Temperature Experiments

The Naked Whiz

<p />I've been doing some playing around measuring temperatures of the ceramic shell vs. the air temperature and I thought you might be interested in this chart. What this shows is the dome temperature over time as the cooker is allowed to cool. The pink line represents what occurred when I heated up a cold large Egg to 700 degrees and immediately closed the vents and began taking measurements. The ceramic temperature was 160 F at that point.[p]The blue line represents what happened when I allowed the Egg to stay at 700 degrees for 7-8 minutes before I shut the vents. In this case, the ceramic temperature was 275 F.[p]I hope this illustrates why it is harder to drop the temperature if you allow the ceramic to heat up and why you should approach your target temperature from below so that you don't allow the ceramic to get too hot.[p]TNW

Unknown

The Naked Whiz,[p]Actually If I didn't know any better, I'd say that looks a lot like my paycheck history. I figure the left hand column is the dollars..and the bottom column is still time. I figure it's about one minute or so before the wife realizes it hit the bank account..and from then..it's just a steady decline..and if the chart continued..i'd say at about 25 minutes..it drops significantly..down to about 5 dollars..just enough for a weeks worth of god awful cheap store brand bologna and some day old bread. yummm...I love bagged lunch..there's just something about the fact that I alone...get to consume the last of my paycheck ever so slowly..savoring and swallowing..and licking my lips. On my birthday..she leaves me enough for some mustard..god..do you even have to ask why I love the women..trade in...never...absolutely never...hunny is that you..I'm coming dear...[p]LB

Angie2B

Lord Beasley,
That made me LOL. Thanks I needed that! -A2B

Steve-B

The Naked Whiz,
I knew you were up to something when you asked about the "laser-ray temp gun" thingy. You got that and a guru for fathers day...? [p]What other experiments do you have planned with your new toys. BTW...I'm jealous![p]Steve-B

TRex

The Naked Whiz,[p]Did you track the outside ceramic temperature throughout this cooldown period? It looks like there are two characteristic cooling curves here in each separate curve. The first cooling rate is faster, and is different for each test (a sharper slope for the Egg that didn't sit at 700 for long). The second cooling rate is much slower, and appears to be identical and independent of how long you leave the Egg at 700. It looks like your Egg will always reach this cooling rate, but the time at which it reaches this rate will depend on how long you had it sitting at the higher temperatures.[p]Here's some additional tests I'd be interested is seeing:[p]1) Same curves with a plot of outside ceramic temperature vs. time[p]2) Heat up curve showing outside ceramic temp vs. time once Egg is stabilized at 700 (how long will it take for the dome temp and outside cermamic temp to be the same, if ever - how close do they get to being the same?)[p]
3) Cooling curves similar to those above, but show the effect of having say the daisy wheel cracked open (bottom vent still closed).[p]Yeah, I could really dork out and have fun with this . . . lot's of interesting information that can be obtained.[p]TRex

Bob V

Great work! [p]I'd add to TRex's list the nagging question: what is the real difference between "dome" and "grill" temp, do they equalize over time, and - if so - at what rate?[p]Great charting - what did you use?[p]Bob V

Smoked Signals

The Naked Whiz,
As an engineer, I love experiments (and it seems you do as well). Charted data is even better. Can you do more? [p]What is the dome (1" below inside surface), grid, and shell temp during a cook. This would really give us some data to judge or estimate cooking temps. Especially how this changes when a load of cold meat is dumped into the egg. Something along the lines of a 8 or 9 lb pork butt? [p]It would be interesting to see when (time wise) the ceramic gets heat soaked (even all around). I seem to notice on low and slows that this takes about 1 or 2 hours. [p]I love experiments. I have a medium and might have to do some experimenting on my own.[p]Thanks for the data.
Doug

Unknown

Whiz, your way over my head man... are you a real scientist or something?

The Naked Whiz

TRex,
I have the cooling curves for the ceramic that go with the ones for the dome. The ceramic cooling was really relevant to the particular point that leaving the cooker at a high temp allows the ceramic to heat up, which then causes the dome temp to take a longer time to cool down. I'm working on a page that I do show the ceramic curve with the dome curve, but I'm not ready to post it yet. I've also thought about doing a test where you record the temps on heating up to see how the ceramic lags behind the air temp and where it levels off. But that isn't too important to understanding the "approach from below" technique. Anyway, we'll see what the future holds....
TNW

The Naked Whiz

Aack! I meant to say the ceramic cooling curve WASN'T really relevant to the topic of hot ceramic causing the cooler to take longer to cool down.[p]TNW

The Naked Whiz

Bob V,
The difference between grill and dome depends on lots of things like your setup. I was just considering the effect of hot ceramic on the cooling of the cooker. [p]The charting was just Excel.[p]TNW

The Naked Whiz

Chet,
No, just a scientist wannabe. Oh well.....
TNW

Unknown

Whiz, you might not be no scientist but your the next thing to one , cause I got a feeling your one jam up computer whiz. "did I say Whiz"?

TRex

Chet,[p]Haven't you ever seen Mr. Naked Whizzard's World on t.v.?

Charbon

The Naked Whiz,
Is it the 275 or 160 which is supposed to be child friendly? Most kids around here learn "Hot" when learning to crawl. Don't reach for the wood stove to steady yourself.