When to toss deep fryer oil?

My Hubby got me a "family deep fryer". I bought a big jug of Crisco vegetable oil and we have had it in there for about 3 days. We have only fried mozz cheese sticks so far. When do I have to toss it so we don't get sick?

I've always strained my oil when cool through a coffee filter then refridgerated what was left until the next use. I have no idea how long it lasts....but another forum has some advice. It seems to depend on a variety of factors.

HI,

I read with interest the oil smoking being an indicator for oil gone bad. Smoking oil is on the verge of turning quickly into a fire. You may want to consult this website for smoke points of various oils and what to avoid. Knowing this will also help you prolong the oil's useful life.

Regards,

Personally, I do not think that older oil will make you sick. I would agree that straining the oil keeps it a lot cleaner and will extend it longer.

Cathy2 is right. Smoking and bubbling oil indicates that the oil is at the end of its life and should be replaced soon.

In a commercial kitchen, we might keep the same oil for five days to three weeks depending on 1) the quantity of food fried in the oil and 2) what was cooked in the oil. We would always use the OLDER oil for frying fish (after which, we would dump it). If you are frying something like chicken, it is critical that you strain the oil each time as sentiment settles at the bottom of the fryer.

Hope that helps.

We have fried twice for a total of about 20 mozzarella sticks.

Believe it or not, there is no "hard and fast rule" about how many times one can re-use frying oil. One of the reasons for that is that it depends on what and how one used the oil. If the oil was heated too hot, for instance, it can cause it to break down and spoil too soon.

The "wikibooks" website indicates:
--Change the oil when it becomes extremely dark.
--A rule of thumb is to change oil each week under heavy use, or every three weeks if it's only used for frying vegetables.
--When using new oil in your fryer, add an extra 1.5 minutes to your frying time.
--Opinions differ regarding the storage of used frying oil. Those who reuse oil disagree as to whether refrigeration is necessary, but generally agree that it is important to filter the oil and then store it tightly capped and away from light. Discard reused oil when it becomes dark or begins to smell "off".
--When reusing oil, add some fresh oil for each use in order to extend its usefulness.
--Oil can be purified by deep-frying parsley. The parsley absorbs the odors in the oil.

Another website (culinary-yours) says "Knowing the smoke point can also save you money, because each time you deep-fry, you lower its smoke point irreversibly. If you want to save money by reusing an oil as many times as possible, select one with a high smoke point."

"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.
--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.

What are the best types of oils to use and what is their optimum max temperature? How much parsley needs to used to clean out smells?

I have always heard and used peanut oil for frying as it supposedly had one of the highest tolerance for heat and lasted the longest. But this from the culinary-yours website seems to put that in question:

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


Sorry the temperature is in Celsius and not Fahrenheit and I don't have any further information on the use of parsley to aid in cleansing the oil. 160-190 degrees Celsius, however, is equal to 325-375 degrees Fahrenheit.

One more issue. Use a thermometer to test the thermostat on your fryer (especially a commercial one). If you get the oil too hot (which might happen in an older fryer), you run greater risk of fire.

jlawrence01 wrote:One more issue. Use a thermometer to test the thermostat on your fryer (especially a commercial one). If you get the oil too hot (which might happen in an older fryer), you run greater risk of fire.

I once had a fire from overheated oil, which ignited very fast. It is for that reason I now put the fryer in my stainless steel sink with baking soda available to help stop any incident. A fitted lid, which can be slid on from an edge will remove the oxygen to also quench the fire.

Regards,

Here is another bit of information on smoke points of oil in Fahrenheit temperature:

Type of oil Smoke Point °F
avocado (mono) 510
safflower oil (poly) 460
soybean oil (poly) 450
low-erucic acid rapeseed (LEAR, or canola) oil (mono) 440
sunflower oil (poly) 440
groundnut fruit (peanut) oil (mono) 440
grape seed oil 420
cottonseed oil (poly) 420
corn oil (poly) 420
sesameseed oil 390
lard (sat) 380
shortening 363
olive oil (mono) 200-406
butter (sat) 350
coconut oil (sat) 350
hemp seed oil 330
flaxseed oil 225
palm kernel oil (sat) ?
palm oil (sat) ?
cream (sat) ?
suet (beef fat) (sat) ?
poultry fat (sat) ?
cocoa butter (sat) ?
margarine (sat) ?

"The smoke point of an oil or fat is the temperature at which it gives off smoke. When oil is smoking, it gives off bad fumes and is could be prone to bursting into flame. Flames from a pot of burning oil will reach up for 2 or 3 feet. The smoke point of an oil should be high when the oil is used for deep-fat frying or when it will be exposed alone on surfaces such as cookie sheets. The numbers here are common values; oils will vary.

Olive oil is particularly variable; higher quality cold-pressed grades have lower smoke points than cheaper solvent-extracted and refined grades. It is better not to use high-quality olive oil for deep frying—save it for your salads."

The flash point for these oils are a bit higher (maybe not too much higher), but I don't want to minimize the caution that all should take when using them. I will try to post later those temperature flash points when I can locate them. Most newer immersion deep fryers now limit the temperature to 375 degrees F.

When oil is smoking, it gives off bad fumes and is could be prone to bursting into flame.

I remember this practical application from junior high school: extinguish a candle, then take a flaming match to the smoke trail. The smoke + the flaming match will cause the candle wick to reignite. Of course, I am not talking some feet away but certainly inches.

Now consider how close your stove's gas flame is to igniting smoking oil. Of course it does not need that flame, it can spontaneously combust.

Having been present at several grease fires, I am cautious.

Regards,

Cathy2 wrote:Having been present at several grease fires, I am cautious.

I had a couple of roommates in college that loved to deep fry food. One of them set the apartment on fire when she put the oil on to fry and went upstairs to brush her teeth. (Hey,she was in college and it was Saturday night.) I was somewhere else at the time and when I went back to investigate the damage, there was--literally--a black hole where the kitchen had been.

Luckily no-one was hurt.

grits wrote:I was somewhere else at the time and when I went back to investigate the damage, there was--literally--a black hole where the kitchen had been.

You shoulda whipped your cellphone out and said "Scotty, beam me out fast, there's a black hole here!"