How many times can you reuse cooking oil?

Question

That is, when using a deep fat fryer to fry chips, etc what is the optimal amount of times that it should be reused before having to change it.

Answer 1

A recent study found that a toxin called 4-hydroxy-trans-2-nonenal (HNE) forms when such oils as canola, corn, soybean and sunflower oils are reheated. Consumption of foods containing HNE from cooking oils has been associated with increased risks of cardiovascular disease, stroke, Parkinson'?s disease, Alzheimer's disease, Huntington's disease, various liver disorders, and cancer. Once absorbed in the body, HNE reacts with DNA, RNA and proteins affecting basic cellular processes.

That being said, reusing cooking oil has been done for ages. There really isn't a problem, if done properly. The greatest hazard is allowing the fat to become rancid (spoiled) and deteriorated to the point it produces undesirable flavors and odors. Besides ruining what would have been a perfectly good meal, rancid oils also contain free radicals that are potentially carcinogenic. Rancid oil has fewer antioxidants but is not poisonous.

To re-use oil safely, use these tips:

Strain it through a few layers of cheesecloth to catch any food particles. Be careful with hot oil, though, because you can easily get burned.

Shake off excess batter from food before frying it.

Use a good thermometer to fry foods at 190°C.

Turn off the heat after you are done cooking. Exposing oil to prolonged heat accelerates rancidity.

Don't mix different types of oil.

Store oil in a cool, dark place.

Avoid iron or copper pots or pans for frying oil that is to be reused. These metals also accelerate rancidity.


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.

Answer 2

It really depends on what you use it for and how you store it and how often you plan on reusing it. Oil goes bad or turns rancid after a while because of air,light, and heat. If you can store it in a cool dark place after use it will last longer. Always give oil a smell before use. If it has that funny rancid smell to it toss it. I don't fry food very often so I get only a few uses out of each batch. If I fry fish or other seafood in some oil, I will only use it again for seafood. If I fry some chicken or potatoes, I will use it for egg rolls or fried wontons.

Answer 3

Restaurants reuse cooking oil all the time even the better ones do -the expensive ones probably use oil in short batches and reuse it maybe couple of times whereas greasyspoon types probably few more times in their deep fryers.. At home, I seldom fry - on the rare occasion I do, I keep a low amount in a really small pan ---I fry in coconut oil ---...this is one oil that tastes good and toasty after the initial frying... something I recall from growing up in coconut country --the remainder of this oil I use up as I cook other things...

Answer 4

I only ever reuse it for deep frying 3 times in all and in between I cool it, strain it then put it back into a bottle and seal it. It goes dark if its getting too old. Also it can give you a terrible upset stomach if you reuse it to often as it goes off.

Answer 5

As a a former chef I can say if you filter it after every use, cool it and keep in the frig, you should get 8-10 uses, but as it gets older and changes colour, it can break down, but if you add a bit of fresh oil or fat (Shortening or lard) animal fats tend to break down faster and the chance of going rancid are there to, but they do add flavour to chips, I am partial to beef fat (tallow), it is not as available in Ontario Canada were I live, but when I was living in Alberta canada, beef country it was more widely available.

Answer 6

Generally till it discolours, depends how much your cooking each time, is it just chips, heating and cooling oil doesn't do it any favours ...
when your finished with cooking you can use the oil in the diesel tank of your car once its strained.

Answer 7

I would change it after 3 to 4 times of being used, you can tell by the colour of it when it starts going dark in colour and smells stronger each time you have used it.

Answer 8

I use sunflower oil. On the label it recommends changing after 8 uses.

Answer 9

In the event that it's a fruit it includes seeds, otherwise it's a vegetable. And vegetables are usually grown in the ground while fruits are grown in trees.

Answer 10

Lots of interesting answers to consider! My 2 cents: ONCE if you cook meat in it. 3 times if you cook potatoes.