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--AND, HOW
TO PREVENT FOOD FROM STICKING TO PANS--
Stainless
Steel Pan Advantages:
-- does
not react with foods e.g., tomatoes and wine
-- makes excellent sauces after sautéing by dissolving
products of caramelization and mallaird reaction
Stainless
Steel Disadvantages:
-- stainless
steel heats uneven
-- many types of food stick to surface of stainless steel unless
proper techniques are applied.
Why food
sticks to stainless steel pans?
Food that
sticks is caused by chemical bonds that form between the food
and the material of the pan - almost always a metal. These bonds
may be relatively weak van der Waals forces or covalent bonds.
Protein-rich foods are particularly prone to sticking because
the proteins can form complexes with metal atoms, such as iron,
in the pan.
How to
prevent sticking or why hot oil prevents sticking?
The oil,
being liquid, fills in the valleys and caves of the pan surface.
Although the pan may look smooth at a microscopic level the surface
of even the smoothest metal pan looks rough with hills, valleys
and even caves. Hot oil is less viscous than cold oil and will
immediately flow filling the gaps.
When oil in
the pan gets hot enough a steam effect begins to occur
---
"A small amount of oil added to a very hot pan almost instantly
becomes very hot oil. The oil quickly sears the outside of the
food and causes water to be released from the food. This layer
of water vapor ("steam") lifts the food atop the oil film and
keeps it from touching the hot pan surface. If the oil is not
hot enough, the steam effect will not occur and the food will
fuse to the (too) cool pan surface." Source: Ask a Scientist,
Newton
BBC
In addition
very hot oil will react with the metal atoms of the pan and form
a coating called a patina. This leaves few free metal atoms to
react with the food. This coating can easily be removed by detergents,
however, so it has to be reapplied before each use of the pan.
In the case of cast-iron pans the patina becomes more permanent.
It has been suggested that the patina could form by a sequence
of cracking followed by polymerization. Source: Kitchen
Chemistry, RSC
Added Note
about patinas:
"Oil begins to thermally crack near its smoke point and leaves
behind carbon molecules in the patina matrix. All oils are not
the same. They have different smoke points and different carbon
residues. The carbon residue of an oil is a chemical property
that is measured analytically by a Micro Carbon Residue Tester.
The higher the carbon residue of an oil, the more carbon it leaves
behind after its cracking. It is the unsaturated molecules in
the oil that polymerize and bond the whole mass together. The
higher the carbon content of the seasoning matrix (or lower the
hydrogen content) the more durable the patina". Source: Kitchen
Chemistry, RSC
What causes
the sizzling?
The sizzling
sounds you hear are the the sound of water vaporizing on the surface
of the oil. When the sizzling stops that means the temperature
can quickly rise and care must be taken or the food will burn.
Browning occur
when temperatures reach 285F and the Maillard
reaction can occur. A side product of the reaction is water.
So, even as food is browning we will hear the sizzle. Once the
food is completely browned water will not be released and the
sizzling sounds will stop.
Tips to
prevent food from sticking
1. Make
sure the surface is clean. Small attached food particles can
provide contact surfaces of the pan.
2. Make
sure the food surface is dry and not too cold. Let food from
the refrigerator rest for a while at room temperature. Cold meat
sticks easily to stainless steel surfaces when cooked. Remember
if the food surface has water it will lower the temperature of
the oil and promote sticking. You can either pat the surface of
the food dry or in the case of fish with skin, slide a knife blade
over the skin to remove excess moisture. This will also allow
for a crisper skin.
NOTE: some
cooks prefer to add a small layer of oil to the surface of the
dry food to help prevent sticking.
3.Make
sure the oil is HOT. Either add cold oil to a hot pan or start
with a cold pan and cold oil.
Both methods
work fine. However we prefer adding cold oil to a hot pan.
--->Advantages
of cold oil to hot pan --a hot pan requires less oil to cover
the surface perhaps as little as half as much. Hot oil is less
viscous and immediately flows. Less oil will be also be needed
to fill the micro-crevices and provide the necessary barrier between
food and pan surface. In addition the reduced thermal trip to
target temperature will cause the fat to deteriorate less.
NOTE: Some
chefs however prefer adding cold oil to a cold pan some cooks
prefer this technique because the appearance of the oil in the
pan can give you some indication of when the pan has reached the
proper temperature
How to
tell if the pan is hot enough so food won't stick
The oil should
begin to ripple, and spread quite quickly over the pan. If your
pan was hot enough, this process should only take a 'few seconds'
.
Ideally you
want to add the food right before the smoke point. If you wait
too long your pan will get too hot and the oil will start to smoke,
then turn brown after which damage to you pan can occur.
The pan is
hot enough if a few small drops of water flicked from your fingertips
vaporize immediately, or if a larger drop of water hisses and
floats across the surface of the pan on a cushion of its own steam
(Leidenfrost effect).
| Note:
.."The Leidenfrost effect is a phenomenon in which
a liquid, in near contact with a mass significantly hotter
than the liquid's boiling point, produces an insulating vapor
layer which keeps that liquid from boiling rapidly. This is
most commonly seen when cooking; one sprinkles drops of water
in a skillet to gauge its temperature—if the skillet's temperature
is at or above the Leidenfrost point, the water skitters across
the metal and takes longer to evaporate than it would in a
skillet that is above boiling temperature, but below the temperature
of the Leidenfrost point..". see wikipedia |
With experience
you will detect the exact time to add food to the hot oil.
-4. Don't
crowd the pan. Crowding usually lowers the temperature and
releases moisture into the pan. If moisture is released the temperature
will go below that required to produce caramelization and the
Maillard reaction. As a result no browning will occur.
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Overcrowded Portabello
Mushrooms
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Giving Mushrooms room
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Flavor
lacking depth and complexity
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More
savory, meaty and complex flavors
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If necessary,
you should cook food in batches, removing each batch and reheating
the pan and adding more oil as required. Also, unless the recipe
specifically calls for it, do not cover the pan while cooking.
Trapped steam from the cooking side of the food will soften the
top side. Ideally sautéed item have a crispy outside, although
this depends heavily on the food item (sautéed steak: crispy;
sautéed carrots: not crispy)
5. Do not
move the food to quickly. Even if some sticking has occurred
it will most probably be released from the pan after a short time.
If food does
stick and you are using a stainless steel pan, like all-clad,
then lower the heat a little. The food will release on its own.
An exception
is diced vegetables which need to be moved to prevent burning.
A uniform application of oil will eliminate any sticking spots
and produce an equally uniform sear. Heat your pan over a medium-high
to high flame.
6. Listen
to cooking sounds-- Sizzling yes --Splattering no
As long as
you hear that sizzling sound then there's still water in the pan
and foods won't burn. As soon as the sizzling stops that's when
burning can happen.
The end
result-- Crispy outside, moist, non-oily inside
If food is
fried correctly in a small amount of oil the end result will be
a crispy outside and moist interior. If the oil temperature drops
and an insufficient amount of steam is produced the food can obtain
an oily consistency.
When food
is fried with a small amount of oil, the hot oil causes the internal
moisture in the food to boil, which then escapes as steam. The
steam helps prevent the surrounding oil from permeating the food
and making it greasy. The allows for a crispy outside and moist
oily free interior of the food. If the temperature of the oil
drops too low less steam is produced and and oily consistency
is produced.
\What type
of frying pan to use?
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