Temperatures & Oils for Deep Frying (튀김)

Types of Oil for Deep Frying

The best kind of oil to use for deep frying is a neutral flavored oil with a high smoke point. The smoke point is the temperature at which oil will start to burn, which makes eating food from that oil unhealthy because of the chemicals released and the bitter flavor. To further elaborate on the term smoke point. It basically means the point at which the oil begins to smoke and break down.

Most ingredients are fried at roughly 350-375F, so you need an oil that can withstand that temp.

Oils that are safe to use for deep frying:

Here are the oils and their smoke points. Remember, over 400F is best for safely deep frying.

• Refined Sunflower Oil: 410-425F/210-220C
• Soybean Oil: 450F/230C
• Refined Corn Oil: 450F/230C
• Canola Oil: 425F/220C (this oil can smell at high heat because of acid)
• Peanut Oil: 424F/220C

What You Should & Shouldn’t Do to Your Oil in And Out Of The Fryer

There are some basic things that you should and shouldn’t do to your oil in and out of the fryer.

When you are deep frying, avoid this:

• If you want to keep your oil fresher longer and avoid it deteriorating, do not salt or season your ingredients over the oil. Salt will break down the oil.
• For your own safety, always make sure that the strainer and thongs that you are using are dry or the water on them will pop once they touch the oil. It can hurt, so be careful. Also, avoid having drinks or liquids near oil. In general, liquids near hot oil can be really unsafe.

Saving and Reusing your Oil:

When you use oil for deep-frying, you do not need to throw it away after one use. Oils can be reused, which saves money, but it also actually makes the food fried in that oil more flavorful.

After you let your oil completely cool 100% after deep frying, you can strain the oil into an airtight container. An airtight container is important because exposure to oxygen will make your oil go bad quicker. When reusing oil, add some fresh oil to the storage container along with the old oil. Adding some fresh oil to the old oil extends the shelf life of the used oil. Once you are done with all that, you should store it in a cool, dry area.

After you have reused your oil a few times, it may be time to throw out that oil. After about 3 reuses of that oil, give it a check.

Here are some ways you can know it’s time to chuck the oil.

• If the oil is very brown, then chuck it.
• If the oil has a strong flavor of what you have deep fried it in then throw it away. For instance, if your potatoes taste like fish because you fried fish in that oil a couple of times, then throw the oil away.
• You may even see that the oil isn’t frying the food well and making it brown too quickly. This is another sign that it is time to throw away your oil.

The Temperature of Oil for Deep Frying

Now let’s move on to the temperature of the oil. Most foods are fried at around 350-375F.

When frying, you may be nervous about controlling the temperature of the oil. If the oil temperature is too low, then the ingredient will get soggy and absorb more oil which will not allow a crisp crust. If the oil temperature is too hot, then the oil will start to break down, and the outside of your ingredients will brown or burn before the center of the ingredient is fully cooked.

Testing the Temperature without a Thermometer:

If you have heated your oil and want to test if it is ready. You can drip some of your frying batter into the oil. If it immediately floats and starts to bubble a lot, then the oil may be too hot. The ingredient (or in this case, the trial drip of batter) should sink into the lower middle of the oil and then, after a few seconds, rise to the surface with small bubbles surrounding it.

You also need to monitor the color of the trial drip of batter. Watch and see how quickly that drop of batter browns. If it turns brown immediately, then the same thing will happen to your ingredient.

Double Frying:

There is a deep-frying method called double frying. The basic idea is to fry an ingredient first at a low temperature until the ingredient is 95% done, then fry again at a higher temperature to crisp the surface of the ingredient. In between the first and second fry, scoop out any particles so that those little pieces do not stick to your ingredient.

There is a science as to why this is done, but to simplify, the reason double frying is done is that in the first lower temperature fry, moisture is removed from the ingredient. Because there is less moisture when we fry the ingredient again at a higher temperature, the surface of the ingredient can get very crispy.

Some ingredients are worth taking the effort to double fry. I think that pork and chicken are great for that. I wouldn’t recommend double frying for delicate ingredients like squid or octopus that are usually completely cooked within a few minutes because they could become chewy.

Double Frying Temperature:

First Fry: 300-330F

Second Fry: 350-360F

Basic Frying Temperature for Common Ingredients:

• Fried Fish: 350-375F
• Fried Chicken: Double Fry
• Fried Vegetables: 325-340F
• Fried Seafood: 340F
• Fried Pork: Double Fry

Deep Frying Tips & Safety

1. When adding an ingredient to hot oil, you do not want to plop the ingredient into the oil. Instead, hold the ingredient and gently place it away from yourself into the oil. It should not drop; it should gently lay into the oil. 
2. Gradually add ingredients to the oil to avoid a sudden drop in temperature. Do not overload your deep fryer. If you overload your deep fryer, then the oil temperature will drop and make your ingredients soggy. Always deep fry in smaller batches.
3. Use a dry metal strainer to lift the ingredients out of the oil and into the air. Do this every so often as the ingredient fries. The exposure to the air further crisps up the outside of the ingredient.
4. Use a strainer to collect and remove the ingredients from the oil once they are fully cooked. In between batches of fried ingredients, you want to remove the small pieces of batter that remain in the oil. These little pieces can burn and stick to your fried ingredients if not removed in between batches.
5. Use a strainer to let the ingredients drain of oil after they are done frying and before serving to avoid the ingredients from getting soggy.

How to Throw Away Oil

1. Let the oil cool completely. You can let it cool in the deep fryer or pan, or you can carefully pour it into a metal bowl to let it cool.
2. After letting it cool, you want to place the oil into a bar or container. It is better to avoid pouring it into your trash can directly because it can leak. You can pour the oil into an old milk container and then place it in a disposable bag. If you don’t have a container, just pour the oil into a separate bag and then place it in the trash. Never pour down the drain or down the toilet.

What to do if you spill oil

If you ever spill a lot of oil on the floor, then pour salt all over the oil. You want to be generous with the amount of salt you pour over the oil. The salt will help absorb and pick up the oil. Then you can just use a rag and scoop up the salty oil.