newbie question - surface temperature vs. dome temperature

Short answer is, it does not matter, just be consistent.

Mosr recipies are dome.  Also, depending on time, during indirect cooks the dome and grate eventually equalize.

With that said, I use grate if its critical.

If you are running at 850 or above remove your thermometer all together.  Otherwise cal it afterwards.

I never use electronics for direct.  That is a sure fire way to ruin equipment.

Just pick one and ignore the other for indirect. As @Ozzie_Isaac said, most recipes are dome. On a long cook, they'll equalize. 

@ccoffey,

Pick one and cook by it consistently. I use dome for my cooks. 

I will, however, put a grate probe on (Maverick) for long low and slows just so I can monitor the temperature without running out to the Egg. I set the dome temp and note the probe temp. Usually, the Maverick and dome disagree at first, but will merge as the cook progresses. 

The placement of the grate probe can vary the reading widely - and this is why I don't use it. I calibrated my dome thermometer and I use it. It reads consistently every time.

Another point is to not worry about the temperature being off +/- 25 degrees or so with the coal heat. You will drive yourself nuts trying to dial it in exactly. Get it close, let it ride, and cook to the meat's internal temperature.

DoubleEgger said:

The crown prince of BBQ, Aaron Franklin, says to go by grate temp. 

Yes, but he doesn't use an egg. Different tools.

With practice, the dome therm is adequate in all set-ups, assuming it it calibrated. I tried using grill and probe therms early on, and all it did was give me an info overload. As you become used to vent settings, between familiarity w. the size of fire each produces, and having the point sample from the dome therm, you can be fairly sure of how the food is cooking.

Fussing over temp for most foods is not necessary. If you want precise control, SV will be the way to go except for searing or baking.

Here's a quick run down of the Eggs interior heat profile.

The lump produces hot air around 1000F, depending on how much carbon is in it. But, and this is really important, more energy is being produced as IR, enough to get objects near the lump up around 2000F.

The heated air rises, and at first, the dome area gets warmer than the middle of the Egg. As mentioned above, w. time, all the ceramics heat up, and the air temp within the column is fairly even.

The strength of the IR energy falls off by the inverse square. If the whole surface of the lump is glowing, the amount of energy at the gasket line is about half of what is present just above the lump, and the dome is getting about 1/4.

IF you place something under the food, such as a platesetter, the IR effects are stopped. Depending on the indirect device, the air above will vary. Initially, a platesetter will keep the air above it cooler than the dome. As it heats to above 600F, the heat air under the food will be hotter than the dome. IF a pan w. water is used for the indirect device, the vaporizing water will keep the bottom of the chamber relatively cool. But because moisture in the air makes heat transfer stronger, the lower temperature will cook more efficiently than dry air at the same temp.

Your temps were exactly what to expect with a setter in, dome is higher than grid. Without the setter it reverses, grid is higher than dome as the grid is closer to the IR of the lump. As noted above, do not use electronics when cooking direct it will shorten the probe life. If using eelectronics, it is also a good idea to run the probe wires over a setter leg to shelter from IR of lump. 

SmokingPiney said:

@ccoffey,

Pick one and cook by it consistently. I use dome for my cooks. 

I will, however, put a grate probe on (Maverick) for long low and slows just so I can monitor the temperature without running out to the Egg. I set the dome temp and note the probe temp. Usually, the Maverick and dome disagree at first, but will merge as the cook progresses. 

The placement of the grate probe can vary the reading widely - and this is why I don't use it. I calibrated my dome thermometer and I use it. It reads consistently every time.

Another point is to not worry about the temperature being off +/- 25 degrees or so with the coal heat. You will drive yourself nuts trying to dial it in exactly. Get it close, let it ride, and cook to the meat's internal temperature.

+1

DoubleEgger said:

jtcBoynton said:

DoubleEgger said:

The crown prince of BBQ, Aaron Franklin, says to go by grate temp. 

Yes, but he doesn't use an egg. Different tools.

Same principle though. 

Yep, it is the same principle.  And, Aaron makes that point in both his book and his videos.  He goes so far as to advocate moving the thermometer down to the grill level on inexpensive, store-bought smokers.

The saving grace with the egg is - for our low-n-slow, indirect cooks - a temp deviation of +/- 25 degrees doesn't matter ... thus, the advice to not chase temps.  Hell, we cook ribs anywhere from 200 to 375 degrees, so what's the big deal about a simple 25 degree deviation.  It just means the protein is done a little earlier or later than we planned.

Most times the dome temp is within 25 degrees of the grill level, so either will work.  Also note, that on a large egg, the dome probe is just a little over 5 inches above the felt line.  Since I usually position the pit probe an inch or two above the grill, they're almost at the same elevation.  But, having said that, I've also positioned two pit probes side-by-side and had one lag the other by 15 or so degrees for the entire cook.  Where you place the pit probe and how you shield it from IR and the flow of hot gases is critical to getting consistent results ... and yes, where you place it relative to the cold protein.  That goes for the dome thermometer also.  It needs to be shielded or it can start reading high if the fire moves to the front of the egg on a low-n-slow ... or read low if it's too close to the cold protein.

I like having both a dome and grill temp reading during low-n-slows.  The grill temp is primary, but the dome temp needs to stay within approximately 25 degrees of the pit.  If it gets too far off track, then the cook is not progressing normally and something needs attention.

The last point is that lump is organic and the egg is not high tech.  The fire moves around in the pit depending upon a handful of factors ... how big the lump pieces are, how they are stacked, air flow restrictions due to ash formation, etc..  The resultant airflow through the egg changes as the cook progresses and, combined with normal turbulence, creates a variable environment around the temp probes.

So, in conclusion, trying to get a consistent temperature reading is one of the reasons eggers drink so much.

Some old timer once posted a way to get the temperature down real quick when you've overshot. Put a pan of cold water on the grid and close the lid. I tried it last week and put ice cubes in the water, and it worked really fast.