[Avodah] Rav Melamed on Metal Pots

[Micha Berger via Avodah]

On Mon, Oct 10, 2016 at 07:56:35AM -0400, Akiva Miller via Avodah wrote:
:> So the idea of kefeilah, lekhol hadei'os, is not that ta'am means
:> biological taste. Every shitah has a role for bitul beshishim. And since
:> biological taste is part of psychological ta'am, this combination of
:> ratio and experiment fits psychology more than biology.

: No, not really. Given that the kefeilah is a human who puts the food in his
: mouth and comments on that experience, ta'am certainly does mean biological
: taste..

Well, but then bitul beshishim wouldn't override taste nor would taste
override 1:60 -- none of the rishonim would make sense.

But what I meant was that the kefeilah is a case of psychology. Nothing
creates the expectation of taste as a witnesses's report that it actually
has one. Then the rishonim debate if this is in addition to 1:60,
or is 1:60 is when we would doubt the report, etc...

...
: POSTSCRIPT: In my learning on this topic, I was surprised to find that some
: important data points are not logical or philosophical) svaros, but come
: from the world of Gezeras Hakasuv. I had long known that in the story of
: Klei Midian (B'midbar 31:22-23), HaShem explicitly tells us that metal can
: be kashed via libun or hag'alah. What I learned only recently is that there
: is a pasuk (Vayikra 6:21) that teaches us that pottery can*not* be
: kashered. I saw this in Rabbi Binyamin Forst's "The Kosher Kitchen"
: (ArtScroll) pg 339, based on Pesachim 30b. These Gezeros Hakasuv suggest
: several things to me. (1) Klei Midyan explicitly name iron as one of the
: metals that need to be kashered, and stainless steel is mostly iron; I
: wonder how absorbency experiments can override a d'Oraisa. (2) Similarly,
: glass *is* made of sand; to say that it is a new material, unrelated to the
: earthenware the the Torah says is unkasherable, seems quite innovative.

Except htat

(1) Stainless steel is exactly that -- *mostly* iron, and that alloying
is part of why it holds on to less product than cast iron would.

Also, kelei Midyan is about tevilas keilim, not kashering. They require
the miqvah even if they were never used before; just as something could
need kashering after Jewish use.

If the two correlate, that correlation is not gezeiras hakasuv.

(2) Similarly, glass is melted dust, not dust and water (and other things
to harden the clay) baked until dry.

The question is whether or not they are close enough to the base cases
in the pasuq to be included in the gezeiras hakasuv or not. Given the
ubiquituity of the concept of nosein ta'am, it would seem that Chazal
saw the edges of these categories defined by how they hold on to ta'am.

In fact, the AhS (YD 120:24,25) concludes that Chazal decided glass is
therefore like metal, not pottery. WRT kashrus, tevilas keilim, tum'ah
vetaharah. Sand melted into one lump is more like a nugget of ore (also
found in the ground) than like pottery. And, like metal, both have tziruf
be'eish.

Tir'u baTov!
-Micha

-- 
Micha Berger             What we do for ourselves dies with us.
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