"Degree Days" rule for BBQ?

[CeramicChef]

 I understand!

[Syzygies]

Woodworkers are known to make rudimentary measurements, and they still enjoy their work!

I wasn't trying to be a troll, but I should have seen some resistance coming. My first year at a Fire Island beach house, I arrived to find that the old timers had claimed all the drawer space. Rather than whine about this, I lugged over a new dresser on the next trip, and made a chart assigning fractions as sizes for the various drawers in the room, suggesting that people be fair in claiming the new drawer space. I faced Kangaroo Court for this, but not because people took offense. They enjoyed having a pet mathematician who could cook, but they wanted to let me know that not everyone can do fractions.

This same crew made me miss the ferry back so I would stay behind to bone out the rest of the chicken I had brought out.

 

[egmiii]

@CeramicChef I made up the three stages based upon my experience to date. Please don't treat these as generally accepted BBQ facts. Throwing some meat on until it probes tender is a simple and proven technique for awesome BBQ. The only problem is it requires some planning and flexibility. It's done when it's done, not a minute sooner. In theory, given sufficient knowledge of the three stages, you could produce similar results to the tried and true method, but in a time span than better matches your time constraints. Possibly even better. Instead of spending 6 hours in the stall and 3 hours breaking down collagen, would you be better off spending 3 hours in the stall and 6 hours breaking down collagen. I couldn't give an opinion either way. But if I were forced to shave off some time to get dinner on the table, it would be nice to know where to cut.

Regarding a drop from 300 to 225. I say, just toss it in the oven. Or just let the grill cool down on it's own. Maybe start the cool down an hour early. Or wrap it in a cooler for a bit. Lots of options!

Maybe all of this is for nothing, but it keeps things interesting, in my opinion. BBQ science and art are not mutually exclusive concepts. Chemical reactions and secret spice blends make for some good eating!

(FYI, if you're accustomed to using SAS / SPSS, check out R. It's slowly become the dominate statistical package. Virtually every university student now uses it, and it's free...)

[tony b]

I retired from Engineering for a reason! This discussion is making my brain hurt. 

[CeramicChef]

13 minutes ago, tony b said:

I retired from Engineering for a reason! This discussion is making my brain hurt. 

@tony b - I'm with you!

@egmiii - another software package replacing SAS and SPSS?  Yeah, R is Open Source and making real inroads.  Free is a great enticement.  I called a friend who teaches stat and is a consulting statistician and he speaks highly of R.  It's now the Big 3 instead of the Big 2.  Alas, R is too late for me!

[tony b]

Most of my career was immersed in probability and statistics. Hence, my reticence in jumping back into a project like this. 

[CeramicChef]

I taught business calc and the stat sequence to both undergrad and grad students.  Loved the grad level stats.  The undergrad calc and stat not so much, but there were rays of  sunshine that made it all worthwhile.  I also did a lot of chaos theory stat analysis.  Not any more!

[wilburpan]

So I’ve been digging into this a bit. There are some interesting characteristics of collagen that I’ve found diving through the biomedical literature.

First of all, collagen is not a pure chemical compound, like water or carbon dioxide. There are many different collagens that vary from species to species and even between parts of the body in the same animal.

Second, it appears that collagen denatures in the 105-115ºF range. This is under laboratory conditions, which may not be completely apply in a piece of meat. But given that the IT that we tend to shoot for with low and slow cooks (195-205ºF) is clearly higher than that range, there’s probably more to the denaturation of collagen to gelatin in a piece of meat than just hitting a given internal temperature.

[egmiii]

Collagen can denature at low temperatures. It breaks down in the human body over a period of days and is recycled. As the temperature rises, it breaks down much faster. I quoted 180-200 before because it breaks down at a pace quick enough tenderize the meat before it dries out. Like you said, it's a very complex process, and varies significantly across different animals / cuts of meat. I routinely add powdered gelatin to my pan sauces. It provides great texture and adhesion to the meat. Kenji Alt-Lopez does an excellent job breaking down the concepts in his book "The Food Lab".

[kennyrayandersen]

OK, I'm a mechanical engineer working as a structural analyst, just so you know where I'm coming from. Ive been BBQing for a decade or so, albeit with a traditional smoker. I love a good equation just as much as the next guy, but it seems to me that in the end, because there are so many variables, that you could only ever end up with something that would give you a range of cooking times. And in the end your personal fuzzy logic is probably pretty good at getting you 90% there anyway and either the temperature probe or the poke test gets you the other 10%! Those general cooking times are probably already available on the internets with a little searching.

[tony b]

@kennyrayandersen - glad to have another engineer on the Forum. Helps keep the science real. 

If anyone has the computational power to do this, it's a serious Monte Carlo trial to develop a multi-dimensional response surface to map this out.  

Not this kid in a million years! 

[ckreef]

BBQ/grilling isn't science - go with the Zen of the cook. It's an art form.

Reef's Bistro

[CeramicChef]

I'm into the Zen camp at this point in life.  I got tired of most the quant stuff when I discovered Woodford Reserve!  

[Stayjoy]

thank you so much for your help i really appreciate it.....................................

 

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[Tucker]

Just finished reading this after my 1st cuppa coffee.

geez, wish I had put a few drops of bourbon in it

I like hard facts, systems of operation and big data.... but, BBQ to me is the fun of it, prep, cook, eat.

 

[Syzygies]

On 7/27/2017 at 2:53 AM, Tucker said:

I like hard facts, systems of operation and big data.... but, BBQ to me is the fun of it, prep, cook, eat.

Huh. An artist worries about "thick over thin" with oil paints, so they don't look like a yahoo after they're dead, with their paintings all cracked in museums. I do believe they're still having fun.

When any of us brings a tray of ribs to the cooker, it's completely instinctive to consider: If I miss the lip of the cooker low, I'll spill my ribs onto the ground. If I miss the lip of the cooker high, I'll be fine. I do believe they're still having fun.

When Dennis worries about heat transfer coefficients for his pizza stones, I know he's having fun.

This isn't about having fun or not having fun, it's about the various realms in which each of us daydream. We're all having fun.

[Tucker]

No offense meant by my comments.

I completely understand the passion each of us have for different things.

[ThreeDJ16]

On 5/31/2016 at 1:00 PM, Syzygies said:

Recall the notion of a degree day. For example, growing degree days add up the surplus heat over a base temperature, often 10 C. Three days averaging 15 C, 20 C, 25 C add up to 5+10+15 = 30 degree days.

What is the best rule of thumb for degree hours in barbecue?

For example, in the thread Dinosaur Beef Ribs, Hector cooked 10 hours @ 235 F. Dave cooked 8 hours @ 285 F. Different pieces of meat, but it was rather evident that Dave overcooked in comparison to Hector. Could one have predicted this by an easy rule of thumb?

A base temperature of 35 F makes these two cooks the same: 10 * (235 - 35) = 8 * (285 - 35) = 2000 degree hours, either way. But 35 F is obviously too low, and we know Dave overcooked compared to Hector.

One can sous vide pretty much indefinitely at 135 F. We have 10 * (235 - 135) = 1000 degree hours, while 8 * (285-135) = 1200 degree hours. That difference is closer to what we observe, studying the two cooks in the thread.

The rate of ideal heat transfer is proportional to the temperature difference, but real world roasting is far more complicated. One follows the water as much as the heat, to understand what is happening. For example, one can model the dwell in a pork butt cook by watching what happens to a wet towel. Nevertheless, a rule of thumb like I propose could be useful for anticipating the effect of small changes in protocol. If I know how long I like to cook a pork butt at 225 F, how do I adjust my cooking times for 240 F? That sort of question could be easily handled by a rule of thumb like I propose, at least for a first guess.

Wow Syz, nice to see you are still around and kickin' on this group (and putting up math problems....LOL).  FYI, my handle used to be Drunk_J many years back when I admined this forum.  Life changes took me away from cooking for many years, but getting back started again with my two beautiful KKs.

Anyway, I don't worry with math, just plug in the BBQ guru, stick a probe in the meat and one in the pit, setup the temp and it shuts down when target is acquired.....LOL.  The lazy man's way and how I like it.  No math, no thinking and really little skill involved with these grills and a temp controller....😁

Hey, who took away all my cool custom emots?  Grrr.

-=J

Edited July 23, 2019 by ThreeDJ16

[Rob.C]

On 5/31/2016 at 3:46 PM, Syzygies said:

Interesting replies. Let's just stipulate that nothing beats experience, and there is a boatload of gotchas and nuances here that any rule misses.

For an interesting parallel, human stock traders have always valued judgment. Yet there was a time when no one had any idea how to value stock options, then there was a rule. People still bent the rule using experience and judgment, but the rule was a good starting point. The traders that started with the rule now live in bigger houses than us. The traders that ignored the rule sooner or later lost their shirts.

Let's confine interest to the practical range of low & slow for large hunks of meat, say 210 F to 285 F, cooking in a KK. You had a plan, but you're starting an hour late. What's your best guess how to adjust your plan? Bend this guess using all the experience and judgment in the world, but start with a baseline guess. What's your baseline guess?

My bias here is that cooks who proudly refuse to measure are foolish. This is most so in baking, but also in salting meat. One needs as much experience as Aaron Franklin to salt as accurately by eye as anyone can salt with a scale. Bend the note using judgment, but start with a number.

I could start a similar thread on a running forum. I kept race records for many years, including my weight, and my race times were best explained by foot pounds per hour. Of course there were nuances, who was I dating? How was I sleeping? What running shoes? Was I training enough? But the rule worked. The philosophy of calculus predicts this; zoom in on anything that curves, and it looks flat.

Asserting a pair of protocols yield the same result is asserting a value for the base temperature in determining degree hours.

To give a formula, asserting m hours @ x degrees = n hours @ y degrees is asserting that (m * x - n * y) / (m - n) is the base temperature.

For example, asserting that 10 hours @ 220 F = 8 hours @ 240 F is asserting that (2200 - 1920) / (10 - 8 )  =  140 F is the base temperature. Using this base temperature, 10 * (220 - 140) = 8 * (240 - 140) = 800 degree hours either way.

So you were planning to cook 10 hours @ 220 F but you find your KK stuck at 240 F. To hell with my math, use your judgment. What is your initial guess how long the cook will take, before you begin prodding and using your judgment, to actually decide when it's done?

I assume there is a time value in meat, but I never knew there was an intrinsic value too. Damn there was a learning curve with options I didn't realize the curve was steeper with meat. Lol. I'm getting a great education on this site. I'm digging deeper and deeper

[Syzygies]

11 hours ago, Rob.C said:

I assume there is a time value in meat, but I never knew there was an intrinsic value too. Damn there was a learning curve with options I didn't realize the curve was steeper with meat. Lol. I'm getting a great education on this site. I'm digging deeper and deeper

Rob, I'm sorry! My new meds are working, and I no longer fall down rabbit holes like this. 

The way to think about any problem like this is to get so much practice that one doesn't need to think at all.