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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 more 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 more
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. 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. Overcrowded
Portabello Mushrooms | | Giving
Mushrooms room |  | |  | Flavor
lacking depth and complexity | | More
savory, meaty and complex flavors |
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? If you want to sauté food
correctly then it is necessary to get a high quality pan. Be sure to look for
a heavy gauge stainless steel with aluminum sandwiched in-between. Such a pan
will distribute heat evenly without burning your food and be highly responsive
to sudden temperature adjustments. A heavy metal plate will also ensure the base
of the pan stays flat and does not warp with use. If the bottom is uneven it can
cause hotspots and allow for unevenly cooked food. References and Selected
Readings: Kitchen Chemistry -- Why do pans stick? Royal
Society of Chemistry Why
is Stainless Steel Stainless? Cooking
with Cast Iron
Pan
Frying
Chicken
Recipe using Sous Vide Cooking
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