On 6/12/2012 9:56 AM, spamtrap1888 wrote:
>
> I know what you mean. I cooked a beef roast at 325F the other day. Did
> you know it took well over an hour for the roast's internal
> temperature to reach 140F? What gives?
>
> I think the answer in both cases is that pressure cookers transfer
> heat mostly via steam, while ovens transfer heat mostly via air.
>

I think you're right about this. Steaming is an interesting process.
When the steam hits the cooler food, it condenses on the surface and the
latent heat of the steam is released. It's the opposite of sweating
where the sweat changing into a gas absorbs heat. The energy it absorbs
will again be released when it either turns back into a gas or when it
freezes.