New uds goes through charcoal too fast

[greg84]

That's weird part of, if it was leaking air, you'd have a hard time maintaining temperature and it would probably run hot. It doesn't sound like you have too much less charcoal than an 18" WSM, and those things will run at 250 for 12-15 hours if I'm not mistaken. Your basket appears to be of a conventional design, so I don't think that's your problem. What kind of charcoal are using? That will make difference. All I've ever used is hardwood lump, Royal Oak & Frontier mostly, but have run Cowboy was well, and have never had fuel problem. Are there any foils or ducts in the bottom that are changing (accelerating or funneling) the air flow? Have you talked with other users of your same smoker? Just some thoughts....

The charcoal I'm using is royal oak lump and I have 2 vents on the bottom that slide open or closed that came with the kit also. But nothing funneling or accelerating that I know of. And I tried talking with other people who have the same smoker, but none have responded. I did however talk to someone on reddit who has a different kind of drum smoker and he said that on his it only takes 3 hours for him to extinguish his charcoal after sealing it up. Because it takes mine hours and hours I figured its probably leaking, so for now my plan is to seal the leaks and go from there. Thanks

 

[Hamdrew]

Definitely possible, but you do have an aftermarket door, right? The stock ones are pretty bad. One of my WSM intakes is slightly bent and thus will never seal all the way. If you can't see by the naked eye, try shining a light on the other side of it in the dark.

Aluminum foil can do a pretty fine job at helping mitigate/eliminate that. Just crimp little squares over the intakes/exhaust.
[Also a good trick for light rain, making a little hood over the exhaust (I wrap it around the handle)]

 

[greg84]

Definitely possible, but you do have an aftermarket door, right? The stock ones are pretty bad. One of my WSM intakes is slightly bent and thus will never seal all the way. If you can't see by the naked eye, try shining a light on the other side of it in the dark.

Aluminum foil can do a pretty fine job at helping mitigate/eliminate that. Just crimp little squares over the intakes/exhaust.
[Also a good trick for light rain, making a little hood over the exhaust (I wrap it around the handle)]

No I dont have a door on my smoker. It's a drum smoker not a wsm. But using aluminum foil might do the trick. Thanks

 

[noboundaries]

I should also mention I've added a pizza pan heat deflector and stainless steel bowl water pan.

And yes I did have hot water in the pan. Maybe I'll try a test cook without the water pan and just the defuser next time just to see. Thanks

WATER is the problem. It is a heat sink, or a better way to say it, a heat sponge. It will absorb as much available heat as it can. The highest temperature water will reach is 212F, lower at higher elevations. If you are trying to run 225F, you're fighting physics. Even when the state of water turns to steam and expands 1700 times in volume, the steam will not exceed 212F at ambient pressures. Consequently, you have to burn a hotter fire, using more fuel, to maintain a 225F chamber temp.

No water next time like mentioned above. Your fuel will last MUCH longer.

 

[BandCollector]

oh i figured, i just meant to ask whether you've tried other "minions", and if how does that "S" compare to those other minion methods (like putting lit coals in the center, or snaking coals around the outside of the charcoal basket).

i like the flavor profile of fat dripping directly on the coals, but am curious.

Most Minion Meathods work just fine. I came up with this one and found it to be the most controllable for temperature control and usage of charcoal in my UDS.

John

 

[bill1]

Make one of these and use the Minion Method...John

Nice work John! Are those curved clay roofing tiles for the labyrinth? How did you cut and drill them?

 

[bill1]

To the OP, Greg84: maybe you're just burning your fuel too fast? How much temp do you lose if you throttle back your air intakes a bit? If it's too much, maybe just reduce the heat you lose out the sides by sliding a big box over it? (A lot of Big Poppas don't have side pipes and draw air strictly from the bottom so then you'll want to space the box up off the ground on a few bricks.) The big box also greatly reduces the effect that breezes have at cooling down your cooker...which then require more fuel for a given cook temp.

 

[greg84]

To the OP, Greg84: maybe you're just burning your fuel too fast? How much temp do you lose if you throttle back your air intakes a bit? If it's too much, maybe just reduce the heat you lose out the sides by sliding a big box over it? (A lot of Big Poppas don't have side pipes and draw air strictly from the bottom so then you'll want to space the box up off the ground on a few bricks.) The big box also greatly reduces the effect that breezes have at cooling down your cooker...which then require more fuel for a given cook temp.

My big poppa vents have a slide which slides over four 3/4 inch holes on each side. I'm only leaving a half hole on each side open in order to maintain 225 to 250. I haven't tried dialing back any more as I reached the temp I wanted, so I just left it alone.

As for the box, its something to consider, but for now I'm going to focus on fixing the leaking lid and see if that makes a big difference. I suspect it will.

You mentioned loosing heat out the sides. Do you mean through the metal drum, or though some type of leak? Thanks for your help

 

[greg84]

WATER is the problem. It is a heat sink, or a better way to say it, a heat sponge. It will absorb as much available heat as it can. The highest temperature water will reach is 212F, lower at higher elevations. If you are trying to run 225F, you're fighting physics. Even when the state of water turns to steam and expands 1700 times in volume, the steam will not exceed 212F at ambient pressures. Consequently, you have to burn a hotter fire, using more fuel, to maintain a 225F chamber temp.

No water next time like mentioned above. Your fuel will last MUCH longer.

Yeah between that and the leaking lid I think I'll get it sorted, but we'll see. Thanks for your reply

 

[BandCollector]

Nice work John! Are those curved clay roofing tiles for the labyrinth? How did you cut and drill them?

bill1

Yes they are clay roof tiles.

I cut them with a 10" masonry blade in my chopsaw. Cut them easily and beautifully.

Drilled them with a masonry drill bit and bolted them together.

John

 

[Workaholic]

Definitely take a look at those leaks. Something else you may want to look at, is to run the intakes like it's a WSM. Use only one intake, unless you are having trouble maintaining temps with 1 intake all the way open.

An example: on my 22.5 WSM, which is approximately the same size as your Big Poppa, once I'm up to temp, I have the exhaust all the way open and am using one intake to control temps. I start it with all 3 open, and slowly close down two of them as I near cooking temp.

I am wondering if you having both intakes partially open is causing enough of a cross draft to have more charcoal burning than needed. Most of the people I know that run a version of the uds, including the big poppa, will have 3-4 intakes on the cooker, but only use one after up to temp

 

[apn73]

Definitely take a look at those leaks. Something else you may want to look at, is to run the intakes lime it's a WSM. Use only one intake, unless you are having trouble maintaining temps with 1 intake all the way open.

An example: on my 22.5 WSM, which is approximately the same size as your Big Poppa, once I'm up to temp, I have the exhaust all the way open and am using one intake to control temps. I start it with all 3 open, and slowly close down two of them as I near cooking temp.

I am wondering if you having both intakes partially open is causing enough of a cross draft to have more charcoal burning than needed. Most of the people I know that run a version of the uds, including the big poppa, will have 3-4 intakes on the cooker, but only use one after up to temp

I agree with this. I control my UDS by leaving the exhaust, the damper of the 22" kettle lid, wide open and I'm maintaining 250 degrees through a single 3/4" hole. That hole is partially blocked by a rare earth magnet, so that's not much air to keep it going

 

[apn73]

WATER is the problem. It is a heat sink, or a better way to say it, a heat sponge. It will absorb as much available heat as it can. The highest temperature water will reach is 212F, lower at higher elevations. If you are trying to run 225F, you're fighting physics. Even when the state of water turns to steam and expands 1700 times in volume, the steam will not exceed 212F at ambient pressures. Consequently, you have to burn a hotter fire, using more fuel, to maintain a 225F chamber temp.

No water next time like mentioned above. Your fuel will last MUCH longer.

My story in a previous post about smoking a Boston butt for 17 hours, a water pan was the reason why. Some of the barbecue cook books that I own advocate for the use of a water pan to keep things moist. Maybe they work just fine in other types of smokers, but water pan bad in a UDS. I tried it once and I'll never use water again, at least not in a UDS.

 

[apn73]

Most Minion Meathods work just fine. I came up with this one and found it to be the most controllable for temperature control and usage of charcoal in my UDS.
View attachment 497945


John

That's good looking Ugly there BandCollector, what did you use for the top ring in the picture? Where the cover goes? Thanks!

 

[BandCollector]

That's good looking Ugly there BandCollector, what did you use for the top ring in the picture? Where the cover goes? Thanks!

The top ring was cut from the bottom half of a Weber Kettle. I cut off the top 3 inches and bolted it to the top of my drum.

John

 

[apn73]

The top ring was cut from the bottom half of a Weber Kettle. I cut off the top 3 inches and bolted it to the top of my drum.

John
[/QUOTE

The top ring was cut from the bottom half of a Weber Kettle. I cut off the top 3 inches and bolted it to the top of my drum.

John

Okay, that's a good idea. I actually took a 4" grinder and ground around the lip of the drum until the kettle lid fit. It's worked out okay, haven't had any problems.

 

[bill1]

Just to quantify water pans a bit...

• Water's specific heat is 1 calorie per gram per degreeC of heat rise. So for liquid water to go from room temp (30C) to boiling (100C) is 70 cals/g.
• The heat of vaporization of water is large...540 calories per gram. That turns water at 100C to steam at 100C.
• The specific heat of steam is ~.5 cals/g-deg. So to go from 212F to 250F (38F or 20C) is 10 cals/g

Add them together and each gram of water takes 620 cals to get to smoker temp.
By comparison, charcoal's energy content is ~12kcal/g or 12000 calories per gram.
So a pan of water "wastes" about a half pan of charcoal.
In a bullet smoker like WSM, there's typically a door to add more fuel and add more water. But not in a UDS. It wouldn't be hard to rig a feed to a water pan and even keep it at a constant level but that's a very uncommon mod. Which isn't unsurprising since it doesn't sound like the UDS folks care much for water pans.

But I don't think the OP's use of a water pan is a full explanation for why he's using a lot of charcoal.

 

[greg84]

Just to quantify water pans a bit...

• Water's specific heat is 1 calorie per gram per degreeC of heat rise. So for liquid water to go from room temp (30C) to boiling (100C) is 70 cals/g.
• The heat of vaporization of water is large...540 calories per gram. That turns water at 100C to steam at 100C.
• The specific heat of steam is ~.5 cals/g-deg. So to go from 212F to 250F (38F or 20C) is 10 cals/g

Add them together and each gram of water takes 620 cals to get to smoker temp.
By comparison, charcoal's energy content is ~12kcal/g or 12000 calories per gram.
So a pan of water "wastes" about a half pan of charcoal.
In a bullet smoker like WSM, there's typically a door to add more fuel and add more water. But not in a UDS. It wouldn't be hard to rig a feed to a water pan and even keep it at a constant level but that's a very uncommon mod. Which isn't unsurprising since it doesn't sound like the UDS folks care much for water pans.

But I don't think the OP's use of a water pan is a full explanation for why he's using a lot of charcoal.

Well I cant say I understood all of that, but I do get the idea, so thanks for that. And yeah I agree the water pan is hurting, but I dont think its the whole story. Which is why I think I should focus on the leaks first. Then I'll take a look at bill1 mentioned, and see how much I can dial back the vents.