Author Topic: Why install thermocouples if I have an infrared thermometer?  (Read 3396 times)

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Offline Fio

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Why install thermocouples if I have an infrared thermometer?
« on: March 20, 2006, 09:04:25 AM »
I'm in the process of building my own brick oven.  Part of the planning process involves whether to install thermocouple temperature probes.  The plans call for them, but it seems to me that, with the availability of an infrared thermometer, you don't need them.

Am I missing something here?
Since joining this forum, I've begun using words like "autolyze" and have become anal about baker's percents.  My dough is forever changed.


Offline Bill/SFNM

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #1 on: March 20, 2006, 09:23:59 AM »
IR sensors can only read surface temps. The most important temp in this kind of oven would be the cooking surface which is easily read with an IR sensor. The deck may be very hot, but may not be indicative of the temp of the entire thermal mass of the oven. If you're cooking one pie, this may not be much of a consideration, but if you're cooking many pies, the energy stored within the mass of the oven is important for maintaining the temp of the deck. My oven has a probe embedded in the brick of the dome. It is very useful, but not essential, in letting me know when my oven  is ready. After many firings of the oven, I now have a pretty good feel for when it's ready, but it was nice to have while I was learning.

Another reason for some kind of probe in the oven is if you are using it for baking bread with the door closed so you can monitor the air temp without having to open the door which lets out heat and moisture.

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Offline Dieter01

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #2 on: August 06, 2012, 04:20:42 AM »
I don't have an IR meter but I do have a datalogger and everything I need (except probes) to get sensor readings on my planned oven. I have read quite a few threads now and I've tried to figure out what I need to measure. Right now I am leaning towards the following:

Two probes between Super-Isol layer and oven floor, one on the left (about 1/5 from the side wall) and one on right (also 1/5 of the diameter from the side wall). The objective is to be able to get a reading for when the oven is "saturated" with heat. I am not sure how heat is distributed through the floor so maybe it would have been enough with one in the center but unless you have experience that tells me otherwise I will go with two.

I also plan to fix a short tube through the door that can fit a probe angled slightly up (to avoid conflict with food inside). This way I hope to monitor oven temperature for baking etc. The same probe will be long enough so that it can be placed lying on the floor when the door is out in order to get a reading of the floor's surface temp.

Sound OK? I see a lot of people install probes in the ceiling but I am not sure what I would use it for...

Offline Jet_deck

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #3 on: August 06, 2012, 09:14:36 AM »
One thing you should realize is that the probes, in the location that you are suggesting putting them, aren't going to give you anything accurate.  You most likely are going to read the temps where they were 45 minutes ago, not where they are now.
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Offline Dieter01

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #4 on: August 06, 2012, 10:48:34 AM »
Ok, but not sure if I understand why... I was hoping to avoid drilling a hole to place the probe inside the oven floor, bending the probe and using thermal cement. Do you consider that to be an essential step?

Offline TXCraig1

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #5 on: August 06, 2012, 10:58:15 AM »
I personally wouldn't mess with. It's not mission critical and just one more thing that can break. As Bill noted, with a little experience, you will go by look and feel.

What is the maximum temperature the thermcouple can measure?
I love pigs. They convert vegetables into bacon.

Offline Jet_deck

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #6 on: August 06, 2012, 11:12:04 AM »
Ok, but not sure if I understand why

Because of the mass of the oven.  It could take 30 or 45 minutes for an increase in heat to travel to the thermocouple...
I think they would be fun bells and whistles, but not necessary.
Her mind is Tiffany-twisted, she got the Mercedes bends

Offline Bill/SFNM

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #7 on: August 06, 2012, 11:17:01 AM »
As Bill noted, with a little experience, you will go by look and feel.

Six years later, I don't even bother to look at the built-in probe. No idea if it even works.

Offline Dieter01

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #8 on: August 06, 2012, 01:14:26 PM »
Because of the mass of the oven.  It could take 30 or 45 minutes for an increase in heat to travel to the thermocouple...
I think they would be fun bells and whistles, but not necessary.

My intention was to learn when the oven had stored the maximum amount of energy (and not just made it to maximum surface temp inside the oven). In other words: Do I need to keep a fire running for 1 hour or 6 before the floor has the same temperature at the top and bottom - to sort of find a point of diminishing returns. Its going to cost me $40 worth of equipment and very little effort so I figured it might be worth it to accellerate my learning curve a bit. I am sure that after firing up the oven 5-15 times I'll stop using it and go by feel.

Does that make sense or am I on the wrong path here?

Offline Dieter01

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #9 on: August 06, 2012, 01:22:51 PM »
Ohh and the temp rating is about 2100 deg F with continous use.


Offline TXCraig1

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #10 on: August 06, 2012, 01:42:32 PM »
If its not going to bother you when it's broken, why not put it in? If it will bother you when it stops working, leave it out.
I love pigs. They convert vegetables into bacon.

Offline Jet_deck

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #11 on: August 06, 2012, 01:50:19 PM »
... it might be worth it to accellerate my learning curve a bit....


How good is your dough?
Her mind is Tiffany-twisted, she got the Mercedes bends

Offline Dieter01

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #12 on: August 06, 2012, 02:05:20 PM »
If its not going to bother you when it's broken, why not put it in? If it will bother you when it stops working, leave it out.

Hehe! I like how you think  :D

I am pretty sure I want to put a probe in there, just wasn't sure about where I should put it and if I should aim for placing it inside the floor itself or below (first option slightly more labour intensive and I also think the second option will give me a more valuable reading).

How good is your dough?
I am planning to use frozen pizza.

j/k... I am sure there will be an even bigger learning curve when it comes to the cooking. This place seems like a wealth of information though and I am already planning crazy things like planting San Marzano tomatoes in the greenhouse next season, buying type 00 flour and putting beer or ice cubes in the dough... Looking forward to good times ahead :-)
« Last Edit: August 06, 2012, 02:11:35 PM by Dieter01 »

Offline Bill/SFNM

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #13 on: August 06, 2012, 02:56:10 PM »

I am planning to use frozen pizza.


Seriously?  :o

What temps are you planning to use for learning your oven? What kind of frozen dough? Is it designed for WFO temps?

Offline TXCraig1

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #14 on: August 06, 2012, 02:58:35 PM »
I am planning to use frozen pizza.

I've heard of people going to jail for using frozen dough in their WFO.  :'(
I love pigs. They convert vegetables into bacon.

Offline Jet_deck

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #15 on: August 06, 2012, 04:32:37 PM »
I am planning to use frozen pizza.

j/k... I am sure there....


j/k = just kidding.
Her mind is Tiffany-twisted, she got the Mercedes bends

Offline Bill/SFNM

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #16 on: August 06, 2012, 04:42:06 PM »

j/k = just kidding.

You kids and your crazy jargon. Hey, get off my lawn!

parallei

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Re: Why install thermocouples if I have an infrared thermometer?
« Reply #17 on: August 06, 2012, 04:51:02 PM »
Quote
I am planning to use frozen pizza.

j/k...

 :-D :-D