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

[Chana Luntz]

RRW writes:
>     Question 3:
>     Liquids
>     A liquid that has been heated to the temperature of "Yad Soledes
> Bo,"
>     i.e., a temperature at which one would withdraw one's hand from
> such a
>     liquid due to the intensity of heat, is considered cooked.
> 
>     Most Poskim agree that Yad Soledes Bo is between 40 and 45 degrees
>     Celsius, or approximately 110 degrees Fahrenheit.[11]
> 
>     That is the basic rule of thumb for Yad Soledes Bo.
> 
> [Footnote 11 reads:
>     Shabbos KeHalachah, p. 24.
> 
> 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]

See the Yalkut Yosef Hichot Shabbat (vol 4 chelek 3) Siman 318 letter 28 and
particularly footnote 28 there where he brings (particularly relying on the
Ben Ish Chai) a figure of 80 degrees Celcius as Yad Soledet Bo, although he
does agree that between a temperature of 40 degrees and 80 degrees you need
to be concerned that perhaps it is yad soledet bo (ie for going l'chumra).
But meikar hadin he holds an 80 degree minimum (ie that up until that
temperature liquid is vadai being cooked for shabbas purposes).

IIRC the Ben Ish Chai holds the 80 degrees (I have heard others set his
figure at 70 degrees which is closer to Rav Moshe's l'chumra position) which
is determined by the temperature at which a person will eat and drink food
without finding it unpalatable, as being both l'chumra and l'kula.  I would
never have let any of my babies tummies anywhere near 70-80% - so I confess
the Ashkenazi shiurim seem much more intuitively correct (think about the
temperature on those baby thermometers you can buy to stick in the bath
water to ensure it is not too hot, much more in tune with the Ashkenazi
position). 

But you should be aware that while the chumra positions might overlap, the
ikar hadin positions appear to be widely divergent.

Regards

Chana