[Avodah] May one add matzah meal or pieces of bread to a bowl of hot soup on Shabbos?

[Prof. Levine]

I have never understood the assertion that "a kli shlishi definitely
does not cook."

When I make a coffee on Shabbos morning, I take the water from the
urn and put it into a cup.  I then pour this water into another cup
which is then a kli shlishi.  However, the temperature of the water
in the second cup is still very hot.  Indeed, if I poured it onto my
hand I would get scalded.

How much difference can there be between the temperature of the water
in the urn and the temperature of the water in the second cup,  the
kli shlishi? Not very much.  The temperature of the water in the
second cup is certainly well over 113 F. So why do they say it does not cook?

At 05:05 PM 1/12/2021, Micha Berger wrote:

 > From Peninei Halakhah 10.11 "Cooking after Baking" at
 ><https://ph.yhb.org.il/en/01-10-11/>:
 >
 >     Following the custom of most Jewish communities who are stringent
 >     in this regard, one who wishes to dip a cookie in tea or coffee must
 >     make certain that the teacup or coffee cup is a kli shlishi, since a
 >     kli shlishi definitely does not cook. One who wishes to dip bread in
 >     a bowl of soup may do so, as the ladle used to serve the soup can be
 >     considered a kli sheni and the bowl can be considered a kli shlishi
 >     (MB 318:45)[10].
 >