A question was posted on Ray Basso's forum about slow dry cooking vs moist/braising.
We have had many discussions on foiling vs slow/fast and I thought this answer provides some food for thought.
Posted by Tom Chilton on January 24, 2004 at 18:50:44:
In Reply to: question about collagen breakdown posted by MaryAnn on January 24, 2004 at 17:35:09:
I looked in my "On Food and Cooking" by Harold McGee, and found some interesting things about collagen, temperature, and dry vs. moist heat.
on p. 111, me says about collagen breakdown: "This process is in some ways the reverse of protein coagulation in the muscle fibers: tightly wound fibers of pure collagen come apart into more vulnerable single molecules as they heat up. The "shrink temperature," the temperature at which the ordered structure of this protein collapses, is about 140� F (60� C) in meat (a mere 105� F (41� C) in fish), and it is only at temperature higher than this that the individual molecules separate from one another in to the loose association we call gelatin. The conversion of collagen to gelatin is most rapid at temperatures close to the boiling point of water, or 212�F (100�C). So if you cook meat rare, just to the point where the fiber proteins are coagulating, exuding juice, and are still tender, the tough connective tissue will be mostly unaffected. But if you cook the meat well enough to gelatinize the collagen, then the fibers will be dry and dense. The only way to get tender fibers and connective tissue at the same time is to cook the meat so long that the fibers begin to disintegrate altogether. But meat treated in this way is crumbly and mealy rather than firm and juicy. Clearly the art of cooking meat lies in compromise."
No more long quotes, but he then talks about roasting and braising - the upshot is that braising actually cooks the meat faster because steam is a more efficient heat conductor than air, so there is less collagen breakdown in braising than in BBQ'ing in dry heat at 225� because the dry heat will take longer to cook. If you wrap a brisket in foil at 160� and put it back in the cooker, you're really braising it, and it will cook faster than if it wasn't wrapped.
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