Current thought is 12 hours at 76C, unless anyone suggests different.
The only reference on the web I can find is Chris Staines from 2005 http://www.catererse...-big-sheep.html which is bizarre: 20 mins at 80C, then roast 20 mins at
180C. I cannot imagine the heat penetrating the meat in that time, nor the collagen dissolving, so I guess there is a misprint.
You see this is what doesn't make sense to me.
In "Mastering the Art of French Cooking", Julia Childs et al speak of a final core temperature for lamb/mutton (incidentally, no difference between them in cooking times and temps they say) after traditional cooking, of 170F as being distinctly "well done", and 160/165F (~72C) as being preferable. And for "medium rare" Childs et al suggest a final core of just 145 to 150F (~64C).
I'd have thought that equilibrating the whole lump at an even higher temperature than that suggested traditional final core
(for "well done" meat), and holding it there for, say, another 8 hours was going to result in "overcooked" meat.
I've been thinking that one picked the equilibration temperature as matching, or rather determining, the desired "degree of doneness" (and that holding it at that temperature shouldn't/couldn't overcook it in any reasonable timescale). But yes the length of time held at that temperature should be long enough to complete any desired processes that will happen at that temperature, whether for hygiene or tenderness sake.
I appreciate that you want to hurry along collagen breakdown, but it seems to me as though 76C is rather higher than I'd expect.
Are you planning any additional higher temperature Maillard browning and flavouring, as with the recipe you linked?
It strikes me that if you are tight for time, then (from nathanm's tables) reducing the meat to thick slices before cooking, would give you at least an extra 3 hours or so of "time at temperature", which, in the context of a 12 hour total timeframe, looks as though it might be significant.
However, personally, I'm just trying to get my head around this stuff, before
I go and add a PID and vac-packer to my cluttered life!
So, I look forward to hearing what course might be chosen, and what then resulted, not least to develop my own understanding of this mysterious niche.
Edited by dougal, 08 February 2008 - 07:04 PM.
"If you wish to make an apple pie from scratch ... you must first invent the universe." - Carl Sagan