COOKING OIL: Important Facts to Know
Since early times when human civilization first developed pots a
nd pans, people have used various forms of cooking oil for frying.
Originally animal fat (grease/lard) was used for frying which now is mostly replaced by olive, vegetable and peanut oil.
It is almost universal knowledge that over-heated cooking oil will catch fire and burn. Cooking oil has a flashpoint temperature
ranging from 550˚F to 700˚F, depending on type of oil used, altitude and ambient temperature. However, most people do
not realize that cooking oil typically does not burn when below its flashpoint temperature.
Cooking oil contained inside the confines of a stockpot, skillet or pan (vessel) is quite stable when below its flashpoint temperature.
For example, heated cooking oil at optimum frying range of 325˚F to 350˚F does not catch fire even if a flame is accidentally
placed in contact with the oil. This stable characteristic enables cooking oil to be used on kitchen stoves inside hundreds of
millions of homes worldwide. Imagine someone smoking while frying at 350˚F and the cigarette falls into the hot oil.
The fire inside the cigarette will be extinguished by hot 350˚F cooking oil very similar had it fallen into water.
On the other side, cooking oil must be respected and used responsibly. As cooking oil is heated up approaching flashpoint
temperature, it becomes unstable and begins to breakdown. As cooking oil breaks down, vapors are created
that when mixed
with oxygen, will burn. When heated to very high temperatures, cooking oil vapors will self-ignite.
The following is a typical scenario of what happens as vegetable oil, contained in a cooking vessel, reaches its flashpoint
temperature and self ignites:
• The oil first becomes darker and emits an unpleasant odor.
• At about 440˚F, the oil begins emitting a pale vapor smoke.
• At about 500˚F, the smoke turns black.
• Soon a heavy, thick black smoke belches out.
• At about 600˚F, a small flame flickers out from the oil. At this point the cooking oil has reached its point of self-ignition.
• If the heat source below the vessel remains engaged, the flame will quickly grow.
• All the while cooking oil burns, thick black smoke continues to belch forth.
Another point many people do not know is that over-heated cooking oil that catches fire can make a huge flame.
For example, a small 12" skillet with only 1/2" deep of cooking oil can create a flame 7- ft to 9- ft high! A large cooking
vessel containing up to 3 gallons of cooking oil can create a flame up to 15- ft high!
On average, every year in the U.S. there are 80,000 kitchen/house fires caused by burning cooking oil that are responded
to by a Fire Department. Imagine a 3- ft high kitchen stove supporting a cooking vessel emitting a 7- ft flame… that is a
dangerous house fire!
The vast majority of these kitchen fires are the result of leaving cooking oil unattended. Simply answering the door bell, phone
or tending to a crying child are sufficient distractions that allow a 12" skillet with 1/2" cooking oil to over-heat and catch fire.
Eventually, burning cooking oil will self extinguish. Actual burn out time does vary but on average:
• A 12" skillet with 1/2" deep cooking oil will self extinguish in about 5 - 7 minutes after first flame emits.
• A cooking vessel with 3- gallons of cooking oil will self extinguish in about 20 - 25 minutes after first flame emits.
Either way a very large flame is raging long enough to spread fire to any combustible structure that it touches.
Another well known point is that cooking oil can be re-used. Most cooking oil brands recommend using oil 4 - 5 times if it is
strained, and can be stored in a cool dark place from 9 - 12 months.
During the storage period bacteria will form on poultry, fish or animal fats remaining in the oil. This bacteria is quickly killed
when the oil is re-heated. Prior to using again, it is recommended that you smell the cooking oil. If it smells unpleasant or
rancid, discard properly and use new cooking oil.
However, most people are unaware that used cooking oil has a reduced Smoke Point and Flash Point temperature due to partial
breakdown of the oil. (Partial break-down is caused by previous use and bacteria) Although safe for normal use, this is just
another reason to never, ever leave cooking oil unattended during heat up and cooking.
Cooking Oil facts to Remember:
• 100% Peanut Oil is considered a very stable cooking oil having a higher Smoke and Flash Point temperature than other
• Some cooking oil is sold as a "blend" of vegetable and peanut oil.
• Re-used Vegetable and Peanut Oil both have reduced Smoke and Flash Point temperatures.
• As a result, Flash Point temperature of cooking oil ranges from 550˚F to 700˚F.
Remember; Think Safety and use Common Sense when frying with cooking oil/grease.