A large rock(!) helped me slow cook a pork roast last night!
Okay, let me say up front that it was not my intention to use a rock. I had a 7# pork shoulder roast that was longer than it was thick. Too long to fit in any of my Dutch ovens. But I have a large diameter pot that isn't terribly deep but I THOUGHT it was deep enough. This recipe has you brown the meat, then roast at 450 for 30 min. uncovered. Then reduce temp to 250, cover and cook 8-10 hours, basting every hour or two. At about 4 hours, it will probably have reached 190 and then you cook on til falling apart. Well, when I went to cover the pot after 30 min., it didn't fit by a good 3/4". Went outside and got a really big rock (cat weighs 5# and it weighed WAY more than she does) and weighted down the lid. Correctly figured that after a couple of hours, the meat would have reduced in size enough that I wouldn't need the rock. I did notice that that rock retained its heat for a LONG time. Well, after 4-1/2 hours, I went to check the temp and baste...and the thing was done --- mouth-wateringly, falling off the bone done. Boy, was I surprised. So forgive the fact that I've blethered on, but I DO have a question. Do you think the rock created a convection type of environment that caused it to cook that much faster? Though it was a rectangular piece of meat, not squarish, I just don't believe that the thickness was enough of a factor. After all, it weighed almost 7#. I'd like any opinions on this. I'm definitely keeping that rock around :) And, maybe with my Costco rebate, get a bigger Dutch oven. Thanks all.
PS: I've cooked this before and the timing was the longer amount I mentioned.
yes, c oliver, the rock (once it got hot) helped by transferring heat through contact (as opposed to heat through air, which is less efficient) -- but not by convection, which is moving air. <edit, buttertart's post made me re-read your's. i see the rock was on the lid, not the roast. so the lid of the dutch oven was the contact surface, as it was "squashing" the roast underneath. i'm sure the rock also helped to heat the lid. btw, what of the lid's handle?>
but, the bigger question for you is when are you going to gather an inventory of big rocks, in order to have williams-sonoma feature them in their spring catalogue? i'd say you should expect them to sell the rock for $145, so work back your margins accordingly. ;-).
if you sell it WITH a dry rub for the pork, add another $50.
ooh, marketing idea: you can have different "models" for the status-conscious.
ladies, do you want to be terribly british?: try the "brimham rocks" model: http://www.brimhamrocks.co.uk/
gentlemen, are you up for these all-american rocks!?! get your boulders here! http://en.wikipedia.org/wiki/Rock_City,_Kansas
you can go here for more "models" http://www.scienceray.com/Earth-Scien...
Regarding the lid's handle...the rock is kinda football size and the pot/lid is probably 14-15" diameter so I was able to set on one side. It didn't give me a perfect seal but I figured at 250 degrees I probably wasn't going to lose a lot of moisture at least early on.
I SO like the WS idea!!! I got this recipe from Will Owen and it DOES have a rub of garlic, fennel seed, red chilies and salt. And I DO agree that $50 is a fair price. You're too funny.
Heat transfer from solid to solid is faster than from air to solid, so it's quite possible that it cooked faster because of the rock. Or perhaps you created a sort of pressure cooker by putting extra weight on the lid? This would also make the meat cook faster. In any case, I especially liked your estimating the weight of the rock by comparing it to your cat's weight. A cat-based worldview is a fine thing.
No, frankly I don't think the rock had anything to do with your pork. Others have mentioned it, but rocks and convection have nothing to do with each other. Convection ovens are ovens that blow heated air and circulate it around the oven. The rock did not cause the air to blow around inside the oven.
I don't think it caused any significant pressure differences either. While it might have very slightly increased the pressure in the pot, the seal is far to weak to do any good. Real pressure cookers create lots of pressure.