My temperature is rising!

January 31, 2015 7:06 PM

I smoke meats. I love low, slow cooking. However, I really want to understand how fast temperatures rise. I have been searching for, without luck, some kind of chart that will show how quickly internal temperatures of meat rise.

So, my question is this:

If I have a 6 pound pork shoulder, at an internal temperature of 60 degrees, and cook it at an oven temperature of 210 degrees Fahrenheit...how long will I need to cook it to get it to an internal temperature of 205?

I am experimenting with how low I can cook pork shoulders and what my time requirement would be. I have tried in the past, used my power of dead reckoning, and have had good results. However, I'd like to be able to sleep overnight, while I am cooking, without worrying that my roast has turned into an overcooked hockey puck.

Any help would be very appreciated!!

posted by zerobyproxy to Food & Drink (11 answers total)

Getting it to 205 in a 210 oven? Almost forever. Much longer than you want, anyway. I personally always do a 225-250 smoker to a temp of 198 at about 1.5-2 hours per pound. A few hours extra make no difference. The actual temperature by time function is probably roughly logarithmic. It's going to depend mostly on the specific heat (i.e. meat type, fattiness) of the roast or whatever.

The problem I've found with pork is "the stall"-- at some point around 180F the internal temperature of the meat stops rising and all heat goes into converting collagen to gelatin. So it's not in any way constant; there are tons of chemical reactions going on behind to scenes that make the physics of the process nonlinear.

If you're cooking something as uniform as, say, a pork loin, though... The app Sous Vide Dash is actually really good for idealized situations; different culinary application, but really similar principles of heat transfer.

Fortunately pork shoulder is really hard to mess up. If your smoker has a thermostat, you would have to TRY to make it a hockey puck, even sleeping al night, and probably all day too.
posted by supercres at 7:28 PM on January 31, 2015 [6 favorites]

I have read some detailed explanations of the stall, but I just use an internal temperature probe and watch for the rise after the stall, whenever it ends up happening.

Watch out also that oven thermometers tend to be quite inaccurate, so just putting the dial on 210 is no guarantee of what temperatures are happening inside.
posted by Dip Flash at 7:43 PM on January 31, 2015

Response by poster: I don't mind that it takes a really long time. I am very curious what it will be like though. I wonder if it would affect the stall time because it will have been at a constant low temp for so long. Usually it sits for about an hour at 180.

I totally agree with you around timing on the smoker. I generally smoke shoulder for about 4 hours or so (about the max smoke the meat can absorb before the proteins denature) and then bring it into the oven to finish for as long as it takes to get to 205.

I am really trying to determine rise and run. So, to move the shoulder from 60 to 205 at a 210 clip (stall withstanding)...what is known? Can I expect 6 degrees per hour increase? Less? When I smoke at 250 degrees I normally get 8-10 degrees temperature increase per hour.

Thanks for your answers!
posted by zerobyproxy at 7:49 PM on January 31, 2015

Best answer: If you were seriously motivated, you could spend an hour or two writing out the poorly formatted formulas used in this forum post on paper into their generic forms, then plug your numbers into a computer algebra system to try and get a handle on the mechanics. Sounds kind of like a fun exercise, to be honest.
posted by oceanjesse at 9:04 PM on January 31, 2015 [1 favorite]

Best answer: Here are some specific heat values for various foods that you could use in your differential equation.
posted by oceanjesse at 9:08 PM on January 31, 2015 [1 favorite]

Best answer: So if you really (like >$150 really) want to know you could avoid the PDEs and just go for some nice empirical data using something like a USB thermocouple reader.

You could stick a thermcouple into the meat and measure the temperature as a function of time and save it to a PC. Do a few trials with different meat sizes and cuts and you could generate a reasonably accurate look up table. You'd also be able to see "the stall" directly.
posted by TimeStove at 9:13 PM on January 31, 2015 [2 favorites]

Amazing Ribs has a nice article on the topic for meat smoking, also done low and slow.
posted by fremen at 10:12 PM on January 31, 2015 [1 favorite]

And then there's "the stall". At around 160 degrees the meat's internal temp will stop rising for a rather long period of time as internal moisture "sweats" and effectively cools the meat. Again Amazingribs.com has good info.
posted by Gungho at 8:34 AM on February 1, 2015

Best answer: It is very difficult to generically model temperature rise in meat. This is because every cooking environment is different (how much air circulation? what is the humidity? how large is the cooking environment and what is it made out of? what is the heat source? and so on), there are large differences in ingredients to be cooked (how large is the meat? how wet is it? is there a fat cap? what is the shape of the meat? are there bones and are they exposed? and so on) and there are large differences in cooking style (is the meat mopped or basted? is there a crust? is the meat pre-seared or started at high temperature? and so on). The only good models I have seen are for sous vide environments, where most of these variables are eliminated.

A major variable, and what leads to the "stall" that people used to think was due to collagen converting to gelatin, is the "wet bulb temperature." Effectively what this means is that, while there is liquid on the outside of the meat, the hottest the outside of the meat can get is 100C. This, needless to say, has implications for how hot the inside of the meat can get and at what rate. During the early part of the cooking process, the meat transfers moisture to the outside surface keeping it moist and therefore no higher than 100C. This is why the temperature will be seen to rise until a certain point, and then plateau for a while. This plateau happens because the outside of the meat is still wet and the meat has reached the maximum internal temperature it can reach with an exterior at only 100C. Eventually, however, the outside of the meat dries up and the external surface goes over 100C. This is when the "stall" will stop and the internal temperature will be seen to rise again. Mopping and liquid basting re-wet the external surface and work to limit the temperature rise, while basting with fat can help to dry out the external surface and increase the temperature rise.

If you want to find an answer for your specific circumstances, the easiest thing to do would be to experiment on a weekend when you can check the temperature every few hours. Then you will know how long it takes and so long as you do more or less the same-sized piece of meat in the future, it should work out more or less the same.
posted by slkinsey at 2:42 PM on February 1, 2015 [2 favorites]

Best answer: Look here for a good description:

The Chemistry of the Barbecue "Stall"
posted by slkinsey at 3:38 PM on February 1, 2015

I came in to echo what slkinsey said. Nathan Myhrvold is one smart cookie and has spent a large amount of time and effort understanding this topic. He's also (apparently) an award winning barbecue competitor (in addition to being the badass that published Modernist Cuisine).
posted by conradjones at 6:00 PM on February 1, 2015