Trouble keeping temps up on my UDS

I just finished my UDS last week. I'm brand new to smoking. I have 3 1" holes about 2" from the bottom and 8 1/4" exhaust vents in the lid. I use ceramic magnets to cover the vents. My thermometer is just below the grill and is about 2" long. I've read that the outside of the barrel tends to be about 50 degrees cooler than the center but I have a 16" charcoal basket so I didn't think it would be that big of a difference.

I took it for a test run with no meat to season it (vegetable oil rubbed on the inside) and get a feel for temps. I did a hand test and didn't notice any difference in temp near the center and near the edge. During the test I kept all exhaust vents on the lid wide open. With one intake vent open the temperature held steady at 225 for 30 minutes. I to another vent off and it went up to 275 over the course of 15 minutes. Held steady there for 30 minutes before opening the last vent. Held steady at 350 until I closed all vents. Within 2 hours it was back down to room temperature. I was feeling pretty pumped. She held temp like a dream and was easy to control.

On Saturday I put 3 whole spatchcocked chickens on along with some brats as a last minute addition. I was aiming for 275 but even with all 3 vents wide open, it stayed at around 200. A few times during the cook I took the charcoal basket out and fanned the flames in an attempt to get the heat up. When I put it back in and closed the lid (without the meat) it would jump up to 250-300. As soon as I put the meat back on it dropped back down to 200. It took a lot longer but eventually the first chicken got to 165. I pulled it and the brats off. By the time the second bird was done about 30 minutes later, the temperature had risen to 250. When the 3rd bird was done it was up to 300. I shut it down and it was back down to room temp in a few hours. I imagine it would have gotten up to 350 if I let it keep running after I took all the meat off.

So what was going on? Do UDS generally run cooler with more meat on the grill? It can't be a ventilation issue. The gaps between the meat were significantly larger than my exhaust vents in the lid. Maybe the thermometer was too close to the meat giving it a lower reading than what the smoker was actually at? Any ideas? Anyone else notice this on their rigs?

Pics:
https://drive.google.com/folderview?id=0B756pS5Kcem7bFE5d2kyZTF4UkU&usp=sharing

PS: The food turned out great. Way more than 3 smallish families could have possibly eaten but that's what leftovers are for.

Fwismoker said:

Take and post pictures of your setup

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A link to the pics are located in the original post. I'll try to add them inline.

I measured and they are just shy of 1/2". I'll widen them up to 3/4", get some bigger magnets and report back after my smoke next week. Brats, hot links, and other assorted sausages.

smokeacholic said:

Have you got your fire basket sitting inside another drum? Looked like it in the photo. The meat had a big effect on the temp. Definitely needs more air.

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Nope. I only painted the top third of the barrel. Figured you wouldn't be able to see much below the grate anyway. Plus it will all be black from smoke and grease in a few cooks anyway. The fire basket is 16" x 8" hardware cloth (galvanization removed before cooking with it) woven together with some cheapo wire. It's raised off the bottom of the drum with 3" bolts. It's a temporary solution until I have the time to put together something nicer.

Kaptain Kadian said:

Did you paint the inside of the barrel?

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Just the top 3rd. I'm not worried about fumes. It was high heat resistant BBQ paint. I imagine I'd have to get over 1000F before it started melting off and messing with the food. It was just fine at 350F.

Cooked up some Brats and a Nekkid Fatty this weekend. Turned out great but I had the same temp problems as before. Couldn't get the thing above 225. I had all the air intakes and exhausts wide open. I even had the lid cracked open an inch. It finally hit 250 after about 3 hours. So it's not the exhaust and it's not being overloaded with meat.

The only other thing different from my first test run was the fuel. On the first run I loaded the basket about half full with lump. I took a small pile of lump (maybe 8" in diameter and 4" tall) and started it on my ghetto homemade charcoal chimney (Just some wire mesh and some bricks. My birthday is coming up so I'm not allowed to buy anything for myself. I'll be getting a real one soon enough) and waited for about 20 minutes until they were good and hot. Not fully ashed over but I didn't want to wait. I took that pile and dumped it on top of the basket, put the basket in the drum and closed the lid.

For the next cook I shook the loose ash out of the basket and filled it the rest of the way up with lump. I started it the same way as before with a small pile of lump.

This weekend I again shook out the loose ash but since I had used up my entire bag of lump I just took some from the basket that had hardly any ashing on it. Most of the chunks had some ashing but none were fully ashed over. Plenty of good fuel left in there.

So, is it that I'm reusing fuel? I've seen people on these forums talk about shutting down their UDS and then just topping off the fire basket for the next cook so I didn't think it would be a problem. I am shaking out the ash (there's not much with lump) so I don't think it's a problem of ash choking out the fire. I've seen people say they start their UDS with 10-15 briquettes of charcoal. Does it make a difference if you start with briquettes or lump? I'm stumped guys.

Lid cracked:


Stuck at 225:


Not so great view of the coals:



3 air intakes wide open:


8 exhausts wide open plus the lid cracked:


The fatty turned out pretty good. I cooked it to 180 internal but it was a little dry for me. I think I'll try 165 next time.