HALACHA HEATING FOODS ON SHABBAT
I. General Principles
Practical questions of heating food on Shabbat must deal with two potential problems:
1. Actual cooking – a Biblical prohibition
2. Rabbinic restrictions of warming food
1. Actual cooking.
Cooking is one of the 39 prohibited melakhot of Shabbat. It is loosely defined as
affecting a significant positive change in a food through the use of heat.
Not every change is considered significant. While cooking raw foods is prohibited on Shabbat,
reheating certain foods would not violate the prohibition.
In theory, heating the following things would not be problematic:
a) Fully cooked dry foods (even cold), or
b) Fully cooked liquids which have not cooled completely
Practically speaking, the reheating must be done in a way that does not appear like cooking.
2. Rabbinic restrictions on warming food.
Chazal understood that even reheating cooked food might lead people to violate
a) One may give the appearance of cooking.
b) One might adjust the level of the fire in order to cook a food faster.
Additionally, Chazal prohibited the insulation of foods under certain conditions, reasoning
that one who does so might determine that the food was not kept warm enough and
will inadvertently place the food on an exposed flame on Shabbat.
II. Speeding Up the Cooking Process
Not only may one not cook or warm up uncooked food on Shabbat, but one may not
accelerate the cooking process. Examples of this principle are listed below:
Moving the food to the flame area: If uncooked food is being cooked on the blech,
one may not move it directly over the flame on Shabbat because
this will speed up the cooking process.
Reducing volume: One may not release some unheated water in an urn into a glass
so that the remaining water will cook more quickly.
Stirring and scooping:
• Non-fully cooked foods and liquids: Stirring food that is in the process of
being cooked accelerates the cooking process because it causes the food to
cook more evenly by bringing food that is farther away closer to flame.
However, stirring liquid that is in the process of being cooked does not
accelerate the cooking process because there is already an even
distribution of heat prior to the stirring. Accordingly, one may not stir or
scoop uncooked foods (e.g., chulent that is being cooked), but one may stir
uncooked liquids (e.g., chicken soup on a blech that is being cooked).
However, as a practical matter, one should not stir uncooked soup in a pot
because this will require covering the soup pot, as will be discussed below.
• Fully cooked foods: Some halakhic authorities rule that stirring or
scooping fully cooked foods is prohibited while the foods are on a flame
and that stirring fully cooked foods should be avoided in any case.
Therefore, one should not stir or scoop even fully cooked foods while the
foods remain on the flame area. Additionally, some authorities are
stringent and rule that one ideally should not stir fully cooked foods even
when they are removed from the flame area, but one may scoop fully
cooked foods after they have been removed from the flame.
Covering the pot with a lid: Placing the lid on a pot of food cooking on the flame
accelerates the cooking process. As such, one should not cover a pot of non-fully
cooked foods or liquids. Additionally, it is preferable not to cover the lid on a pot
of fully-cooked food or liquid while the food or liquid, as the case may be, is on
the flame area.
III. Ain Bishul Ahar Bishul
The principle of “ain bishul ahar bishul,” literally meaning that something cannot
be cooked twice, is that once a food is fully cooked, it cannot be cooked again.
Therefore, one may reheat a food that was fully cooked once before and merely
cooled off. This principle only applies to dry foods and not liquids. Once a liquid
has cooled down to such an extent that it is no longer desirable to the average
person as a hot drink, then one would violate the Biblical prohibition of cooking if
he would reheat the liquid.
Therefore, one may reheat dry fully cooked foods assuming that they are not
reheated on a heat source. (We will discuss how to reheat foods on a heat source
in Section VI.) For example, one may place matza balls or noodles in a pot of
soup that was removed from the blech. However, if soup had cooled down in a
bowl so much so that the average person would not enjoy eating it anymore, it
would be forbidden to pour it back into a pot of soup, even if the pot of soup was
removed from the blech.
• The definition of a dry food, as opposed to a liquid, is that there is no
significant accumulation of gravy or other liquid. Therefore, moist roast
chicken is considered “dry” for these purposes.
• “Dryness” is determined by the current state of the food. As such,
congealed fat that is on a piece of chicken is still considered “dry” for
these purposes. Note that it is forbidden to melt congealed fat into a liquid
(i.e., where it is not absorbed into chicken) because of molid (changing the
status of a food from a solid to a liquid).
• Even thick, pourable liquids, such as ketchup and heavy sauces are
considered liquids for these purposes. Therefore, ketchup may not be
poured onto chulent that is in a chulent pot that was removed from the
flame because the ketchup would be “recooked.”
• Some authorities are stringent and rule that any food that is dissolvable in
liquid is considered a liquid for these purposes. Therefore, it is advisable
not to add salt to a pot of soup or a pot of chulent even after the pot is
removed from its heat source.
Dry heat vs. wet heat:
• A food is cooked through wet heat (liquid) and is baked or roasted through
dry heat. The principle of “ain bishul ahar bishul” only applies if the
second “cooking” is similar to the first cooking, i.e., if a cooked food was
reheated in a liquid, such as reheating cooked noodles in a pot of soup.
However, challah or roasted chicken may not be placed in a pot of soup
because these foods were originally “cooked” with dry heat so they may
not be reheated through liquid.
• Many halakhic authorities are lenient and rule that only very intense dry
heat of a direct flame (e.g., roasting on a spit over a fire, barbeque on
coals, etc.) can effect halakhic “roasting.” Therefore, one may place
boiled chicken or any other dry cooked food on top of a pot that is over a
heat source (such as an urn or a chulent pot) or on top of a single
temperature hot plate on Shabbat.
• Deep-fried foods, such as french fries, doughnuts, soup nuts and chow
mein noodles, are considered cooked foods for these purposes.
• The status of pan-fried foods, such as fried onions, potato latkes and
pancakes is unclear. Therefore, one should be stringent and not heat them
through liquid or with intense dry heat. However, one may place them on
top of a pot that is over a heat source (such as an urn or a chulent pot) or
on top of a single temperature hot plate on Shabbat.
IV. Secondary Heat – Kli Rishon, Kli Sheni and Kli Shlishi
Halakhic cooking can occur not only from a heat source, such as an oven, but it
can also occur from a material that absorbed heat from a flame, such as hot water
that was poured from a kettle to a glass. There are different forms of “secondary” heat.
Kli Rishon (first vessel): A pot of soup that is on a burner is considered a “kli rishon”
and can effectuate halakhic cooking even after it is removed from its burner.
Therefore, it is forbidden to add cold water to a chulent pot even after the
chulent pot is removed from the heating element because the chulent pot is a “kli
rishon” and will cook the cold water.
Irui Kli Rishon (pouring from a kli rishon onto a plate of food): We assume that
pouring hot food or liquids from a “kli rishon” will “cook” the outer shell of a
solid food but it will not “cook” a liquid unless the liquid becomes hot (more than
110 degrees). Therefore, it is forbidden to pour hot water from a kettle into a
glass containing a slice of lemon and it is forbidden to pour hot gravy from a pan
onto fresh vegetables. However, it is permitted to pour hot water from an urn into
a container of cold water as long as the cold water doesn’t become hot (more than
110 degrees). Additionally, one may pour hot water directly onto a baby bottle
from a kettle or urn because the outer layer that is touched by the hot water is only
the bottle and not its contents.
Kli Sheni (second vessel): Since the walls of a “kli sheni” are cold and constantly
losing heat, it doesn’t have the same capability to “cook” as a “kli rishon.” In
practice, water and olive oil may be poured into a kli sheni. For example, a cold
bowl of soup may be poured back into a hot soup tureen. Moreover, one may
place an ice cube into a bowl of hot soup to cool it down. Additionally,
previously cooked liquids, even when they are cold, may be poured into a “kli
sheni.” For example, cold milk and sugar may be added to coffee in a “kli sheni.”
As mentioned above, sugar or commercially produced table salt are treated by
some authorities as liquids since they are dissolvable into liquid, but since they
are processed, they may be poured into a “kli sheni.” Additionally, soup mixes
and soup bouillon cubes may be added to a “kli sheni.” Tradition soups may be
poured into a “kli sheni” or one may pour hot water from a “kli sheni” into
Tradition soups; provided, however, that one must ascertain that every food item
in the soup is precooked or preprocessed; otherwise, one may not use a “kli sheni”
to permit one to heat the soup. Similarly, one may add hot water from a “kli
sheni” to warm up cold tea or coffee.
Ladle: A ladle is similar to a “kli sheni” because it is not the original container in
which the food was cooked. However, it is similar to a “kli rishon” because it is
first immersed in the hot contents of a “kli rishon,” thereby absorbing much of the
heat of a “kli rishon.” The custom is to treat a ladle like a “kli rishon.” However,
the ladle is considered a “kli sheni” with respect to a previously baked item that is
cooked on Shabbat. Therefore, it is permitted to dip challah (a previously baked
item) into a soup bowl on Shabbat. The pot of soup is considered a “kli rishon,”
the ladle is considered a “kli sheni” and the soup bowl is considered a “kli shlishi”
and the challah, even though it was only previously baked, cannot be
“halakhically cooked” in a “kli shlishi.” However, one may not ladle hot soup
directly from a “kli rishon” into a bowl containing spices, vegetables, bread
crumbs, matzah, or any other uncooked foods or liquids.
Davar Gush (solid hot foods): According to some halakhic authorities, solid hot
food, such as hot chicken, meat or potatoes, retains its status even after transferred
to a “kli sheni” or a “kli shlishi,” so one should not sprinkle uncooked spices,
such as diced onion, garlic, celery, oil, mayonnaise or dressing onto hot solid food
(more than 110 degrees), just as one may not put them in a “kli rishon.”
However, one may pour ketchup on hot chicken because ketchup is cooked during
its processing. Additionally, one may eat hot chicken together with a cold side
dish on the side plate based on a number leniencies. Furthermore, a “davar gush”
that is immersed or partially submerged in a liquid has the status of liquid in this
regard, such as soupy chulent, a bowl of meatballs in sauce, a bowl of chicken
soup with pieces of chicken.
Kli shlishi (third vessel): Rav Moshe Feinstein is of the view that “kli shlishi”
cannot effectuate any form of halakhic cooking. According to this view, a tea bag
may be introduced only into a “kli shlishi.” A “kli shlishi” is the third receptacle
for the liquid. The urn would be the “kli rishon” and the cup into which the water
was originally poured would be a “kli sheni.” The water must be transferred to
another cup before the tea bag can be introduced into the water. Some authorities
are stringent and do not permit one to place a tea bag in a “kli shlishi.” According
to this view, if “tea essence” (concentrate) is made before Shabbat, it may be
poured even into a “kli sheni,” but one should not pour hot water directly from the
kettle or urn onto the concentrate.
Summary of rules of “Cooking” in foods/liquids that are more than 110 degrees &
not on a flame
(1) Definition - (2) Rule - (3) Example
Kli Rishon - 1-Container in which a food or liquid was cooked or heated.
2-One may not heat up anything in a kli rishon except precooked
solid foods and precooked warm liquids.
3-Yes: Add cooked noodles to a pot of soup.
No: Add salt to a pot of soup (absent pressing issue);
add cold water to a pot of chulent.
Irui Kli Rishon - 1- Pouring from the original container in which a food or liquid
was cooked or heated onto liquids or solids
2- One may pour onto cold liquids if the resulting mixture is
less than 110 degrees. One may not pour onto uncooked
solid foods because the shell will become “cooked.”
3-Yes: Pour hot water from a kettle into a cold liquid as long as
resulting liquid is not more than 110 degrees; pour hot water onto baby bottle.
No: Pour hot water from a kettle into a glass with lemon;
pour hot gravy from a pan onto fresh vegetables.
Kli Sheni -1- Container into which hot food or liquid from a kli rishon was directly poured.
2- One may pour certain “spices” (which either dissolve in liquid or
are not eaten with the liquid) or cold liquids into a kli sheni.
One may place processed solids in kli sheni if they will dissolve in the kli sheni.
One may not place non-precooked solids into a kli sheni.
3-Yes: Pour salt or pepper in a bowl of hot soup; place an ice cube, cold water,
sugar or lemon in a glass of hot tea or a bowl of hot soup, as the case may be
(but don’t squeeze lemon); add instant coffee, tea or cocoa to a glass of hot water
to make coffee; add tea essence to a glass of hot water to make tea;
pour Tradition soup mix into a kli sheni or from kli sheni into a soup cup only if
all contents are pre-cooked.
No: Dunk a doughnut in a glass of hot coffee that is in a kli sheni.
(Making oatmeal on Shabbat is prohibited for “non-bishul” reasons.)
Kli Shlishi -1- Container into which hot food or liquid from a kli sheni was poured.
2- One may place roasted or baked solids in a kli shlishi. There is a disagreement
as to whether one may place nonprecooked solids into a klishlishi.
3- Yes: Dunk a doughnut in a kli shlishi; place bag of roasted coffee beans
in a kli shlishi.
Subject to dispute: Placing a tea bag in a kli shlishi.
Ladle -1- Dispute as to whether considered kli rishon or kli sheni
2- One should consider ladle as a kli rishon absent other lenient considerations.
3- When one serves soup on Friday night, one should remove soup fromthe stovetop,
then ladle soup into a bowl and then one may dip challah into the bowl
(which is considered kli shlishi).
Davar Gush -1- Hot solid food.
2- One should consider davar gush as a kli rishon absent other
3- Yes: Margarine on hot potato (margarine is precooked); ketchup on hot chicken;
eat hot foods with cold foods on same plate.
No: Mayonnaise, dressing, oil or raw vegetables onto hot solid food.
V. Sh’hiya (Leaving Foods on a Flame Before Shabbat)
Stovetops: According to Torah law, one may place a pot of raw food over an
uncovered flame just prior to Shabbat because, in this case, no act of cooking (i.e.,
placing the food on a flame) is being done on Shabbat. Nevertheless, our Sages
were concerned that one may inadvertently adjust the flame on Shabbat in this
instance. To solve this problem, most halakhic authorities rule that all raw foods
that are not half-cooked at the onset of Shabbat should not be placed directly on a
flame but they should be placed on a blech (minimally a layer of aluminum foil)
on top of a flame. Some authorities advise that one should cover the range top
with a blech before Shabbat in all instances, even if the food is fully cooked. The
blech serves as a reminder that the flame must not be raised. Some have the
custom of covering the knobs, as well.
If one inadvertently left raw food on a range without a blech that was less than
1/3 cooked at the onset of Shabbat, then one may not eat that food on Shabbat.
To determine “1/3 cooked food,” one should calculate how much time it takes to
cook that food and, for example, if it takes an hour to cook the food, then if the
food was cooked for at least twenty minutes before the onset of Shabbat, one may
eat the food on Shabbat.
Ovens: Many halakhic authorities permit one to leave food cooking in the oven
before Shabbat provided that the food is half cooked before the onset of Shabbat.
On Shabbat, one may open an oven door to remove the food as long as this action
doesn’t definitely cause either an immediate change in the oven temperature or
any lights to turn on.
Crock pots, hot plates, and warming drawers: One may place even raw food on a
single-temperature electrical cooking appliance (such as a non-adjustable hot
plate or crock pot) without a blech before Shabbat. Crock pots, hot plates and
warming drawers with temperature controls are treated as stovetops for purposes
of sh’hiya. See Section VII, however, regarding hatmana (insulating) issues
relating to the use of crock pots with metal cylinder enclosures.
VI. Chazara (Returning Food to a “Covered Flame” on Shabbat)
Subject to the exceptions listed below, our Sages prohibited one from placing any
food, even fully cooked food, directly onto the blech during the course of
Shabbat. The Sages reasoned that placing the food onto a stovetop or a blech or
returning a crock pot into its cylinder gives the outward appearance of cooking.
Exceptions to the prohibition: The only foods or liquids that may ever be placed
directly on the blech are those which were removed from a blech. There are four
conditions under which a cooked food may be returned to the blech:
1) The food must be fully cooked.
2) When originally removing the food from the blech, the person who
does so must intend to return the food to the blech.
3) The food must be held the entire time until returned. (The food may
rest on a surface, e.g., a counter, table, etc., as long as it is being held
by the handle.
4) The food must remain warm.
Note that under no circumstances may one return even fully cooked food
on Shabbat to an oven which is turned on. Additionally, some authorities rule that
one may not return even fully cooked food in a crock pot to its metal cylinder
enclosure even if the conditions above are satisfied and the walls of the cylinder
are lined with aluminum foil, reasoning that this situation is similar to placing
food in an oven. (This stringency would not apply to crock pots that are merely
heated bases with no enclosures.) Other authorities rule that one may return the
fully cooked food in this crock pot as long as the walls of the cylinder are lined
with aluminum foil.
If, inadvertently, conditions two and/or three are omitted, then, as long as
the food is fully cooked & returned to a blech on Shabbat, the food is generally
permitted on Shabbat. For example, if one mistakenly removed the wrong pot
from the blech, expecting not to return it afterward, and then he releases his hold
of the pot, he may return the pot to the stovetop if the pot contains the only warm
food or the main part of the Shabbat meal.
Additionally, only the food that was removed from the blech may be
returned to the blech if the conditions above are followed. Therefore, one may
not remove a pot of soup from the blech, take some cooked noodles from the
refrigerator and place them in the pot of soup, and return the pot to the blech,
because the noodles were not removed from the blech.
Other permissible methods: There are several acceptable ways of reheating food
on Shabbat morning. Reheating food is permissible if there is “no appearance of
cooking.” In the following cases, halakhic authorities have determined that
reheating fully cooked dry foods and fully cooked liquids which have not cooled
completely (and are still suitable as a warm drink) in the following manner
contain “no appearance of cooking” and therefore, one may reheat these type of
foods by placing them:
a) On top of a pot of food or water which is sitting on the range,
b) On top of an urn,
c) On top of a chulent pot,
d) Near a flame, in a place where the food cannot reach 110 degrees – no
matter how long one would leave it there. Such as:
• The side of the range
• The metal between burners of a range (using the heat of the oven or
the pilot light)
• Inside an oven which is turned off but still has a pilot light burning
e) On a single temperature hot plate or in a single-temperature warming
f) On a hot plate and a warming drawer with temperature controls, provided
that, in the case of the hot plate, the knobs and surface of the hot plate are
lined with aluminum foil and, in the case of the warming drawer, the
knobs and surface of the warming drawer are lined with aluminum foil and
the lining extends up the wall of the drawer and juts out of the drawer such
that it is visible when the warming drawer is closed.
g) According to some opinions, on a special “kedeira-blech” – a large
covered pan that looks like a blech but actually holds water,
h) According to some opinions, the food may be placed on even an empty
(overturned) pot or pan over the fire. Many disagree. Still, this is much
better than placing food directly onto the blech or into the oven.
Note: It is important to remember that even if the Rabbinic prohibition of
“chazara” does not apply, one should be careful not to transgress the Biblical
prohibition of cooking. For example, on Shabbat, it is forbidden to warm up a
cold pot of soup on a non-adjustable hot plate. Even though one would not
violate the Rabbinic prohibition of chazara, he would violate the Biblical
prohibition of cooking. Similarly, on Shabbat, even though one may reheat
meat in the ways mentioned above, one may not do so if the meat is covered
with a significant accumulation of gravy. (See III, “Ain Bishul Ahar Bishul” above.)
Transferring from one heat source to another heat source: One may transfer
hot food from an oven that is hot onto a blech that is on top of a stovetop, but
one may not transfer hot food from a blech or from a stovetop to an oven
without an insert. Additionally, one may add hot water from an urn or kettle
to a pot of fully cooked cholent that has dried up. Ideally, the pot should be
removed from blech and the water should come directly from the urn or kettle
into the pot. However, if necessary, one may add water to the pot even from a
“kli sheni,” e.g., from an urn to a cup to the pot.
VII. Hatmana - Insulating
Our Sages prohibited the insulation of foods on Shabbat and before Shabbat,
subject to the rules below. They reasoned that one who insulates his food does so
out of a strong concern that the food will be warm enough for Shabbat and
therefore, if the individual discovers that the food was not kept warm enough, he
is likely to inadvertently place food on a proper flame on Shabbat.
Conditions to hatmana: Four conditions must be necessary for hatmana to be
prohibited on Shabbat if the hatmana retains heat:
1. The food must completely covered by the insulating material.
• Therefore, one may put toweling over an urn as long as a
small but significant part of the urn is left exposed.
2. The purpose of the insulation is to retain or generate heat and not
merely to protect the food.
• Therefore, one may cover a hot pot of food with the lid
because the primary purpose is to protect the food.
• Moreover, one may leave cholent kishke inside the pot while
wrapped in aluminum foil even if the kishke is completely
submerged in the stew because, among other reasons, the
main purpose of covering the kishke is to separate it from the
cholent and not to insulate and retain heat.
• Additionally, one may wrap a hot potato in aluminum foil
and place it in the refrigerator on Shabbat.
• However, one may not completely wrap a hot potato on
Shabbat with aluminum foil to keep the hot potato warm.
3. The wrapping material must be in direct contact with the food
itself or with the outer walls of the pot containing the food.
• Therefore, one may place a tray on top of an urn and then
drape a towel over it because the insulating material does not
touch the walls of the urn.
4. The food must still be in the container in which it was originally cooked.
• Therefore, one may pour soup into a thermos to retain its heat.
Hatmana before Shabbat: Before Shabbat, one may insulate food with a material
if there is no active source of heat present (and the purpose of the insulation is
merely to retain the heat), but one may not insulate food with a material if there is
an active source of heat present (“davar shemosif hevel”). For example, one may
not completely wrap a hot water urn even before Shabbat, but one may wrap a hot
potato in aluminum foil before Shabbat in order to retain its heat. Conditions one
through three above (but not condition four above) must be satisfied to prohibit
hatmana if there is an active source of heat present (both before and during Shabbat).
Crock pots: Some halakhic authorities have ruled that leaving a crock pot with
cooked food inside its metal cylinder enclosure is considered hatmana with an
active source of heat present, reasoning that the close fitting enclosure is
halakhically considered an insulator and there is a heating element. Other
authorities disagree. In order to satisfy all halakhic opinions, some authorities
rule that one should place a crushed can underneath the crock pot. Note that
crock pots that are merely heated bases with no enclosures do not pose a