little help with the math...

MisterCode

So I've got 2 x 5.5lb Boston Butts. Once I get the Egg stabilized at X temp I'll only have 9hrs to smoke the butts to completion (internal temp of ~200).

What is X temp for 5.5lbs at 9hrs? 

MisterCode

I guess the normal 220 would be pretty close, right? 2hrs per pound... Maybe 250 then for 9hrs... Does anyone have a formula I could use to do this math myself?

I'd like to be able to ask the formula:

1) I've only got X hours (known time) to grill the butt. How much should the butt weigh (unknown weight) if I want to use the standard 220 EGG temp (known temp)? 

2) I've already got the butt (known weight) and I only have X hours (known time) to grill it. What does the EGG temp need to be (unknown temp)? 

Wow, I'm really getting into the weeds now. Sorry folks.

Fidel

There is no "math" - they all cook differently.  You can put two butts on with a very similar weight and one will finish hours before the other.  Too many variables involved.

That said, set your egg at 250 for the first 3-4 hours, then crank it up to 300.  If the butts don't get to about 180 or so with 3 hours to spare, then wrap them in foil and bump it again to 350.  They'll finish.

The most important step is to let them rest a minimum of 30 minutes before you go to pulling them.

MisterCode

Thanks Fidel. I take your advice. 

One question though on the 30 minute rest. I've always followed that rule. But the last one I did my guests were to hungry and they wanted to eat it immediately. It was getting a little late so I took it right from the Egg to the table. It was fantastic and everyone loved ripping off steaming chunks and eating it directly off the butt. Frankly, I was left wondering why it was so important to wait the 30 minutes. There didn't seem to be any ill effect. 

Fidel

The rest period allows the protein chains to relax and absorb some of the internal moisture (aka "juices").  If you cut into it, or start pulling it, immediately before it cools a bit then all that moisture and flavor runs out onto your carving platter.

It may not be as noticeable during the initial serving, but the portions you re-heat will be drier.