DIY Heat deflector/fat diverter

scooter

Moderator
Staff member
One of the things I noticed on my first cook (chicken) on the drum was that cooking low/slow directly over hot coals with a fatty piece of meat over hours of time can result in a very heavy flavor overtone of what I call vaporized fat. I've read other posts that call it a "campfire" taste and have read comments on other forums about the same phenomena I experienced. People either hate it or love it.
I know BP, you said it's not the fat dripping on the coals but at this point I'm absolutely certain it is. It's the exact same taste I get when I grill over coals. Fat drips on coals, is vaporized then rises to flavor the meat only it's more muted when I grill. In my backyard grilling meats is done within 5 minutes whereas I cooked that chicken for over two hours over coals. More time over the fire, more fat drips down and vaporizes and ultimately I got a more intense fat flavor due to the extended amount of time over the fire.
Anyway, I set out to design something that will accomplish two things:

1) Divert most of the fat (but not all) away from the fire so I get a more subtle vaporization flavoring and keep that great direct cooking charm.
2) Deflect some of the heat away from the middle to the sides to lessen or remove the hotspot in the middle. More even heat across the entire cooking grate area.

This is what I came up with which I hope will accomplish both objectives. It cost me about $20 to fabricate. I cut, bent and welded everything in my garage. I borrowed an oxy/acetylene torch from a friend to do my welding. Watched some Youtube welding videos first to learn some of the basics of welding and safety. My welds are pretty ugly but should hold. Need more practice! I love welding now though! I hadn't touched a welding torch since metal shop in high school back in the mid 70's! Forgot how fun it was.
Tools I used: Bench vice, Sawzall with metal blade, drill gun, oxy/acetylene torch

Made it in two parts then assembled. A tripod base to sit in the upper Ubolts and the deflector/diverter that sits on top of the tripod. I think I may add another set of Ubolts about 3 or 4 inches further down the drum closer to the fire. I think it would function better being a little closer to the fire basket, but not too close. I don't want it so close that even the fat that gets caught in the channels vaporizes the same as the fat that makes it through to the coals below
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Assembled but the deflector/diverter is not welded to the tripod yet. I can rotate the deflector around to observe the effect in the cooker then I'll either weld it into the best position or just leave it unwelded so it will swivel when/if I need it to.
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It swivels for now but will probably get welded into place eventually.
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It's more centered right over the coal basket than this pic indicates and yes, I do foil the bottom of my drum. Did you expect anything else?? :)
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jimsbarbecue

Moderator
Staff member
Heat smoke diverter

Scooter I have used many kinds a 20 quart stainless bowl will work like a water pan in a WSM and solve your issue. I also have messed with a lot of diverters as I have metal yard close. The 20 quart pan will address what you looking into. To just help with hot spots I have different ways to address them, with the simplest I think the best. I will make another one and post pictures and measurements.
 

scooter

Moderator
Staff member
Patrick, not yet. Tomorrow I'll test it with another chicken.

Jim, I'm trying to avoid using a water pan. I already have a WSM. I got the UDS because part of its charm is it doesn't have a pan. I want the fat flavor just not so much that it's all I taste. So, my design lets some through, just not all.
 

scooter

Moderator
Staff member
Very happy! Tried a chicken last night using my design. The first chicken I cooked in the drum last weekend the fat flavor was all I could taste and could barely detect the rub and smoke. This time with my contraption in place, the fat flavor was nicely curtailed so I could also taste the smoke and the rub! Awesome. It also allowed enough direct heat through to carmelized the skin beautifully! So far the drum has made chicken look better than my MAK or WSM! I mean, it just looks soooo good! Now the balance in flavors is also there! I get smoke, rub and fat (which is the point of a drum smoker in my mind). My little deflector/diverter was a complete mess after the cook from all the crud it stopped from hitting the fire but the chicken came out beautifully!! Very, very happy with it!

Now for the hotspot data. Prelim temperature testing without my diverter showed a 60 degree difference from the center hotspot to the side of the drum. With the diverter in place the difference was reduced to a 20 degree difference from the center hotspot to the side of the drum. Will do more testing next weekend.
 
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jimsbarbecue

Moderator
Staff member
Chicken is so good on the drum. Nice that your diverter worked. 20 degrees is not bad as just the way the charcoal burns can lead to that. Try testing temps before you put food on and then after the food is off for comparison.
 

scooter

Moderator
Staff member
Yeah BP, my chicken will be done on the drum. Will be checking how tritip does next.

This is what didn't make it through to the fire from a single chicken.

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scooter

Moderator
Staff member
it was in balance with the rub and smoke instead of being so heavily forward that it was practically all I could taste in the last cook.
 

MrAdam

New member
Did you cook with the bird in the center of the drum before you tried the deflector, or did you try cooking the bird with indirect heat on the sides?
 

scooter

Moderator
Staff member
Both chickens were cooked in the middle right over the fire. I really hesitate to use my drum as an indirect cooker. I already own a WSM and if I wanted to do indirect cooking, I'd use the WSM. The whole charm of a drum, in my mind, was the semi direct cooking it does. That extra carmelization afforded meats that are cooked right over the fire. That's why I acquired this drum.
My first cook on it was a chicken which is a drippy, greasy mess on a cooker and it exposed an issue to me with drum cookers right away. When a fatty piece of meat is cooked over the fire for hours, with it comes hours of vaporized fat flavoring that can and will overpower all the other flavor components I added to the meat (ie rub & smoke). The flavor profile is knocked way out of balance in that all I could taste was the fat. I know it's not just me. I've read comments on this forum and other forums about this very thing.
The reason for my diverter/diflector was to try to mitigate the down sides of a drum smoker where I could have the best characteristics of the drum being the semi direct cooking without the drawback of the downsides being the overpowering flavor of fat over long cooks and a the hotspot in the middle.
So far, my deflector has performed great spreading the heat more evenly across the cooking surface, muting the fat flavor into balance with the rub & smoke and still achieving the external carmelization of the meat one would expect to receive from a drum smoker. This time I actually tasted chicken, rub (Money), apple smoke and the vaporized fat. A huge improvement over the last cook.
Looking forward to experimenting with each type of meat to see if it does better with or without the deflector. More updates are coming on that and will be performing more formal heat dispersion testing.
 
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Nafle

New member
well I don't have a smoker OR a WSM but I'm thinking of using it as both (with and without the pan it is :) ) I have a friend in south America that build his own drum smoker, made a heat deflector as a triangle. On top of that he places bricks to get an level temperature. so I'm thinking of Making one and drill some holes in it to get some dripping, BUT leaves me to able to place an bin of water. but I'll let you know.. I'll find an picture and post here.. :)

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scooter

Moderator
Staff member
Nice design. Should work great as a smoker. Is that access door above or below the deflector plate?
 
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