Deep Fry Oil Reuse

[chef_biz]

I recently got a deep fryer for Christmas and I'm new to this technique. So far, I've mainly used it for fries, but I also made shrimp. My question is, how good is the reuse of the oil (right now it is peanut oil I believe)? It has been in the deep fryer for about 2 weeks or a little longer. Beyond taste, would it be safe to still use? It looks and smells fine. I don't want to go buy more oil if I don't really have to. Thanks

p.s. I've known it is reusable I just don't know any of the guidelines if there are any.

 

[scott123]

If you ask any nutritionist that's studied fats they will tell you to NEVER re-use oil. I don't know the exact science, but I do know that heat breaks down fat. As fat decays, free radicals are formed. These free radicals are blamed for a host of health problems including cancer.

This being said, using fresh oil every day can be expensive and not terribly practical. Impurities speed the process of decay as does air and light. I don't deep fry, but if I did, I'd pass the oil through a coffee filter before storing it. I'd also seek out extremely fresh oil to begin with and I'd utilize containers/cooking implements with as little exposure to air/light as possible.

Even taking these steps, though, I wouldn't use oil more than two or three times.

Don't think that I suffer from food phobia either. I eat plenty of smoked food, grilled food, saturated fats, eggs, butter, salt, artificial sweeteners and food grown with pesticides. You name a food that's been link with health concerns and I practically live on it. But re-using deep fryer oil indiscriminately- that I won't do.

 

[marmalady]

Gawd, Scott, I'll never eat fried food at a restaurant again, lol! The two restaurants I worked at changed their oil once a week - maybe!

That having been said, for home use, and especially with peanut oil, I think you could safely get 2-3 uses out of it, depending on what you've cooked in it. If there's a smell to the oil, (ie, does it smell 'burnt', or have a retained food smell?), or cloudiness, then I wouldn't re-use it. The main thing to remember with any oil is that heating it makes the oil drop its 'smoke point', ie the oil will come to temp and beyond much quicker, which could potentially be a danger.

 

[BigDog]

When I worked short order grill at a college I attended, the oil was filtered every night, but only changed once a week. Towards the end of the week, things got to tasting a bit odd . . . . .

 

[Aurora]

I recently got a deep fryer for Christmas and I'm new to this technique. So far, I've mainly used it for fries, but I also made shrimp. My question is, how good is the reuse of the oil (right now it is peanut oil I believe)? It has been in the deep fryer for about 2 weeks or a little longer. Beyond taste, would it be safe to still use? It looks and smells fine. I don't want to go buy more oil if I don't really have to. Thanks

p.s. I've known it is reusable I just don't know any of the guidelines if there are any.

The answer to this question will depend upon a number of factors including the type of oil that you are using, the types of foods that are cooked in the oil, the temperatures to which the oil is heated and the number of times the oil is used.

First, different oils have different smoke points. The smoke point is the temperature at which you see little wiffs of smoke begin to appear over the oil and you begin to smell a funny burnt type odor. When oil is heated there is a chemical change that begins to make the oil deteriorate. The more times an oil is heated and higher temperatures increase this chemical change and breakdown. Different types of oils have different temperatures at which they begin to smoke.

Here is a list of common cooking oils and their approximate smoke points when fresh:

[FONT=arial,helvetica,geneva]Safflower - 5[/FONT][FONT=arial,helvetica,geneva]09 degrees F - 265 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Sunflower - [/FONT][FONT=arial,helvetica,geneva]474 degrees F - 246 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Soybean - 4[/FONT][FONT=arial,helvetica,geneva]65 degrees F - 241 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Canola - [/FONT][FONT=arial,helvetica,geneva]460 degrees F - 238 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Corn - [/FONT][FONT=arial,helvetica,geneva]456 degrees F - 236 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Peanut - [/FONT][FONT=arial,helvetica,geneva]447 degrees F - 231 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Sesame - [/FONT][FONT=arial,helvetica,geneva]419 degrees F - 215 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Olive - [/FONT][FONT=arial,helvetica,geneva]374 degrees F - 190 degrees C[/FONT]
[FONT=arial,helvetica,geneva]Animal fats (tallo/lard) - [/FONT][FONT=arial,helvetica,geneva]361 to 401 degrees F - 183 to 205 degrees C[/FONT]

The smoke point is lowered each time you use the oil by chemical changes and foreign matter contamination.

The optimal deep fat frying cooking temperature is between 350 and 375 degrees F or 176 and 190 degrees C. You should never heat your oil to greater than 375 degrees F or 190 degrees C.

All that said, there are some common sense guides to let you know when a cooking oil needs to be changed:

1. Taste, smell and appearance - The oil should not taste or smell bad and should be clear and light colored. Too much breakdown and foreign matter is evident in the smell and taste of the oil and in it's color.
2. The smoke point should not be below 375 degrees F. or 190 degrees C.

As a general rule, if you watch your temperatures and keep your oil free from too much extraneous matter (batter, salt, etc.) I find that I get good results and clean tasting food if I change my cooking oil after using it between 6 and 8 times.

Addendum:

Where and how you store your oil between cooking sessions is a very important factor in the how often you can re-use cooking oil. You should strain the oil through a coffee filter after each use and store it in an air tight container in the refrigerator. Note that when the oil is cooled it may become cloudy, but it should return to being clear and see-through when brought back to room temperature and reheated.

 

[texasgirl]

I will reuse when I fry french fries, about 2-3 times, but once any meat or seafood go in, it goes out!

 

[Guts]

Ok how do you dispose of the used OIL?

BTW Good answer Aurora!

 

[texasgirl]

I use old washing detergent bottles to pour mine in and throw it away. Probably not the best way,but, there isn't anywhere around here to dispose of it properly.

 

[Aurora]

Ok how do you dispose of the used OIL?

BTW Good answer Aurora!

Thank you. I re-read my post and realized that I forgot a very important factor in the re-use of oil which I have added to my previous post and that is:

Where and how you store your oil between cooking sessions is a very important factor in the how often you can re-use cooking oil. You should strain the oil through a coffee filter after each use and store it in an air tight container in the refrigerator. Note that when the oil is cooled it may become cloudy, but it should return to being clear and see-through when brought back to room temperature and reheated.

Vegetable cooking oil is environmentally friendly and can be disposed of in your regular trash. I would not put it down the drain since it may contain components of saturated fats which could clog your pipes. This is especially important if you have a septic tank.

If you wish to be extra environmentally aware you may wish to call your local refuse company or city and find out if they have a cooking oil recycling program. There are some companies and individuals who will pick up your used cooking oils from various repositories (usually behind restaurants) for recycling as bio-diesel fuel. Always check with the recycling company or the restaurant before attempting to dump any used oil in their recycle bin.

Recycling to bio-diesel is a very simple process in which they filter the oil several times and often mix it with alchohol and/or diesel fuel to burn in a diesel engine.

 

[chef_biz]

Thank you all for the information.

It looks and smells ok but after reading some of your posts I think I will just get rid of it and get some new oil in there. One question I'm still confused on. Which is the better storage method? Some of you said to put it in the fridge. The book that came with the fryer said you could store the oil in it for later use. Which is better??

 

[Andy M.]

Keep the oil in a cool corner of the kitchen (refrigeration is not necessary) and reuse it until it tastes bad and/or smokes too soon as described above.

Oils such as safflower and canola, even though they have high smoke points, are not good choices for deep frying as they are less stable than others and will become unusable faster than corn or peanut oils.

 

[jasonr]

I don't get it, why wouldn't you just dispose of it in the sink, like expired milk?

 

[Ishbel]

It could clog up the drains and is not good for the sewage system, either.

 

[letscook]

I don't leave my oil in the fryer, I take it out after it has cooled down and pour it into mayonaise jars and store it in the refidge. I use it only 2-3 times unless seafood has been cooked in it and then it gets tossed. I take a coffee filter and a funnel and pour the oile thru it before putting it in refridege also.I also use dishsoap bottles or ketchup, and then toss in the trash. i use either peanut or canola oil