[Avodah] Materials valid for a Keli Sheni

[Micha Berger]

On Mon, May 25, 2020 at 01:52:48PM -0400, Akiva Miller via Avodah wrote:
> https://oukosher.org/content/uploads/2017/10/2017.09-10-Daf25-10g.pdf -
> page 19 of the pdf file, marked as page 57 in the publication)

> > Thermoses and Styrofoam cups are designed to *preserve* heat.
> > Since the leniencies associated with a keli sheni stem from
> > the *cooling* effect of the walls of the vessel, Rav Belsky has
> > stated that Thermoses and Styrofoam cups do not have the status
> > of a keli sheni when receiving food and beverages from a keli
> > rishon.
> 
> It's not clear whether Rav Belsky was talking about Keli Sheni in Shabbos
> or in Kashrus. But even if he was referring to the kashrus implications, it
> would certainly apply to Shabbos as well. According to this, when one takes
> hot water from the urn, it should go into an ordinary keli, not one which
> is designed to preserve heat, so that it would be a keli sheni...

Hatmanah is permitted in a keli sheini. Which you would think contradicts
the above line of reasoning.

But I would suggest that if the keli itself is the insulator, then it's
still hatmanah still during irui keli rishon.

Tir'u baTov!
-Micha

-- 
Micha Berger                 Today is the 46th day, which is
http://www.aishdas.org/asp   6 weeks and 4 days in/toward the omer.
Author: Widen Your Tent      Netzach sheb'Malchus: How can some forms of
- https://amzn.to/2JRxnDF                       "unity" be over domineering?