In reply to andrewmcleod:
> As a physicist, this is one of those complicated things best worked out either empirically (by testing) or numerically (which would itself need to be informed by testing).
Or by making further approximations. Assume that the object can be modelled as uniform, with a uniform temperature at all time (valid for a suitably slow process), and that the process is time-reversible (it is), and then apply Newton's law of cooling:
dT / dt = kT
where T is temperature, and k can be calculated from a few assumptions from the object (relative SHCs of the meat, the air, etc).
This equation is trivial to solve, by the way. T here is really (T(object) - T(environment)), so you just want to work out k (dimensional analysis will help you here to work out the ingredients (heh) required), integrate in t with the initial condition (t = 0, T = t(object)), then set T = 0 to give you t when the objects are the same temperature.
Works out (up to a minus sign) as:
t = kT
where T is defined as above (temperature difference). The trick is in calculating k. That is left as an exercise for the reader
Simples!
Post edited at 19:29