Hot Chamber But Raw Butt

[diygoodeatin]

New to BBQ and new to this forum - In need of some good advice.

I've built a brick offset smoker, followed all the calculations on vents/exhausts and chamber sizes and was chuffed when I set it away on a trial run and after an 45-1hr (in cold windy conditions) got my smoking chamber up to 225-235 def F and holding steady.

I put a medium pork shoulder on (butt cut not so easy to get hold of in the UK) after rubbing and fridging it over night and I'd taken it out an hr or so before to come up to room temp and added some apple wood for smoke.

I have an Ivation wireless thermometer with smoker temp probe and meat probe, so I inserted the meat probe and shut the door.

Smoker went straight back up to the 225-235 deg F and the meat was at around 45 deg F.

Every hr or so I added a few pre lite coals and the temp remained steady - again, I was chuffed!

This is where the problems started. 3 Hrs later, smoker temp steady, my internal meat temp was only 90 def F. 4Hrs, it was at 88 deg F.

I repositioned the probe in the meat and checked the smoker probe was close to the meat - it was was. I checked I was reading in Deg F, not Deg C and I was.

8 Hrs later and the meat still at 88 Deg F, I abandoned the smoker and put the meat in the oven at around 290 Deg F for 4 Hrs. As soon as it went into the oven, the internal temp started to rise and It ended up at 190 - at which point I turned off the oven and went to bed!

How is this possible? The smoker temp probe was never more than 6 inches away from the meat!

Any help or suggestions would be appreciated!

 

[dirtsailor2003]

Did you test your therms probes prior to the smoke? Do boil rest to make sure they are accurate. 212f is what they should read or close to it.

I've had 8# butts take upwards of 20 hours running my smoker at 250-265.

 

[diygoodeatin]

Thanks for the reply. I didn't test them before, but they seemed to match my oven temps when I movedthem inside. I 'll follow your advice and test them tonight. Cheers.

 

[cliffcarter]

You may have had the temp probe too close to the bone, if UK butts have a blade bone. BTW I never insert a probe into the meat until it has been on the pit for 5-6 hours, there really is no need to do it before then IMHO.

 

[diygoodeatin]

Cheers for the reply. This one didn't have a bone in as I was just really testing. I guess I just had the probe in so early out of interest.

I'm going to get a second thermometer and double check the smoke chambers temp tonight.

 

[daveomak]

Does your smoker operate with good air flow..... Fair amount or air in , air out while cooking.... Sounds like you have low air flow in the smoker and you are measuring IR temp radiating from the brick.......

Dave

 

[diygoodeatin]

Not 100% certain of what you mean but I 'll be googling it more than I already have l this evening. Does it matter what heat source I'm measuring, so long as it's heating and reaching a temp of 225-260? I will recheck my airflow calcs. I've currently got a smoke chamber / firebox that has a 6 square inch inlet and a chimney that is 54 inches long with a 2 inch diameter.... Cheers Dave.

 

[daveomak]

Air flow..... I'm referring to the amount of heat/smoke/air moving through the cooking chamber.... You need a bunch.... A cold hunk of meat in the smoker has a zone of cold air around it.... the air is cooled from the cold meat..... If you do not have a good movement of heated air around the hunk of meat, it will not heat up... Air has little thermal mass..... meat has a lot of thermal mass..... You need to transfer the heat from the air to the meat in order for it to cook......

Hope that makes sense..... think of how a convection oven operates and cooks meat FASTER because of the increased air flow.... Physics... simply physics..... just like how much colder it feels when you are outside at 20 degrees.... 0 mph wind... and 30 mph wind... that's wind chill ..... we need the opposite when cooking..

Dave

 

[diygoodeatin]

Excellent, makes total sense. Thanks Dave. I 'll have to experiment with both, I've a feeling my outlet may be too small/restricted. When it's sorted, I'll let you know. Cheers.

 

[cliffcarter]

Another thing that you may want to consider is that you did not pre-heat the pit long enough and/or at high enough temp to heat up that mass of brick before you put the meat in. The brick may have been still storing thermal energy when you put the meat in, thus keeping the meat cool. I suspect 45-60 minutes is not long enough to get the mass of brick up to a high enough temp to stop sucking the heat out of the cook chamber.

How did you start your fire and how big was it initially? I think that if you start a big wood fire in the fire box and feed it for a couple of hours you may solve the problem.JM2C.

 

[diygoodeatin]

Ah, interesting Cliff.....My brick walls are about 10 inches thick so, yes, I guess it would absorb a lot of heat... That was my thinking in making them so thick as it would retain the heat and make the process of keeping an even temp over many hrs... Or at least that was my thinking.

Okay, moving forward, I'm going to increase my exhaust outlet size to increase the draft and also get the pit up to temp and held steady for longer to ensure its all pre heated.

I 'll post my results later in the week!

Thanks for all the advise

 

[daveomak]

Good point Cliff..... 10" thick brick could take up to 24 hours to get up to a stable temp.....

 

[diygoodeatin]

24hrs.... Ah, perhaps I should have contacted you chaps before I built it!

Nevermind, I 'll crack on! Thanks again.

 

[daveomak]

I built a block smoker that took at least a day to warm up.. probably a rick of wood..... That build was a mistake..... too darn expensive to run....

 

[shane m]

You could always bring the cc temp up using a gas burner. This would also increase the draft as you start your fire. I worked at a meat processor, and our smokehouse was big enough to accommodate 2000 pounds of linked sausage. We used a propane burner for a manageable heat, and built a wood fire in a metal box and pulled it in the smokehouse when it was ready. This method works great, but some purists are completely against using any gas...... I am more into the final result