First UDS Pork Tenderloin- UDS Temp Control

[HOPTOAD]

Hi All,

I recently bulit my first UDS and have been smoking the past five weekends. We have done ribs, chicken, butts, fatties and yesterday tried out a pork tenderloin.

I started the UDS w a baseball size amount of lump in a charcoal chimney and added about 2 lbs of Royal Oak Lump to the charcoal ring. The lit charcoal on top of unlit. All charcoal used is Royal Oak Lump. I had the ball valve and one of the caps off the pipe nipple. Capped the pipe and closed the valve halfway once the temps hit 190. The Temperature slowly climbed to 210 and held for about an hour. Then the temps slowly began to rise. I wasnt concerned until they hit 240. Once it hit 240 I shut down all airflow thru the valve. The temperature still kept right on climbing up to 265 with all vents shut down. It stayed at or around 265 for about a hour. I left all vents capped until the temps dropped back to 230. Then I reopened the ball valve to just over halfway. Temps kept dropping so I opened it all the way. It held at 210 for about a hour then began to drop again. This time I removed a cap and shut the ball valve down to half. This allowed me to finish the smoke at a temp of 225 which it held for the next two hours.

How do you all keep the UDS at a rock steady temp? I have read that most are able to leave one cap off and the ball valve cracked open but I would think the temps would be greater than 250 using that method. I start out with all caps on and adjust using the ball valve at about halfway open. Doing it this way allows me to keep the temps about 220 for the fisrt few hours of the cook. I would think that if I took off one cap and cracked the ball valve it woul allow too much oxygen creating a fire that is to hot.

The tenderloin turned out great.. good smoke ring tender and juicy.

Here are some pics.





Thanks for the Advice
HOPTOAD

[N8man]

What diameter are your air intakes?
It appears you may have an air leak...
But, Lump Charcoal also burns hotter than Briqs
so it may be a combination....

[bigabyte]

Looks good! I'll let the UDS owners pitch in their thoughts on any troubleshooting. Just thought I'd comment on that tenderloin!

[joeysmac]

I built my first UDS a few months ago now and have recently changed the way that I get her going. I used to use 10-12 hot briquettes to get the charcoal started, but lately I have been having better success using 6-8 hot briquettes. Also, since there is already a certain amount of clean air in the drum, I start with all intakes closed, and after about 15-20 minutes I open up the ball valve about half way. If it looks like it's not getting enough air (the temp stops rising and plateaus at a lower temp), I open up the ball valve all the way. I've had much better control over my temps this way. I did an overnight butt this weekend (brethren-post soon to come) and the drum burned 3/4 basket of charcoal over 24 hours and rocked 225* about 95% of the time. It took about an hour or so for the temp to get where I wanted it, but it never spiked and got out of control...

Do you have any pics of your drum?

[HOPTOAD]

My intakes are 1 inch holes with 3/4 inch pipe nipples w caps. The pictures I have show the drum with magnets over the holes. I have replaced the magnets with pipe nipples and caps. I think it might have something to the combustion rates of lump v brickett charcoal.

Here are the pictures of the drum.

[HOPTOAD]

I have four 1 inch intakes with 3/4 inch pipe nipples with caps on three of them. The fourth has the ball valve. The 3/4 inch nipples fit tight in the 1 inch holes. You are right about the combustion rates.. the lump definalty burns hotter, that might be it.

The drum pics I have are from before I adeed the pipe nipples and ball valve. I was adjusting the airflow with magnets prior to the caps/ball valve.



Thank you for the compliments on the tenderloin and the help w the UDS.
HOPTOAD

[[email protected]]

Joey, do you use the briquettes to light lump or just briquettes?

[N8man]

I think if you light less lump next time and catch
your temp 10 degrees before your target temp
you may have better results. Let us know how this
plays out....

[joeysmac]

I used just briquettes this last time...have used a mix of briquettes and lump before, but felt like that was hard to control as well...I like grilling with lump and smoking with briquettes.

[BlueHowler]

I have used a mix of lump and briquettes for my last three cooks and I love it. 6 to 8 Briquettes to start the fire and monitor the temps on the way up and like N8man says 10º before your target temp is where you want to fine tune your air intake. I use magnets over my intake holes and can see exactly how much the holes are open and can adjust from there.

You would be surprised at the difference an intake hole only open 1/2 way verses 3/4 way open makes on the temp.

Your Tenderloin turned out great so I'd say don't sweat the small stuff and keep getting BBQ on the UDS experience so you can play your smoker like a Stradivarius violin.

[lionhrt]

From reading I have found every UDS is different I have found with mine I can control temp best using Blue K ( the only lump I can get around here is junk) and starting only 6 or 8 coals and only having the ball valve 3/4 open then let the temp rise slowly I ad my meat about 30 or 40 degrees low and then start closing the ball valve I can run a steady 225 with the ball vavle 1/4 open. You just need more practice and keep notes on each cook untill you master your USD.