[Avodah] Kosher

[Isaac Balbin]

R' RRW
>    The Laws Of Cooking On Shabbos
>    Based on the Sefer Shabbos KeHalachah
>    by Rabbi Y. Farkash
...
>    Most Poskim agree that Yad Soledes Bo is between 40 and 45 degrees
>    Celsius, or approximately 110 degrees Fahrenheit.[11]
...
> To which I would add: In contrast, Shemiras Shabbos Kehilkhasah 1:1
> gives only the top of that range -- 45deg C, 113deg F. Gives it as a "lo
> pachos mei-".
> RMF in IM OC 4:74-75 gives a range. 110deg F lechumerah, but WRT an
> item being cooked before Shabbos, so that colder is qulah, RMF requires
> 160deg F.
> -mi]

Rav Soloveitchik personally experimented and felt that it was 140
(60C). He felt the range was between 140 and 160 F.

Others (Shmiras Shabbos) quote the Yerushalmi saying it should be based
on the blood temperature of beis hashchita for which we know the knife
is not boleah, based on Gemora in 1st Perek Chulin. Shmiras Shabbos says
the warmest is 113, so he is machmir from 114 onwards.

OU are machmir (it's lehokel of course in bishul akum/treyf) for 120 F
(which you can barely feel)