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March 13th, 2017, 8:09 pm
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Customer Service gets this question quite often, so I decided to redo the personal testing that I had done a few years ago, and document it so that you can make a more informed decision personally answering this question, and by all means, make your own decision(s), as that is one of the best parts of BBQ, you can decide on your own procedures when cooking.

The testing was done on a Yoder Smokers YS640 cooker with U29 firmware, with the 2 piece diffuser installed (door was in place), and the sliding damper handle pulled all the way out to the right. The pellets that were used for the test were a 50/50 blend of BBQR's Delight Pecan and Cherry.

The premise for this test is to show how the thermal dynamics of the cooker are affected by placing a pan, or a pan with water, in the cooker during a cooking session.

I used a ThermoWorks OctTemp ($1000) temperature data recorder, and 4 ThermoWorks thermocouples ($60 each), connected to a laptop running the ThermoWorks LogMaster software. I have placed a chart at the bottom of this, showing the temperatures for each probe and the milestone points that I will refer to throughout this post.


octtemp software.JPG

The 4 probes were attached in the center of the upper grate in the following way; 2 probes were mounted under the upper grate and 2 were mounted hanging over the upper grate. Probes 1 and 2 were below the upper grate, with probe 2 mounted 1 inch below the grate (where the meat will sit) and probe 1 is mounted 1 inch below probe 2. Probes 3 and 4 were mounted above the upper grate, with probe 3 mounted 1 inch above the meat placed on the upper grate, and probe 4 was mounted 1 inch above probe 3.

4 probe setup.JPG

To start, I cleaned the ash from the burn grate and firebox, plugged in the cooker, flipped the start switch to the ON position, and pushed the START button. I did not change the temperature from the default 350 degrees, as I want the metal mass of the cooker to heat up past the temperature I want to cook at.

default temp.JPG

After visually verifying that the fire had started, I closed the lid and walked away from the cooker for 30 minutes. After 30 minutes, I checked on the cooker and it was running maintenance mode at 354 degrees. I changed the set temperature to 250 degrees and walked away to get the meat ready to put on the cooker.

250 temp.JPG

Why use 250 degrees for the test? The majority of Yoder owners cook between 225 and 275 degrees, so I decided to use 250 degrees as a median temperature. No matter the cooking temperature, the effect and outcome will be pretty close to the same.

I wanted to approximate an owner cooking a brisket, so I used 2 beef chuck roasts of the approximate same size and cut 2" thick. I placed the roasts on a grate, to make placing them on the cooker easier, and pushed them tightly together so that they would approximate the size and shape of a brisket flat. I then placed the meat on the upper rack of the cooker, centering the meat with the probes (this is milestone #1 on the chart below). I then closed the lid and walked away for about an hour.

meat is on.JPG

meat is on 2.JPG

I wanted the meat to start to get warmed up and cooking before I added a variable to the test. Take a look at the chart from milestones #1 and #2, and remember that the set temperature on the cooker is 250 degrees. Notice what cold meat does to the temperature readings of the probes, and take note of the hottest through the coldest probe reading. Probe 1 and 4 are reading the hottest, and probe 2 and 3 are cooler. So the probes within an inch of the meat are reading cooler temperatures that the probes 2 inches away. Again, remember that the lower grate surface as displayed on the controller is approximately 250 degrees. This is why we always suggest placing probes a minimum of 6" away from any wall or anything cooking.

At milestone #2 on the chart below, I added in an empty aluminum restaurant pan, and centered it under the meat like a drip pan.

pan in the cooker.JPG

Take a look at the chart between milestone #2 and #3. Notice what placing the pan between the heat source (the surface of the lower grate) and the meat did to the temperature readings of the 4 probes. Now probes 1 and 2 are much cooler and probes 3 and 4 are hotter. But, the probes closest to the meat are still reading lower temperatures. Again, remember the cooker is set to 250 degrees.

After about an hour, I added approximately 1 1/2 gallons of 120 degree tap water to the pan. This is milestone #3 on the chart.

water in the pan.JPG

Oh no, what happened to the heat? The probes are still reading temperatures in the same way as before, but now they are much lower. Take a look at the area between milestones #3 and #4 on the chart, and remember that the cooker is still set to 250 degrees.

After about an hour, it was time to change the set temperature on the cooker to 350 degrees. This is milestone #4 on the chart. I did temp the water in the pan and it was 152 degrees.

default temp.JPG

Take a look at the area on the chart between milestones #4 and #5. The probes are still holding their places with temperature readings, even after the initial upper bump next to milestone #4, which was caused by the controller going into heat up mode. Notice that this is the first time that probes 1 and 2 go over the temperature of the boiling point of water in the pan (remember science class, water can never get hotter than it's boiling point temperature, so the closer the probe is to the water the less chance it has of reading a temperature over the boiling point of water), which is caused by the heat and air flow in the cooker rolling through the 2" space between the water pan the bottom of the lower grate, not because the water in the pan is boiling. Remember, the cooker is now set to 350 degrees. Do you think the water should be boiling at this point?

Time to crank up the heat again. Milestone #5 marks where I changed the cooker set temperature to 450 degrees. I read the water temperature in the pan at the time I raised the temperature, and it was 168 degrees. The meat temperature was 135 degrees.

450 temp.JPG

Examining the area on the chart between milestone #5 and #6 shows pretty much what we have seen so far, just higher temperatures being read by the probes. Remember, the cooker is set to 450 degrees.

Milestone #6 on the chart is where I read the temperature of the water (180 degrees, no boiling water for me) and shows what happens when I removed the water pan from the cooker. Notice that the probes all change places on the chart from the differing temperatures. This is illustrating the bottom up cooking that all the Yoder Smokers are designed to do.

Milestone #7 is where the meat hit my target internal temperature of 165 to 168 degrees. It didn't take long after removing the water pan to hit my desired temperature. Remember the cooker is set to 450 degrees. The meat went into the crock pot to finish. Pulled beef sandwiches for supper!

Now the interesting part, take a look at the area on the chart between milestones #7 and #8. I left the cooker running after removing the meat to show the differing temperature reading in the cooker empty and when something is cooking in it. This is why we always say to do our temperature test with the cooker empty, so we can verify the findings against a known baseline. Do our temperature test with something in the cooker, as you can see from the rest of the chart; there is no way we could ever match the results to a known baseline. Also, as a takeaway, all the testing in the world, on an empty cooker, means nothing after you put something in the cooker to cook, as EVERYTHING changes.

raw chart.jpg

I know you want to see what the meat looked like after I took it off the cooker. Well, I forgot to take a picture of the meat in the cooker. So you are going to have to be satisfied with a picture of it in the crockpot before I closed the lid.

165 internal.JPG

In answer to the questions I know you are thinking about; No the water pan did not "enhance" the meat in any way. If left alone long enough, the difference between the set temperature and the probe temperature reading would become closer together, but, with a pan, or water pan, it would take much longer to achieve a smaller difference. Yes, the test would have had some differing temperature reading if the meat was in pieces, i.e., turkey legs, as the air flow would not have been completely closed off as with the large, continuous piece of meat as in this test. I didn't put any pit probes in the cooker to verify the controller display temperature at the lower grate, as I know my cooker and trust it to do what it does best. If left long enough the water would most likely start to bubble at the higher temperatures.


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