Calling Vernon N, Engineers and Mathematicians.


 
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Rob O

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Hi folks. I'm gonna apologize ahead of time for sort of an eggheaded post but sometimes my mind gets wandering and I can't stop where it's headed. I've been thinking about this for a while so here's an idea for anyone who's interested.

The (very general) concept: Could it be possible to develop a mathematical model for the expected times and temperatures to cook BBQ within certain variance parameters? If so perhaps we could build a "BBQ cooking calculator."

Before you fall off your barstool backward laughing:

In simpler terms how many times have you seen a post that says " I'm cooking a (name the meat and poundage) it's currently at XXX degrees. How long or how much longer should it take to cook? And how many times do you see answers that vary by as much as 60 to 70 % per pound?


I'm an economist by training but haven't practiced it for a while. So my math's a little rusty. As a cook I know there are lots of variables to be defined here.

But, spoken as an economist
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, assume we could define the proper variables and had sufficient data. As such shouldn't it be possible to define a probablistic model for how long it should take to cook a particular type of meat given certain starting temperatures and other relevant conditions?

What I'm proposing is if we could get the variables defined properly perhaps we could start a project to get people to post relevant data, perform the proper analysis, and possibly build a calculation engine.


I'm sure I'm going to take my share of razzing for this post and I understand why. But, if there's any interest out there it could be an interesting project for a few of us and if we're successful it might actually be useful to a lot of us.

Thanks for humoring me.
 
Don't want to discourage anyone from doing great things in the name of BBQ but, unless calculator users all get a Guru and smoking jacket, cook identical meats on calm 70ºF days using the same fuel I think the calculator would be about as accurate as asking a psychic how long the cook is going to take.

How do you plug in 'hmm, a strong breeze came up overnight, temps were all over the place' or 'darn, WSM ran out of fuel 2 hours ago and temp has been slowly decreasing' to an equation?

If you do proceed best of luck. Hope it works out or at least you have fun doing it.

I gave a similar suggestion (asked a similar question) when I first started. I think Jim laughed at my suggestion too
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Rob,
I won't laugh at you, but I will laugh *with* all the people who are laughing at you
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There are too many variables. I'll elaborate on Shawn's contribution: Given perfectly spherical meat of uniform density with your BBQ operating at standard temperature and pressure (outside the BBQ, that is) you might have a chance.

Apply Occam's Razor. Use a thermometer.

good luck with the calculator
morgan
 
Good luck, and I'll be glad to help if you decide to proceed. Don't know how much help an Automotive (mechanical) guy will be though. I guess I could make you 3D cad models of meat.
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This is one engineering 'type'(actually don't fit the type well) that tries not to think (at all) once I walk out the front door in the evening. I leaves the office, in the office. But I do sketch ideas for fun stuff at home. WSM mods and such.
 
No matter how much science we have, BBQ is still an art.

I must respectfully choose not to accept this mission due to incomptence and lack of time. While in college, I sucessfully figured out how to skip thermo and still get a civil engineering degree. I am proof positive that you can get advanced engineering degrees in sanitary engineering and not be able to calculus my way out of a brown paper bag.

As pointed out above, there are many variables starting with the fact that each similar piece of meat is different, heat and gas flow in each WSM would be different, monitoring locations are different, the charcoal load and burn are different, exterior weather conditions are different, etc.

If we could develop such a model, it would rival the various weather models and aviation/space finite element models in complexity, require hours on a supercomputer per run and probably require the resources of the federal government to develop. Once we had the model developed, by the time that we could get the configuration data in for the specific cook, the BBQ probably would already be done.

The most useful thing that I have found is tracking the temps in graphical form which allows comparison to previous cooks and allows projection of the trend line. I have been remiss in getting my information up on my web site so that others can use it. I think that it would provide some guidance to new users. I was not aware of the 160 plateau on my first cooks with butts so I thought I had problems. If I had seen a few graphs of temp/time I would have not been so crazy trying to get the temp rise back on track.
 
Rob O

Find yourself an interested grad student to tackle this one. I've done some math modeling of different thermo issues, but the real world is the real world and can be difficult to model. A lumped approach wouldn't be sufficient as any BBQ meat is pretty nonhomogeneous thus necessitaing a pretty good model of the meat as well. Not saying its impossible, but I'd have to agree that BBQ is as much art as it is science.

On a related point, on my thrermo final (too many years ago), the main question was to estimate the time it takes a hot dog to come to an internal temperature of 180 degrees in two mediums, boiling water and in an oven at some temperature I can't remember.

Saw a great picture a coulpe months back of a guy at a competition who had some 20 odd temperature measuring devices of various sorts plugged into his bge and wsm complete with a laptop for all data recording. Maybe he'd figured it out.
 
Rob
I was laughing at me cause I didn't understand the question.

When competing we have a specific time that the meat must be turned in so every cook has a plan.
If I cook this meat of this weight, at X temp I should be within the window with tender moist product. These plans work so I believe a model could be built. The biggest variable, as I see it, is the piece of meat. The meat varies so much when it comes to connective tissue and fat content I got to believe it would be hard to come up with enought meat with the same amount of connective tissue and fat to get real good base set to work from.

Would be interesting to know how you could measure connective tissue and fat in a piece of meat. Being able to measure that would be real handy in picking out meat to be used in a competition. You come up with that I would be very interested in your findings.

Rob, your mission, if your willing to accept it, is to go forward with this study and report back your findings.
Jim
 
Rob
I was having a think about this (despite my previous post) so came back to this thread.

If you (for the now) disregard the qualitative aspects of the meat and concentrate on the ratio of mass/surface area you might be onto something.
i.e. 1 kg of 1cm thick steaks will cook quickly,
a 1 kg cube of the same meat will take much, much longer.
You can immediately see the difficulty in measuring the surface area of a lump of meat.

morgan
 
Hope I didn't cause offence Rob. It's a great idea, to be able to know how long it will take, I'm just skeptical about it.

Two more difficult variables are personal preference and "it's done when it's done". The latter suggests it's not done 'till the pitmaster says it's done, not by when the Polder or ET-73 or calculator says it's done. Certainly they are great tools though.

Maybe someday I will know instantly by sight, touch and smell "when it's done" and be able to look at a chunk of meat and consistently judge how long it will take +/- 60 minutes. I think that's the real mastery.
 
I'm just glad Rob isn't Edison thinking about ways to illuminate a house using electricity, or one of the Wright bros thinking he could fly with a gas powered thing made from bicycle parts, cloth and cables. Your support is under-whelming. A couple of years ago, you all would have thought the Guru guys were crazy to think that they could control the temp of you smoker just like you do your oven. Much less with a ramp up and ramp down feature.
Got to get back to work. Designing a vehicle that travels the roads and squirts water on fires.
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> I'm just glad Rob isn't Edison thinking about ways to illuminate a house using electricity, or one of the Wright bros thinking he could fly with a gas powered thing made from bicycle parts, cloth and cables. Your support is under-whelming ... <HR></BLOCKQUOTE> There is a lot of support in the thread for Rob and his mission, including from me, but practical issues for consideration as well. I don't think it's wrong to express doubts or concerns in a discussion forum.
 
I'd say that, as long as we're talking about barbecue, we're going to have continue to be forced to rely on empirical evidence. There is one food, however, that is always the same weight, that can be cooked at a specified temperature and always takes the exact same amount of time to cook every time-- it was invented 50 years ago by Gerald Thomas of the C.A. Swanson & Sons company.
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Rob,
It won't work! After having a pork butt cook an additonal 6 hours from where I usually pull it, (all cooked with Guru at same temp) I'd say it's impossible to calculate exat times or even close times. Sorry to burst you bubble, but half the fun is anticipating!
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Nick P.
 
Hi all,

No offense taken and I'm glad it gave a few folks a good laugh. I actually learned a bit about how people think. Economists tend to think in terms of academic models which is what I was doing. It was facinating to see how the engineers started to define models and methods of measurement and Nick P, as a contractor went straight to the pracitcal.... How the he*l are you gonna get this to work?


That being said I still think this is possible although the trick would be to see if it could be made practical.


For anyone who's still interested I think this problem might be handled if we approached it as a statistics problem. There's a technique called regression analysis that allows you to create mathematical models that predict an end result provided you have sufficient historical data.

If anyone's still interested in the discussion there are also ways of handling things like the varying thickneses and fat contents of meat by using something called a normalized distribution curve.

But all of these techniques would require sufficient data and I admit I'm a long way from figuring out what data to get and how to get it.

OK, so if I haven't completely alienated everybody still reading and there's any interest out there in trying to model this experiment let me know.

If not don't worry, no harm done, I'll keep noodling this around in my head to see if there's a way to make it less complex.
 
Rob,
I bet if you got a keg of beer and we all sat around and drank for an hour or so we would have an answer for you pretty quick!!! Otherwise, I dunno???
 
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