[Avodah] Just How hot is Yad Soledes Bo anyway?

[David Riceman]

Chana Luntz wrote:
> I personally am not totally convinced by the argument in the Yalkut Yosef.
> It seems to me that the default position should be that we ought to be able
> to learn yad soledet bo out, unless we are specifically made aware that this
> is not a situation we can learn it from.  Kli sheni is such a situation, it
> is always made very clear that it is an independent test of cooking (or non
> cooking) that works in parallel to the definitions vis a vis a kli rishon.
>   
I'm not sure what you mean by "always".  The Aruch HaShulhan in YD 
105:19ff seems to view kli sheini eino m'vashel as a consequence of 
temperature and speed of diffusion (which he discusses particularly in 
SK 20).  He doesn't mention heat capacity, though IIRC he uses a crude 
formulation of it in his discussion of tata'ah gavar (later in the same 
siman).

When I was learning YD many years ago my rebbe was opposed to assigning 
particular temperatures to halachic categories, since he thought 
halachic ambiguity indicated delegation of discretion.  In this case his 
argument was, no disrespect intended, anachronistic, since there was no 
known way to measure temperature at the time the SA was written.  I 
wonder, however, to what extent Hazal or the standard poskim would have 
approved of the use of precise measures had they been available.

David Riceman