Why isn't my pork roast ... uh, roasting?

August 1, 2011 7:43 PM

Why isn't my pork roast ... uh, roasting? My almost 4lb pork shoulder has been slow roasting in the oven for about 5 hours and yet its internal temp is still 30 degrees too low.

So I am making this garlic pulled pork recipe. It's been in the oven for over 5 hours at 250 degrees. We have an oven thermometer, so I know the temp is accurate. The pork roast weighs 3.8 pounds and was rubbed with the lime and cumin recipe in the link. It's sitting in a corningware pot in a small pool of cider vinegar.

The meat thermometer reads 160ish, which is 30 degrees too low. What's going on? Is it the corningware? The cider?

posted by slightly sissy tea hound to Food & Drink (24 answers total)

Are you certain the Thermometer is accurate? I would give it a cut and see how it looks on the inside.
posted by tomswift at 7:45 PM on August 1, 2011

Maybe your oven's thermostat isn't accurate? Bump up the oven temp by 30 degrees and see what happens.
posted by killdevil at 7:46 PM on August 1, 2011

Before you cut it open: Is your oven temperature accurate?

(FWIW, when I slow-cook a Boston butt, it always takes longer than I think it should.)
posted by rtha at 7:46 PM on August 1, 2011

Sounds normal. At that temperature, I smoke pork shoulder for 1.5-2 hours per pound. There's a plateau phase where heat converts collagen rather than raising the temperature. You might've hot that.
posted by supercres at 7:47 PM on August 1, 2011

I don't know, but the internal temp only needs to be 145 for it to be safe.
posted by amro at 7:47 PM on August 1, 2011

I also agree with killdevil.. 250 is a pretty low temp for anything other than a crock pot...
posted by tomswift at 7:47 PM on August 1, 2011

I did a pork shoulder low and slow and had the same issue a while back.

More time.
posted by jbenben at 7:47 PM on August 1, 2011

Do you have a crockpot? If so, transfer it over to the crockpot and let it go for a couple more hours. It won't hurt it.
posted by TheBones at 7:48 PM on August 1, 2011

Geez, does anyone read the question?

We have an oven thermometer, so I know the temp is accurate.
posted by amro at 7:48 PM on August 1, 2011

I don't know, but the internal temp only needs to be 145 for it to be safe.

Yes, technically correct, but at 145, pork shoulder would be inedible.
posted by TheBones at 7:49 PM on August 1, 2011

Temperature of the starting roast, shape of it, amount of liquid, temp of the liquid... with the oven temp so close to the temp you want the meat at (250 vs. 190) any little thing can really increase the amount of time needed. If it's 160, it's safe to eat and you can cut up and eat it, but personally I'd err on the side of cooking too long. You can't really hurt it in an oven that cool.
posted by ftm at 7:49 PM on August 1, 2011

Are you basting it? The only danger with a slow-cooked pork shoulder is drying it out, especially if it's boneless and aggressively trimmed. I have to mop mine pretty often to keep it moist.
posted by supercres at 7:52 PM on August 1, 2011

Did you remember to cover the dish? According to the article comments, forgetting that can lead to a similar situation to what you're facing.
posted by fremen at 7:54 PM on August 1, 2011

250 is pretty low, but will eventually yield delicious results. If you're in a (relative) hurry, I'd nudge it up to 275 and check it again in an hour or so. Also, I personally often blast my butt at the end of cooking (like 475 or higher) for a half hour or so to crisp up some crispy bits on the outside, and that also will serve to raise the internal temperature.
posted by trip and a half at 8:01 PM on August 1, 2011

At that temp, a big factor could be the temp of the roast when it went in the oven. If it was still pretty cold, it could take a couple of hours for it to start roasting.
posted by JABof72 at 8:24 PM on August 1, 2011

Did you put it in straight from the fridge? That'd do it.

I also wonder whether that small pool of vinegar is enough liquid. Low-slow cooked meat needs liquid for it to not just become jerky; and the liquid conducts heat into the meat...
posted by fingersandtoes at 8:42 PM on August 1, 2011

Crank the heat up to 350 or so for an hour and you'll be good. I often have to finish off a shoulder at higher heat than my smoker will put out no matter how long I smoke it for.
posted by pwb503 at 8:52 PM on August 1, 2011

Seconding supercres. When you're slow-roasting a pork shoulder, there's a temperature plateau that happens when factors balance out and all the heat energy is going into slowly converting collagen into gelatin, making the pork soft, tender, and pullable. You'll get out of the stall eventually. If you run out of time or patience, you can crank the heat up for a while.
posted by WasabiFlux at 12:30 AM on August 2, 2011

I'm late to the party, but - it could be your meat thermometer. I did this once with a Thanksgiving turkey. No matter what I did, it simply wouldn't heat internally to the proper temperature. After 13(!) hours, I said the heck with it and took it out of the oven. When we went to cut it, it literally fell off the bone. It had probably been done hours before, but the meat thermometer stuck in the turkey's thigh just wasn't registering the correct temperature. Since I had been basting it all along, it was actually still moist and was pretty tasty.
posted by MexicanYenta at 1:11 AM on August 2, 2011

It looks like trip and a half was on to something: I knocked up the temp to 475 for 30 minutes, which was apparently what it needed to push the temp to 190. I let it settle on the countertop for 20 minutes and then we all ate delicious pulled pork (at midnight!). The recipe is highly recommended, with a few obvious caveats if you buy a somewhat larger pork shoulder than what the recipe calls for.
posted by slightly sissy tea hound at 4:50 AM on August 2, 2011

Also, remember that every time you open the oven door you drop the temp in there and add time on, so no peeking!
posted by libraryhead at 6:27 AM on August 2, 2011

Just for posterity, I'm a very serious BBQ guy and I have a smoker with very precise temp control and I find that different pork shoulders take different amounts of time to cook to doneness. It may be a factor of how much fat they contain or how large the bone is or something else, but it is well known in the BBQ community that large cuts (brisket and shoulder) have somewhat variable cooking times. You just have to allow for the longer times when you plan your cook. If it is ready sooner, a hot shoulder, wrapped in foil and then in a towel or two will remain screamingly hot in a cooler for hours, much more time that you will need to allow for the occasional stubborn cut.

Turning the heat up used to be heretical stuff in the BBQ world, with "low and slow" being a real mantra, but with the advent of serious competitive BBQ, it has become apparent that "fast and hot" can also produce winning results. Even when trying for a deep smoke ring, you will find that after the first couple of hours, it doesn't change anything to turn the heat up.
posted by Lame_username at 10:41 AM on August 2, 2011

Also, if it was originally frozen and you defrosted it, the center may have been significantly colder than the outside, so take longer to get up to heat.
posted by telophase at 10:49 AM on August 2, 2011

To calibrate your meat thermometer, get a styrofoam cup and fill it with smashed ice cubes. Then fill it with water. Put the thermometer in there and swirl it around. Should say 32 deg F.

If the thermometer is not broken, this ought to assure that it is calibrated right.

If you want to verify it, get a pyrex measuring cup and boil some water in the microwave. (Literally boiling.) Take it out, and swirl the thermometer around in it. It should go up to 210-ish.

If you are accurate at both points, you have an accurate thermometer.
posted by gjc at 7:02 AM on August 3, 2011