deck ovens are typically the norm.  Gas decks have no broiler burners.  There's one burner, and it's located under the hearth. They typically use a combination of metal deflectors and side wall channels to take the heat up and around the stones to bake the pizza from above, with levers that are supposed to adjust the amount of heat going to the top, but these attempts at redirection are only effective to a point.  As you start ramping up the thermostat, eventually the stones start baking the bottom of the pizza far faster than you can get the top to bake.  Pale tops/burnt bottoms. 

Steel accelerates bottom browning. In a typical gas oven that overfavors bottom browning at higher temps, steel would exacerbate the issue and burn the bottom of the pizza even faster. In these instances, the lower the conductivity the better.  A lower conductivity stone allows you to run the oven hotter (faster top bake), while slowing down the transfer to the bottom of the pizza and achieving better balance.

Now, in theory, if, say, you only had access to steel, it might be possible to ramp up the deflection enough in a gas deck to accommodate the extra conductivity of steel, but it would entail some pretty advanced thermodynamics kung fu, and a lot of work. In a bottom heat scenario, it's always better to have less conductivity in the stones.


That helps a ton! Thanks!  I admire your detail and willingness to share. Thanks!
Altho - Kung Fu is very interesting  ;)


Cheers,
Don
Few great accomplishments are achieved single-handedly, Most have their Norgays.
How do you spot a Norgay?
You start with the people with the funny names.

Offline TXCraig1

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Re: IR thermometer/ baking stones
« Reply #9 on: July 17, 2014, 08:11:32 PM »
Maybe we're interpreting this chart differently:

http://www.pizzamaking.com/forum/index.php?action=dlattach;topic=23596.0;attach=71260;image

but I read it as W-G having a slightly lower average thermal conductivity.

First and foremost, a difference of 0.04 W/m-K (6%) is all but meaningless in this context. And, unless you are baking at 18C (64F), the conductivity is probably not the figure presented as the average. Why they would test firebricks at 10-30C, I don't understand. It's likely that the conductivity continues to increase with temperature up to some point and then start to fall.  I don't know what temp Fibrament tested their product at, but it wouldn't surprise me if it was something closer to 250C. Take all this together, and the one thing you can conclude is that there is not enough information to conclude there is a meaningful difference.
Pizza is not bread.


scott123

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Re: IR thermometer/ baking stones
« Reply #10 on: July 17, 2014, 08:44:56 PM »
I don't know what temp Fibrament tested their product at, but it wouldn't surprise me if it was something closer to 250C.

It would surprise me.   In my experience, unless temperature is stated, thermal conductivity values tend to be measured at room temp more than not. If a specific application of a material requires temperature specific measurements, then those are provided next to the room temp values, but single conductivity values seem to favor application agnosticism.  In other words, just because fibrament is utilized at higher temps, the odds that the company that tested fibrament's conductivity actually tested it at higher temps and provided only that value for that higher temp- those odds are quite minimal, imo.

Until I see greater specificity in fibrament's numbers, I have no issue with perceiving their present figure at face value- .69 and also perceiving it as being greater than .65 (or even .62).
« Last Edit: July 17, 2014, 08:48:29 PM by scott123 »

Offline TXCraig1

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Re: IR thermometer/ baking stones
« Reply #11 on: July 18, 2014, 12:41:05 AM »
It would surprise me.   In my experience, unless temperature is stated, thermal conductivity values tend to be measured at room temp more than not. If a specific application of a material requires temperature specific measurements, then those are provided next to the room temp values, but single conductivity values seem to favor application agnosticism.  In other words, just because fibrament is utilized at higher temps, the odds that the company that tested fibrament's conductivity actually tested it at higher temps and provided only that value for that higher temp- those odds are quite minimal, imo.

Until I see greater specificity in fibrament's numbers, I have no issue with perceiving their present figure at face value- .69 and also perceiving it as being greater than .65 (or even .62).

You have made some pretty thin arguments over the years but arguing that 0.69 is somehow meaningfully different from 0.65 needs an electron microscope to be seen. I have to admit that it is fun watching you grasping at air to avoid having to admit you are wrong.

Tell me that when you wrote "The Whitacre Greer firebricks have even lower conductivity" that you knew the difference was only 0.04 W/m-K.
Pizza is not bread.

scott123

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Re: IR thermometer/ baking stones
« Reply #12 on: July 18, 2014, 01:16:09 AM »
Tell me that when you wrote "The Whitacre Greer firebricks have even lower conductivity" that you knew the difference was only 0.04 W/m-K.

In the past, whenever a material had more than one value for conductivity, I had always quoted the lowest. Prior to today, I had been using .625 as the value for W-G, but when you brought up the topic, I, in an effort to avoid contention, met you in the middle, so to speak, and went with the 'average' rather than .625. That was in error. .625 was the number I had in mind when I said "WG firebricks have even lower conductivity," and I should have stuck to my guns.  Thank you for helping me find some backbone in this regard :) Let the record show that when I said 'average,' I was erroneous.  I consider, and have always considered W-G to have a conductivity of .625.

Regardless of whether or not W-G bricks are .625 or .657, lower, even fractionally lower, is significant. The only potential deck material with a lower conductivity than W-G and Fibrament is Biscotto, and Biscotto is neither logistically nor financially viable for domestic NY style pizzerias.  The hair splitting that I'm doing here relates to awarding the crown to the viable material with the lowest conductivity.  While it does lean a bit towards an ideal, there are real world ramifications.  Most gas deck ovens are, as I said earlier, intrinsically imbalanced at higher temps.  Neither W-G bricks OR fibrament resolves this imbalance. Your average deck oven owner can't purchase .6-.7ish decks and expect balanced bakes at higher temps. They are only a part of the potential solution. Because of this innate shortcoming at resolving balance issues, every fraction of a fraction of decreased conductivity matters.
« Last Edit: July 18, 2014, 01:53:35 AM by scott123 »

Offline TXCraig1

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Re: IR thermometer/ baking stones
« Reply #13 on: July 18, 2014, 02:14:22 AM »
In the past, whenever a material had more than one value for conductivity, I had always quoted the lowest. Prior to today, I had been using .625 as the value for W-G, but when you brought up the topic, I, in an effort to avoid contention, met you in the middle, so to speak, and went with the 'average' rather than .625. That was in error. .625 was the number I had in mind when I said "WG firebricks have even lower conductivity," and I should have stuck to my guns.  Thank you for helping me find some backbone in this regard :) Let the record show that when I said 'average,' I was erroneous.  I consider, and have always considered W-G to have a conductivity of .625.

Regardless of whether or not W-G bricks are .625 or .657, lower, even fractionally lower, is significant.

I see. You thought the difference was a whopping 0.06 W/m-K. And that is "significant?" (let alone 0.03) Are you sure about that? Have you done the math? Tested side by side? On what are you basing your assertion?

Pizza is not bread.

scott123

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Re: IR thermometer/ baking stones
« Reply #14 on: July 18, 2014, 02:57:07 AM »
I see. You thought the difference was a whopping 0.06 W/m-K. And that is "significant?" (let alone 0.03) Are you sure about that? Have you done the math? Tested side by side? On what are you basing your assertion?

0.0668 W/m-K :) The W-G bricks transfer 9.6% less W/m-K than Fibrament.  In an imbalanced system where neither material is up to the task, I'm going to take whatever lack of conductivity that I can get.

Roughly speaking, 1/2" soapstone, at 550,  (at 6 W/m-K) can do about a 4 minute bake, while 1/2" cordierite (at 3 W/m-K) can do 8 minutes.  That's a difference in 4 minutes of bake time and 3 W/m-K- 1.33 minutes per W/m-K, 80 seconds per W/m-k. Using this as a guide, that's 5 seconds trimmed off the bake time for .0668 W/m-k. And that's laboring under the assumption that this is relatively linear, that the relationship between W/m-K and bake time between 3 and 6 W/m-K will track the same way between .625 and .6918.  Based on the way it tracks for steel, I can pretty much guarantee you that is isn't linear, and that, as you go lower, differences in W/m-K produce proportionately greater reductions in bake times.

Even if the W-G bricks can trim, say, only 5 total seconds off the final minimum bake time of a gas deck oven, it's 5 seconds that I'll gladly take. When you have imbalance, any balancing force, regardless of how small that force is, is useful.

Offline TXCraig1

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Re: IR thermometer/ baking stones
« Reply #15 on: July 18, 2014, 09:57:47 AM »
What do you estimate the bake time to be at 550F on a 0.625 W/m-K surface?
Pizza is not bread.


 

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