Punchinello's Chronicles

August 31, 2010

Using Oil for Deep Frying

People think that deep-fried foods are unhealthy. It’s greasy, they say, loaded with fat or loaded with cholesterol. People say all kinds of things that aren’t true, but if enough people say something stupid then people start to think it’s true anyway. The fact is that deep-frying food is fine as long as you know a little about what you’re doing. The problem is what to do about the used oil.

For years I tended to avoid frying things like chicken or potatoes in a deep fryer because I couldn’t figure out how to re-use the oil. Depending on what you’re cooking, you might use only 1-2 cups of oil, or you might use 4 cups of oil. Even though oil isn’t all that expensive, I just didn’t like the idea of using all that cooking oil once then throwing it away. Of course the solution would be to strain and clean the oil, but that took forever.

The Right Way to Deep Fry

First of all, that alleged “greasy” reputation wrongly given to Chinese food is usually sesame oil. It’s there on purpose, in the same way that you have an oil and vinaigrette dressing on a salad. You wouldn’t turn up your nose and say that a salad is greasy, right?

Secondly, most people think they’re getting the right temperature when they use their stove to fry something in oil. In almost all cases, stove-top burners at home don’t have enough energy to keep frying oil at 350° much less the 375° you’ll want for crispy, non-oily chicken or fish. Use a frying thermometer and watch how quickly you lose heat when you add in the food. Then see how it barely creeps back to 325°, even on the high setting.

  • Commercial stoves and deep fryers produce more BTUs of energy than home appliances.
  • A home appliance fryer should have the capability to reach 400“ in order to sustain 375° during the frying process (more likely 350°, which is fine, but 375° is crispier).

Deep frying in a coating, or particularly in a batter is a unique way to preserve moisture in food. The high temperature of the hot oil instantly cauterizes that outer batter. That creates an air-tight seal around the food, trapping the juices and many nutrients inside the food. The result is moist, juicy and very flavorful.

  • One symptom of wrongly cooked fried food is that it’s dry.
  • Another symptom is that there’s a lot of oil when you place the food on a paper towel or drain rack.
  • Other than letting some oil drip off the food as you remove it from the oil, there should be very little oil on the plate or in your mouth.

Incorrect frying does two things. First, it doesn’t seal the outer coating, allowing water and steam to escape. That leads to sputtering and popping, and a very loud “sizzle” sound. People think that’s a good thing. No, it’s a bad thing! Secondly, because it’s taking too long to seal the batter, oil seeps into the coating leaving a lot of oil and grease on the final product.

To instantly seal off the food and batter, the oil has to be at the proper temperature. That’s the problem, because inexpensive electric fryers almost immediately lose anywhere from 50-100 degrees of oil temperature when you put in the food.

  • Always have your food as dry as possible, just prior to putting it into the oil.
  • Bring the food to room temperature prior to frying, but don’t let it sit around warm (particularly for chicken)

It’s easy, really. All you have to do is take the food out of the fridge an hour or so before you’re ready to fry it. Since it takes around 15 minutes to bring oil to the right temperature, and you’re often preparing a batter or coating, you’re really only talking about half an hour ahead of time to remove the food from the fridge.

Chicken doesn’t magically “catch” salmonellae out of the blue! Most chicken is pretty clean, what with FDA inspections and so forth. If it’s clean and purchased from a reputable store, and it isn’t past the expiration date, then you don’t have to treat chicken like it’s a hazardous material! There’s no problem at all with allowing it to warm to room temperature, just prior to cooking.

Plus, bacteria is killed when it’s subjected to high heat. That’s why cooking food is a good thing!

Steam is the Enemy

Have you ever deep fried chicken in a batter, then had the coating slide off the food when you go to eat it? The bond between the batter or coating, and the food was broken by steam. The juices in the food almost instantly become super-heated when the food enters the oil, producing a miniature explosion. That pushes the batter/coating away from the surface of the food.

To prevent this from happening, you want your food to be as dry as possible on the surface, prior to coating it with a batter.

  • To fry vegetables (e.g., eggplant, onion rings, etc.) dredge in flour and let sit prior to coating with batter.
  • Lightly coat meat, fish or poultry with a bit of flour prior to dipping in batter.
  • Pack moist fillings tightly, as in egg rolls or wontons prior to frying.

When it comes to egg rolls, which use cooked cabbage and have some moisture, the trick is to pack the filling tightly in the skins. In this case, the problem becomes steam build-up inside the egg roll. That puffs the skin away from the filling, leading to soggy egg rolls. I tend to pan-fry egg rolls rather than deep fry them, to allow steam to escape from the top, which isn’t covered in oil.

Best Way to Clean Frying Oil

A lot of Asian food involves deep frying, so once again, as I started learning how to replicate Chinese restaurant dishes I needed a way to work with oil. Many people use cheesecloth, but that’s expensive if you use it regularly. Other people use coffee filters, but that’ll sit overnight most of the time. Then there are home appliance units that will strain the oil, and that also takes hours and hours.

I ran across a post, somewhere:

  • Use a plain paper towel in a regular household strainer to clean and recover used oil. Perfect!

This trick works best with the oil a little bit warm, maybe around 225-degrees, but I’ve found that it works just as well when the oil is room temperature. Just put a paper towel in a regular strainer, lay the strainer over a deep bowl, then pour the oil into the strainer. It drains very quickly and filters out all but the tiniest particles. The result is easily re-usable, and you’re done in minutes instead of hours!

  • Store used oil in an air-tight container. It’s the air that causes oil to go rancid, like oxygen causes rust on metal.

How Many Times Can You Use Oil?

Each time you fry with the same oil, the smoke point goes lower. This is the point at which the oil begins to burn. The smoke point temperature is used to measure the capabilities of different types of oil. The lower the degree, the more delicate is the oil. The higher the smoke point, the better it will handle high-temperature frying.

Vegetable oil and peanut oil both have high smoke points, and can easily tolerate the 375° F temperatures used in typical frying. The other typical temperature is 350° F, which is still too high for things like olive oil. That’s not to say that you can’t use olive oil in a pan for pan-fried this or that, you just don’t use olive oil for deep-fried chicken.

The oil begins to break down under high temperatures, so when it cools it tends to have a lower smoke point. That being said, you can usually use the same oil about 4-5 times. You’ll see the oil get darker, depending on what you’re frying, and you’ll eventually notice an odor of burning oil.

If you’re frying something that doesn’t produce small particles, for example potatoes or vegetables, the oil will remain mostly clear. That you can certainly use 4-5 times. On the other hand, if you fry chicken with a batter or flour coating, then you’ll probably only get away with 2-3 times.

Something else to consider: French fries. When you buy fries at a fast-food place, they’ve been using the oil many times during the day. The flavor that blends into the hot oil then transfers back to the fried food. Used oil is often better for fries than clean oil. You get better browning, and you get additional flavor.

You probably wouldn’t want to use oil in which you’ve fried fish to then fry vegetables. Nor would you fry shrimp, then fry chicken in the same oil. Depends on your taste buds, but remember there’ll be some transfer of flavor from different types of foods. That’s not always a bad thing. In some cases it’s a good thing!

Don’t add a lot of new oil to previously used oil. Some is okay, but no more than about half the existing volume. The used oil lowers the smoke point of the new oil.

  • Don’t mix two different kinds of oil when deep frying. So don’t have some leftover vegetable oil, then toss in some olive oil just because you want to finish off a bottle.

What Kind of OIl?

Because of all this health stuff that’s been going around, a lot of people think that Canola oil is very healthy for you. Indeed, it actually is pretty good when used cold, like for salad dressing. But under high heat, canola oil not only breaks down, its physical properties begin to change. You end up with a lot of trans fats and hydrogenated oil, none of which is healthy or good for you. There’s also the unexamined aspect that we’re seeing more genetically modified canola, and we don’t really know the long-term problems that might be related.

The two best kinds of oil to use are regular vegetable oil or peanut oil. Plain corn oil is decent as well, but the cost of vegetable oil makes it practical. Many people think that all Chinese frying is done with peanut oil. It isn’t. More often than not, it’s vegetable oil.

Peanut oil has a distinct flavor, which of course transfers to the food. If you can afford it, then peanut oil works very well for egg rolls, fried shrimp, or wontons. It’s also excellent for Swiss fondues. But when you’re just frying something for crispiness, like fried pork for sweet-and-sour pork, don’t bother. The oil flavor will be lost in the sauces, so vegetable oil is the most cost effective.

Disposing of Old Oil

You don’t want to throw old cooking oil down your drain. It gunks up the pipes, puts a coating on everything, eventually goes rancid and starts to smell. So what do you do with it? If you just toss 3 cups of oil in your trash bag, it leaks everywhere and makes a mess.

As you get more interested in deep frying, reclaiming oil and using it more than one time, you’ll probably start buying oil in gallon jugs. It’s inexpensive (vegetable oil), doesn’t take all that much room, and you easily can fry all sorts of things. Just keep the empty jug. It has a cap, it’s heavy plastic, and you can pour old oil into the empty jug until it’s full. Then throw away the jug (with the cap screwed on nicely).

Alright, but what do you do with the oil you want to toss BEFORE you have the empty jug? Zip-Loc bags! Even with a large fryer and a whole chicken, you likely won’t use more than about 3-4 cups of oil. And remember, you’ll be cleaning that oil then using some of it for smaller frying jobs. When you’re done, take a 1-quart zipper-type plastic bag and rest it in a bowl.

The reason for resting it in the bowl is to support the sides as you pour in the old oil. Zip it up and toss it in the trash. Easy and clean. Another option is to save a couple of old mayonnaise jars, bottled water containers, soda jugs or any other container with a re-closeable top. Use a funnel, pour the old oil in the bottle or container, and toss. We happen to like Planter’s peanuts, so we keep those containers. They’ll hold 2 cups of oil, which is just what you want to fry chicken in a pan.

Tip — Washing the Dishes

All-purpose kitchen cleaner, engine degreaserOne of the best all-around household cleaners I’ve found is Castrol SuperClean. It’s an automotive degreaser, and it works superbly for the kitchen and just about anything else that’s hard to clean. It particularly removes built-up cigarette smoke residue from things like plastic, glass, computer cases and closet doors. Venetian blinds, mini-blinds, stove-tops: Stuff like that. It also makes cleaning up frying oil very simple.

The nice thing about a degreaser is that it dissolves oil on contact. Wipe out a frying pan, spray some of this on the pan, then wash it. (I don’t have a dishwasher, and have to do dishes by hand.) For deep fryers that won’t safely go into an automatic dishwasher, this will clean out the inside. Then you can put a dab of dish liquid in there, some water, wash it and rinse, and you’re done.

You can buy the spray bottle, and usually the 1-gallon refills at many hardware stores (we have Ace Hardware around here). It’s also available at Wal-Mart and many automotive supply stores. Look in the automotive section for the purple container. A little goes a long way, so it’s worth the money!


Use a good quality, absorbent paper towel to make life tremendously more enjoyable when it comes to straining oil for using it again. Recovering oil after frying makes it a whole lot more cost effective to enjoy deep fried foods.

A nice shortening to use for pan frying is regular Crisco. The way that’s manufactured, you get a clean oil when it’s melted, without the bad chemistry. Additionally, when it cools down again it re-solidifies, making it easier to wipe out a pan before washing. Crisco works for pan-fried chicken and food, not for deep frying.

You only need enough oil to float whatever it is you’re frying. So about two times the height of your food. The food should have a bit of room around it, so either use a larger pot or fry less food in each batch.

Finally, a note about butter. It’s WAY healthier for you than margarine! When you examine all the byproducts of margarine, you’ll discover that it’s killing you. Take some time to consider who in particular has been promoting the use of margarine over butter all these past decades. Then do some research on butter. If you continue to margarine or “butter-like spreads,” you’re being very foolish.

Related – Table of Contents for Chinese Take-out



  1. […] More here: Using Oil for Deep Frying « Punchinello's Chronicles […]

    Pingback by Using Oil for Deep Frying « Punchinello's Chronicles | ClubEvoo — September 1, 2010 @ 12:56 am | Reply

  2. is there any way to save vegetable oil for burning while deep frying in bulk quantity on high temprature

    Comment by Anwar — July 3, 2012 @ 3:51 pm | Reply

    • Vegetable, corn, soy, peanut, safflower: Any oil can be strained and stored in any quantity for one or two times, as long as you have a large enough storage container. The issue is how many times have you used the oil. Each time you use it, the “smoke point” gets lower. That’s the temperature at which the oil begins to smoke. Typical frying is at 300 – 350F degrees. If the smoke point is below that, then you get a negative taste.

      If you are using a gallon of oil in a commercial fryer, this entire post doesn’t really apply. Those machines already have storage instructions and capabilities. However, for home use you can use a paper towel in a strainer over a large container and quickly remove food particles. Store the oil in an air-tight container to prevent it going rancid. I use an old V8 tomato juice plastic bottle, then use the “used” oil for other things like frying chicken or whenever I need some oil in a pan. When I do more deep frying, I use the previous oil first.

      When you mix new oil and previously used oil, the overall smoke point is lowered. Also, you’ll pick up some of the taste of whatever food was fried previously. For me, it’s not an issue, but some people don’t like to mix the taste of fried fish with vegetables. Note that canola oil is really bad for you if you use it for frying, as it breaks down into unhealthy chemicals when heated.

      Comment by Punchinello — July 7, 2012 @ 2:23 am | Reply

  3. Is it ok to add a little bit of vegetable oil to my peanut oil for deep frying my chicken strips? I’m a little short of the amount of peanut oil I need

    Comment by stacy — February 3, 2013 @ 2:13 pm | Reply

    • You can easily mix and combine oils for frying foods. The only thing I’ve been able to see that might cause a problem is different smoke points. That being said, I routinely mix a combination of corn oil, peanut oil and sunflower oil. They all seem to work just fine at 350-degrees, and I filter the oil when I’m done and use it again. The flavor is very nice, to the point where I can actually taste the difference! It’s like using cottonseed oil to fry chicken — you can definitely notice the difference.

      Comment by Punchinello — February 27, 2013 @ 2:59 pm | Reply

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