UDS Diffuser Throwdown

[---k---]

I've done about a 1/2 dozen smokes on my UDS now. The last smoke I did was a Turkey. With the higher temp (~325*) and I really noticed the difference between the center temp and the edge temp. So, I got interested in trying out a diffuser. Today, it is a wonderful 30* outside, so what better time.

This isn't a perfect test. As with all first attempts, I had some issues, and everything didn't go as planned, but I just rolled with it and think I got some usable results.

I lit a little more charcoal than normal, and spread it around to get more even heat diffusion.

The contestants:
Test 1 - No Diffuser
Test 2 - ECB Waterpan, 13.5" dia, 4" high w/ water.
Test 3 - Bunt Pan, 10" dia, 3.5" high w/ water
Test 4 - Pizza Stone, 15" dia

The temps are being measured with a thermometer on the side and my maverick wired to the bottom of the grate.

I'll also be measuring temps using these:

Test #1
Start 12:50.
Outside temp = 325*
Middle Temp = HHH - greater than 450*??? Wow
Cook time = 10 mins.

Test 4 is about to come off the smoke now. So, I'll post updates later.

 

[---k---]

Crap. My photos didn't show up. Google's picasa doesn't allow this. Must use photobucket... I'll fix after the last rolls come off.

 

[swamprb]

Blasphemers!!

 

[---k---]

Drum Temp and Cook time varies. You can not compare tests to each other.

Test #2, ECB Water Pan
I filled the water pan with hot tap water and let it simmer in the drum for 30 minutes. The drum wanted to run about 300* on the side with all vents open, so that's how we rolled.

Start 12:30 pm
Side Temp = 300*
Middle Temp - 258* after 5 mins.
Cook Time = 25 mins

Outside edge obviously a little hotter, but a more uniform cook than no diffuser.

 

[---k---]

Test #3 - Bunt Pan

Like the ECB pan, I filled it with hot tap water and let it cook for 30 mins prior to loading the drum.

Start 2:30 pm
Outside Temp = 310*
Middle Temp = 322* after 5 minutes
Cook time 25 mins

I could see differences between this and the ECB pan. There definitely was small hot spot in the middle, and a hot spot around the edge.

 

[Johnny_Crunch]

awesome comparison! Thank you!

 

[Dave Russell]

The only diffuser I've used was an ECB charcoal pan, foiled to leave an air gap, and I typically used it for spares or chicken if cooking more than one rack's worth. On my new drum though, I'll probably try using it for butts or briskets as well. Gonna use a LOT more charcoal, though.

 

[---k---]

Test # 4 - 15" Pizza Stone

I didn't realize how much charcoal I was going to use. So, before this test I had to pull the firebasket out and re-fill it and light another chimney. Of course I spilled most of the ash in the drum in the process... and I think I was a bit impatient with the charcoal in the chimney, because it took a while to get the drum back up to 300*. The stone was in there for a good 20 - 30 minutes to get preheated.

Start 4:25 pm
Outside temp = 290*
Outside temp = 295* after 25 minutes
Middle temp = 265* after 5 minutes
Middle temp = 306 after 25 minutes
Cook time = 30 minutes

This one seemed to be the most even. But, the outside was still a little darker.



I think I like the pizza stone or ECB pan. There will have to be more testing. I think the weather will make a difference. I saw the side temp drop pretty dramatically every time I opened the lid. Much more so than when it was warm outside. I'm not sure my temp probe in the middle was as accurate as it could have been, because it was wired tight to the mesh grate.

 

[---k---]

After all that work, time to make dinner

The plan is to use the remaining package of rolls and some eggs for some Croissanwiches.

 

[Dave Russell]

Ryan, maybe I'm missing something, but are you sure you want all that grease falling on a pizza stone?

The ECB pan works great if you foil it w/ an air gap, and if you can find something the same size or a bit larger w/out a rim, so much the better.

 

[Rich Parker]

Terracotta pot base lined with aluminum foil works great. You get them in any size you need.

 

[bigabyte]

I put a little sand in my ECB pan for my WSM's, and cover that with foil. An air gap may be just as effective, I've never compared the difference.

 

[BRBBQ]

I bought an 18" pizza pan for $3, I like the diffusser in but I need to get a deep dish one for more water:becky:

 

[---k---]

Ryan, maybe I'm missing something, but are you sure you want all that grease falling on a pizza stone?

The ECB pan works great if you foil it w/ an air gap, and if you can find something the same size or a bit larger w/out a rim, so much the better.

Dave,
You're not missing anything. I didn't really think about grease falling on my pizza stone. I knew a lot of people use terra cotta pots, as Rich mentions, I figured a pizza stone was similar and threw this in the mix because I had one.

I keep looking at the results and am thinking I like the ECB the best. I think Webber might know what they're doing! :wink:

Why do you you suggest a pan without a rim? I can probably find a metal mixing bowel without a rim. Just not sure if it is worth it.

Right now, I'm thinking either a sand filled bowel or a terra cotta pot, one of the big diameter but shallow ones.

 

[Dave Russell]

Dave,
You're not missing anything. I didn't really think about grease falling on my pizza stone. I knew a lot of people use terra cotta pots, as Rich mentions, I figured a pizza stone was similar and threw this in the mix because I had one.

I keep looking at the results and am thinking I like the ECB the best. I think Webber might know what they're doing! :wink:

Why do you you suggest a pan without a rim? I can probably find a metal mixing bowel without a rim. Just not sure if it is worth it.

Right now, I'm thinking either a sand filled bowel or a terra cotta pot, one of the big diameter but shallow ones.

Yeah, Weber most definately knows a bit about smokers and grills, but speaking of pans, it's funny how they went from the shallow pan (Smokey Joe lid) to the great big pan (Smokey Joe bowl) that doesn't allow much room for tending the fire or heaping coals.

The ECB pan is what I use in my wsm, whether it has water or foil, but when I mentioned the rim, I was thinking about how it's wide enough for some of the fat to burn on it, not a good thing if cooking a turkey over it, for example, as I found out on Thanksgiving. I guess I should've layered it up a good bit, or just put a drip pan on the bottom rack. Turkey fat is not something you want smoldering, and I know it's not much of an area for it to land on, but it sure did stink.

 

[big brother smoke]

Nice research!

 

[jasonalan724]

i use an 18 inch pizza pan with about 17 1 inch holes drilled in a symetric pattern it seems to spread the heat around pretty well, as well as agitate the smoke

 

[swamprb]

Nice job on your smoker log info.
While I don't care to use a deflector or waterpan in my drums, I realize there are those that don't care for the direct cooking and dripping fats on the coals flavoring their meats, so this should be helpful to them.

I do use foiled over pizza stones in the waterpans of my WSM's and Cajun Bandits.

One thing I might suggest is to go to a restaurant supply and get a stainless mixing bowl about @20" dia. for the 55 gallon drums. I got mine at Cash n' Carry for $24 and it fits my 22" WSM and Cajun Bandit and if I were ever to use a deflector in my drums it would be my choice.

JMO

 

[---k---]

Nice job on your smoker log info.
While I don't care to use a deflector or waterpan in my drums, I realize there are those that don't care for the direct cooking and dripping fats on the coals flavoring their meats, so this should be helpful to them.

I do use foiled over pizza stones in the waterpans of my WSM's and Cajun Bandits.

One thing I might suggest is to go to a restaurant supply and get a stainless mixing bowl about @20" dia. for the 55 gallon drums. I got mine at Cash n' Carry for $24 and it fits my 22" WSM and Cajun Bandit and if I were ever to use a deflector in my drums it would be my choice.

JMO

So you have a Drum and a WSM? One direct and one indirect. Do you have a preference. I have a drum and ECB. I haven't done enough smokes to know which taste I prefer - I'm leaning towards no fat drippings. I've just had such wild temperature differences between the edge of my drum and what my maverick reads at the middle. And, it varies, one day it is the same, then next it is 40*. And sometimes it varies throughout the cook. I haven't found the consistency yet. I'm hoping that some type of diffuser will get me there.

I'll probably end up with the mixing bowl. I measured one there the other day that was ~20". I might pick one of those up and also a couple smaller to try out. Then fill with sand.

I think a pizza pan with holes drilled would work well. Someone has posted a very cool [late that was CNC w/ varying sized rings. It looks like it would even out the heat really well. But I think I want something to catch the fat.

I actually started this thinking that I was smarter than Webber, et. al. and that the bundt pan was going to be the winner. I mean, if a UDS is hot in the middle and cold around the outside, and a WSM is hot at the edge and cold in the middle; then a bundt pan had to be the winner! I was hoping the air coming through the middle would spread out and merge with the edge. Didn't quite work out that way. It was just to small in diameter and gave me a hot spot to the edge. If I could find a 20" dia bundt pan, that might be a great test. But, I went through two restaurant supply stores last week, and neither had them.

 

[jestridge]

Just wondering What about a pan full of lava rock or a pan of those cermic bbq bricks