Blech - literally means metal. It
refers to the metal cover plate that
is placed on an open flame in order
to cover it on Shabbos.
Heating any uncooked or partially
cooked solid or liquid food to a
Temperature of 113 degrees F, Yad
Soledet Bo, or higher is termed
3: Ein Bishul Achar Bishul - "There
is no cooking after cooking/" Fully
cooked solids are not able be cooked
again. However, liquids can cook
again and may not be reheated.
4: K'deirah Al Gavy K'deirah - a
vessel on top of another vessel,
e.g.. a pot containing food on top
of another pot containing food.
5: Yad Soledet Bo - Laterally means,
"a hand can be placed on it". That
is, if you can put your hand on a
heat source without burning you
hand, you may use that as warming
tray or blech because no cooking
will occur. This temperature is
generally agreed to be 113 degrees
Halaching Principles Related to
Cooking as, defined above, is not
permitted on Shabbos. Placing fully
cooked foods directly over a flame,
or any source of heat that can be
used for the purpose of cooking is
"Putting food onto a flame resembles
cooking and may lead to actual
cooking." This is related to the
principles of N'Shinah L' Chatchilah.
Placing full cooked foods onto a
source of heat in a way that
resembles cooking is not permitted.
Melting fat, or heating cool liquids
[even if previously boiled] by
placing them on source of heat, is
forbidden, even if a K'deirah is
Food may kept on a stovetop if the
flame is covered. Covering the
flame indicates that you are not
concerned with adjusting the flame.
Therefore, some authorities also
require that the knobs be covered or
removed for the same reason.
Returning food to a blech.
Foods may not returned to a blech
unless the following conditions are
The food is fully cooked before
The food must still be warm at the
time of returning it.
The pot must still be in your hand,
i.e., it was not released from your
Your intention was to return the pot
to the blech before you removed it.
Foods that have cooled down
may be placed near [not directly on]
a source of heat, to remove the
chill, if there is no possibility of
it reaching Yad Soledet Bo 133
degrees F. Or, unless, a K'deirah is
Foods may be returned only to the
areas of stand blech where the
surface temperature is cooler than
Yad Soledet Bo, 113 degrees F. This
bearly warm to the touch.
THINGS TO REMEMBER
The Un-Blech is both hotter and
colder than a standard blech. To
make sure that your food gets hot
use short wide dishes like a
casserole to warm foods.
Use a crockpot for chulent.
The entire surface is permitted for
Drain the fat from the meat or
chicken that you intend to rewarm on
Shabbos before Shabbos, so the
problem of melting fat is not an
Bake or broiled foods may be
rewarmed on Shabbos.
Food like rice which are boiled,
raise questions. Some feel that they
may not be reqarmed others do not
see a problem since the Un-Blech can
not be used to cook foods. Ask your
can be left on the Un-Blech for long
periods of time in short wide
dishes. the temp of the food must be
at leat 125 degrees to prevent
spoilage. If your Rov is not
familiar with the Un'Blech, it is
best to bring it to him when you ask
your questions. As your Rov about
warming specific goods.The k"deirah
is, to mu knowlege, the only new
blech that has been examined by
A partial list follows: Rav Dovid
Feinstein, Rav Herschel Schecter of
YU, Rav Kenneth Auman of Young
Israel of Flatbush, Rav Dovid Cohen.
time users - note--before using your
Un-Blech for the first time you
should calibrate the burner that you
intend to use with the K'deirah.
should be done during the week so
you can get the best setting for you
range. This is a most important
step. Too high a flame will cause
the water to boil out before the end
1. Bring about 6-8 cups of water to
a boil in a pot or use instant hot
from the sink.
2. Remove the teakettle from the
burner and reduce the flame so that
it is about 1/4 inch high. (On many
ranges this will conform to the
first detent or click that you feel
as you turn the knobs to adjust the
Electric ranges work perfectly well
with a K'deirah Blech. However,
since electric coils are much hotter
the a gas flame, adjust the
temperature so the