Problems with Temperature control in UDS

[Dr. Endo]

Hi guys, I'm new to the smoking world, but very motivated. I just finished making a UDS. I think it looks pretty good. I'm using a Weber lid because I couldn't find a barrel with a lid. It was a half inch small so I bent the flange out so that I could fit it to the barrel better. It still leaks a little but since I can control the flow with the vent control on the lid I didn't think that it would be much of a problem. I have smoked a couple of items so far with reasonable success. My problem lies in temperature control and more specifically initial temperature rise. I have only been smoking things for about 4-5 hours. To do this I put aprox. 5 lbs lump charcoal in with 3 fist sized pieces of hickory. It takes an hour just to get to 220 with three 3/4 inch vents open and my ball valve completely open. Then to maintain the temperature I leave the three vents completely open. I'm going to try and smoke a butt for 12-14 hours this weekend using 8.5-9 lbs lump charcoal. I don't think that it's going to make it. On other peoples blogs I read that they get the temp up pretty fast and then close off most of the air vents to bring it down and slowly cook that way. What am I doing differently? Any advice or mods that you all could suggest?

[N8man]

Allow me to share with you a little
something I wrote up a while back....I hope this helps...

http://www.bbq-brethren.com/forum/sh...70&postcount=1

[huskerfan1200]

How much lit charcoal do you start with? For my UDS, it heats up pretty quick using 1/3 to 1/2 chimney of lit coals.

[AlanTX]

Make sure that your charcoal basket is located ABOVE(higher) than the intake holes so that there is adequate air flow to the fuel. Maybe you should light up more coals at the start. I have no clue of what your charcoal basket capacity is, but if you're going to smoke a butt and see it taking 12-14 hours, you are going to have to fill that baby up; I don't believe 5# is going to make it for that duration.

[kevine]

Originally Posted by huskerfan1200

How much lit charcoal do you start with? For my UDS, it heats up pretty quick using 1/3 to 1/2 chimney of lit coals.

I used about a third also. Heats up quick, and then I start closing off vents until I only have one open which keeps it about 230-240

[ROF, Texas]

N8man,
Thank you for this informative thread. I completed my UDS build a few weeks ago, followed your information and all has worked perfectly. The second time I used the drum I did a 16 hour cook for brisket and chicken and all was good!

Thanks Again

[Dr. Endo]

Thanks guys for your speedy replies. that is a nice thread N8man. I'll try and add some more charcoal and raise my basket. I have some thoughts on what could be causing my troubles. My weber lid leaks too, and that might not be good. I have an idea of making a lid from wood. I'm sure that it wouldn't catch fire and I think it might look pretty cool. I'll rub it down with some mineral oil first. At least I know that I could make it fit perfectly.

[---k---]

Big Mista or Big Brother Smoker posted once about using flat piece of plywood for a lid. Worked for him without any crazy rub down. Maybe someone can find it.

I find it slightly odd that you have to keep all three bottom vents open to sustain temps. That is odd. In this case, I don't worry too much about a slightly leaky lid. Usually the leaks are more a problem with keeping temps down. It might have more to do with not lighting enough charcoal at the start.

[The Frog]

I generally keep 2-3 vents open on mine. My vents are 3/4" nipples, so perhaps that is the reason.

Dr. Endo,

It sounds like you've got a handle on it, but if you have good airflow around your basket, your drum is sealed, and your basket is large enough, you should be able to go 14-24 hours with a UDS at a very steady temp (225-250 in my case). I have, however, had better luck with certain fuels. For long burns, I have had the best results with a good charcoal. Now I haven't tried all the brands, but the Kingsford competition briquettes seem to give me very stable temps, little ash, and burn forever. My experience has been that lump, as much as I like it, is not as consistent.

Like N8man said in his tutorial, there is no wasted fuel in a UDS (as long as it is sealed), so load that thing up. I'll put 20 lbs in mine, just shut it off when done.... burn the rest next time.

[WvSmoke]

Originally Posted by ---k---

I find it slightly odd that you have to keep all three bottom vents open to sustain temps. That is odd. In this case, I don't worry too much about a slightly leaky lid. Usually the leaks are more a problem with keeping temps down. It might have more to do with not lighting enough charcoal at the start.

+1^^^on the leaky lid. Sounds more like a fire basket/air flow problem. Can you post some pics of your setup?

[dae06]

My first burn on my UDS was yesterday. It went 12 hours on 3/4 bag of lump. I had to wait for the temp to drop to 240 right away. I had only 1/2 of a 3/4" vent open most of he time. Sounds like intakes or air flow to the coals could be the problem. I think I could get to 500 degrees in mine if I wanted to.

[retired trucker]

You said you had 3/4 in intakes. Did you drill 3/4 in holes in the drum and then put pipe nipples in the holes? To get 3/4 in pipe nipples in the holes in your drum, you would have had to drill one inch holes. Are you using 1/2 nipples. This may be why you can't get enough air to get your temps up.

[PorkQPine]

I know i't only a UDS but I can tell you that having a draft controller is a big plus. I got mine from Auber instruments and it works great. I use lump because it does not leave much ash in the longer cooks so it does not choke out the fire. I use a charcoal chimney and put in enough lump to get about 1/3 full. When it is nice and going I drop it on the lump in the firebox, add a few chunks of wood and close the lid while the Auber does it's magic. When temp is where I want it I put on the food, close the lid and wait until it's done. All top vents are open and it is nice to not worry about temps during the night when doing the long meats since it will run over 12 hours at least without doing anything.

[huskerfan1200]

Originally Posted by dae06

My first burn on my UDS was yesterday. It went 12 hours on 3/4 bag of lump. I had to wait for the temp to drop to 240 right away. I had only 1/2 of a 3/4" vent open most of he time. Sounds like intakes or air flow to the coals could be the problem. I think I could get to 500 degrees in mine if I wanted to.

About how many pounds of lump was that? What kind? Is the bottom of your charcoal basket above the level of the intakes?

It was a pretty nice day around here yesterday with little to no wind. Having one vent open only 1/2 way sounds about right for a temp of 240. Mine will do 225 on half a vent with no wind and warm ambient temps.

[dae06]

Originally Posted by huskerfan1200

About how many pounds of lump was that? What kind? Is the bottom of your charcoal basket above the level of the intakes?

It was a pretty nice day around here yesterday with little to no wind. Having one vent open only 1/2 way sounds about right for a temp of 240. Mine will do 225 on half a vent with no wind and warm ambient temps.

It looks it a full bag has 8.8 lbs., so I guess I used 6-7 pounds. Here is the stuff I use from Menards up here in the Midwest. I am thinking about trying Stubb's from Lowes. No reason, just that I have heard a lot of good things regarding it. I am very happy with my Menards Lump though.

Lump from Menards

Just noticed your location. You know where Menards is :). My first cook was Monday. Really windy!!!!