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Fellow 'quers,

"It's done when it's done". While truer words were never spoken, sometimes the fast pace of life can get in the way of your 'que planning. While I'm not opposed to eating a few hours early or late every once in a while, I just can't deal with it when guests are invited.

I'd like to gather some data from as many people as possible in order to come up with a regression equation that estimates butt cook time...I'll run it through my stats PhD woman-friend and be able to tell you how accurate it is.

Interested? To contribute, let me know the following for as many butts as you have data available:

1) Butt weight
2) Temp you set the smoker
3) Outside Temp
4) Internal temp you cooked to
5) How many times did you open the door? (you know you've done it before!)
6) How long did you let the butt sit at room temp before putting in the smoker?
7) Did you preheat the smoker?
8) Type of smoker
9) How long did it take?
*if you do the same things each time, feel free to consolidate if you have data from multiple butts*

I know this is a pain, but if we can get an equation that is accurate within half an hour or so across a broad range of variables, it would be a great tool!

I'll start it off:
5.05lb butt, set to 250, 75 outside, cooked to 176, opened the door 3 times (remote thermometer was broken!), 30 minutes at room temp, no preheat, smokette, took 11 hrs.

We probably need 50-75 butts worth of data to make this work - if everyone gives data for one or 2, it will be a piece of cake!

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A couple of problems with your study design come to mind.

I gather your goal is to reduce error in current estimation of cook times. This is a reasonable goal. One thing that needs to be stated is the current variance in guestimated cook time vs. actual cook time.

Collecting information from the internet is at best a very poor way of finding reliable data points. There will be many errors during the individual collection of information. (I could report data from memory since I never write anything down but you wouldn't know my collection method) Variation in smokers can't be controlled. There will be differences in the pork itself. Weight of the bone and ratios of fat to meat are just a couple.

My idea of "done" may be different than yours and this could lead to an hour or more of error.

Including data where doors were open should be tossed. This is likely the greatest source of variation in cooktime that can't be defined. For example opening the door for 30 seconds when the outside temp is 92 compared to a 20 second door time when it is 22 degrees will be impossible to evalulate.

The path to accurately defining cook time will require tight control over temperature which is lost when the door is open.

You certainly may come up with a formula that is more accurate than what is currently available. There may be some unexpected discoveries along the way!

OBTW... get humidity, barometric pressure and wind speeds also. Smiler
I tend to agree with Doc.

One thing that is not mentioned is the fact that no two butts are alike - outside fat, intramuscular fat, connective tissue, etc will all have a bearing on the outcome.

I've had small butts (5-7#ers) take longer than 8 & 9 3 butts for no obvious reason. I don't think your "regression equation" would be worth much ( certainly no offense intended ). We all know to average about 2 hrs per pound and even some will disagree with that.

I would like to know exactly when lunch will be served also. As it is, even without scientific data, one's "guesstimate" will be as close as the scientific data and formula developed.

Like you said, truer words were never spoken - 'It's done when it's done!"
I think that you have omitted the biggest variable in determining when the butt will be done, the percentage of the butt that is fat and collagen, and the time spent in the plateau. These two are directly related and probably the most important in determining cooking time. Unfortuantely it is difficult to determine the percent fat and collagen with any accuracy and most do not record temperature on sufficiently fine time centers to help. - Duffey

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