Is it permitted to pour hot water into a thermos on Shabbos?
The issue involved is hatmana
storing food in wrappers to maintain its heat. As we have previously learned, it is
forbidden to totally enwrap a hot food on Shabbos with intention to maintain its heat.
However, there are two reasons why it is permitted to pour water into a thermos: 1) hatmana
is forbidden only when applied to the original pot, but if the water has been transferred
to a second pot, it is permitted.  2) Hatmana
must be done to a pot, the pot itself is not hatmana, and since the thermos is
considered as one pot with a few linings it is not hatmana. 
The fire under my blech went out, and I would like to enwrap my
pots within my bed linen, may I?
No you may not because hatmana
enwrapping, when done on Shabbos, is forbidden even when there is no heat source
present. You may however, partially enwrap the pots. 
Is it permitted to warm my babys bottle by placing it inside a
pot of hot water?
agree that it is not permitted to immerse the entire bottle into hot water in order to
warm the bottle for the same reason as in the previous answer. You may however, insert the
bottle leaving the top uncovered. 
May I reheat food by placing it on the radiators spread around the
Yes you may because it is not the normal
cooking method.  It is comparable to placing cold
food on top of a pot that is already on the fire. 
However, only dry, cooked food may be reheated; a liquid, or a solid with gravy is
forbidden to reheat.
Is it permitted to
steep cold, cooked chicken inside cholent which is on my plate?
As far as cooking goes, even if the
chicken would reach the heat of yad soledes bo 
it is not a problem for a few reasons, but even as far as hatmana goes, there is no
issur when enwrapping a food within a food. 
As far as fully immersing a cooked egg within hot water a shaila should be asked.
What is the halacha
with regards to immersing the kishke inside the cholent?
We find a few opinions in the poskim
regarding this matter. See the footnote.  HaRav
Shlomo Zalman Auerbach Ztzl held that it is permitted since hatmana is
usually done for the sake of storing heat, and without enwrapping the food from the
outside the heat would be lost. Here the kishke is not enwrapped in the cholent for
the sake of storing heat, rather it is there to get heated by the flame beneath the pot
just as the cholent is heated by the flames. 
Food For Thought
Is one permitted to
put chalah or matza into a bowl of soup?
permitted to make Nescafe in a kli shaini? What about ground coffee?
I like putting
soup nuts (soup almonds) in my soup, is there anything I must be aware of?
Can I spread
mayonnaise or butter inside a boiling hot potato?
Vort On The Parsha
We know of the famous blessings Yaakov Avinu blessed
Ephraim and Menashe by crossing his hands and placing his right hand on Ephraim and his
left hand on Menashe. He explained to Yosef that Ephraim will be greater than Menashe and
therefore he merits his right hand.
The question is then why did he not tell Ephraim to stand
on his right side, thereby avoiding the need to cross his hands?
HaGaon HaRav Chayim of Volozhin explained
that a person tends to magnify another persons faults and shortcomings, and
minimizes his strength and good points. That is symbolized by my right opposite your left
I notice your shortcomings, and my left opposite your right only my weak and
unimportant side recognizes your strong side.
Yaakov Avinu taught us that we should emphasize
another persons strong points and good character by placing my right side opposite
his right, and play down his weaknesses by placing my left opposite his left.