SAFE COOKING WITH OIL
The Smoke Point
Knowing the smoke point can also save you money, because each time you deep-fry,
you lower its smoke point irreversibly. If your oil's smoke point is just above 190
degrees C (375 degrees F), which is the normal deep-frying temperature, chances are
its smoke point will drop below 190 degrees C (375 degrees F) after its first use,
rendering it useless. If you want to save money by reusing an oil as many times as
possible, select one with a high smoke point.
Smoke Points
Safflower 265 degrees C
Sunflower 246 degrees C
Soybean 241 degrees C
Canola 238 degrees C
Corn 236 degrees C
Peanut 231 degrees C
Sesame 215 degrees C
Olive 190 degrees C
Lards 183 to 205 degrees C
A number of factors will decrease the smoke point of any fat:
- combination of vegetable oils in products
- presence of foreign properties (batter)
- temperature to which oil is heated
- presence of salt
- number of times oil is used
- length of time oil is heated
- storage of oil (exposure to oxygen, light, temperature)
- Knowing the smoke point will also warn you about, because of its proximity to, the
flash point and fire point. An oil reaches its flash point (about 320 degrees C (600
degrees F) for most oils) when tiny wisps of fire begin to leap from its surface.
If the oil is heated to its fire point (slightly under 400 degrees C (700 degrees
F) for most oils), its surface will be ablaze.
- Never use water to put out an oil fire: the water will splatter the burning oil and
spread it more quickly. Instead, smother the flames with a tight-fitting lid or sheet
of aluminum foil. If the fire has spread outside the pan, suffocate it with baking
soda or a fire extinguisher formulated for oil fires.
Deep-Frying With Ease
Maintain a frying temperature of 190 degrees C (375 degrees F). The batter-coated
or breaded surface will quickly form a protective shield, preventing the oil from
penetrating the cooled food and making it greasy. The food will cook by conduction
or indirect heat.
If the oil is not hot enough, oil will reach the food before the coating cooks enough
to form the protective layer. The result - greasy food.
If the oil is too hot, the coating will burn from the direct heat of the oil before
the food has had time to cook.
Dip the food in lightly beaten egg and roll in seasoned bread crumbs. Allow the uncooked
breaded food to rest on a rack at room temperature for fifteen to twenty minutes
before deep frying so the food partially dries and the crumbs adhere to the food.
Have the eggs at room temperature and avoid over beating: air bubbles are poor binders.
Small bread crumbs adhere better than large crumbs.
Avoid adding salt to food before deep-frying. The salt draws moisture to the food's
surface, which will splatter when the food is added to the hot oil. Salt also lowers
the smoke point and breaks down the oil more quickly. If required, salt can be added
just before eating.
Fry vegetable foods, like potato chips, while they are still frozen to limit the
fat absorption.
Avoid crowding the deep-fryer with food as it will lower the oil's temperature.
For each volume of food, use at least six volumes of oil.
Preheat the oil to about 7 to 8 degrees C (15 degrees F) higher than its optimal
deep-frying temperature. Preheating it higher than this may damage the oil's molecular
structure.
Signs of Deteriorated Oil
Oil darkens with use because the oil and food molecules burn when subjected to high/prolonged
heat.
The more you use an oil, the more slowly it will pour. Its viscosity changes because
of changes to the oil's molecular structure.
Loose absorbent particles accumulate as sediment at the bottom of the storage container
or are suspended in the oil.
When smoke appears on the oils' surface before the temperature reaches 190 degrees
C (375 degrees F), your oil will no longer deep-fry effectively.
If the oil has a rancid or "off" smell or if it smells like the foods you've cooked
in it, it should be discarded.
Prolonging Oil's Useful Life
The longer an oil is heated, the more quickly it will decompose. Avoid preheating
the oil any longer than necessary. If you're cooking more than one batch of food,
quickly add each new batch, unless time is needed to adjust the cooking temperature.
Turn off the heat as soon as you've removed the last food batch from the oil. Cool.
Use a quality deep-fat frying thermometer, even if you're using an electric deep
fryer.
Shake off loosely attached break crumbs from breaded food before adding the food
to the oil. Loose crumbs and other particles scorch quickly and pollute your oil.
Use a small strainer or slotted spoon to remove as many crumbs as possible.
When the oil has cooled enough that it is safe to handle, strain it through paper
towels, coffee filters or cheesecloth into its original empty container or a clear
glass jar. Do not mix it with unused oil.
Store the oil, tightly sealed, in a cool, dark place or in the refrigerator. The
oil may cloud in the refrigerator, but it should become clear again at room temperature
with no ill effects.
