Deep fryers cook food by transferring heat from hot oil to its surface and then into its center. Some moisture turns to steam, producing bubbles. Bubbling and browning do not prove that the center is cooked; follow the recipe or package and check the safe internal temperature where required.
While this is how all deep fryers operate, there may be slight differences according to the type of deep fryer.
Types Of Deep Fryers
We can broadly classify deep fryers as gas and electric. Apart from this classification, we can also divide deep fryers based on their structure into the following.
Tube-Style Deep Fryers
These deep fryers have heating tubes running along their base. When the heating tank is heated, the tubes transfer heat to the oil.
Beneath the tubes is a sediment area. All the crumbs, burnt food, and other residue settle into this area during the frying process. Separating crumbs from the hottest area can reduce burning, but the oil still needs regular inspection and replacement.
Cleaning access depends on the model. Follow its instructions and let the oil and appliance cool completely before cleaning around heating tubes.
Open-Pot Deep Fryers
The heating element is wrapped around the base on the exterior of the tank in these deep fryers. They can run on electricity or gas.
When the base of the deep fryer becomes heated, the oil in the pot will also become warm.
Additionally, there is a sediment zone at the bottom of the deep fryer to catch all the burnt bits.
Open-pot deep fryers usually hold large amounts of oil, making it easy to cook a big batch of food at once.
Flat-Bottom Deep Fryer
As the name suggests, flat-bottom deep fryers have a flat bottom. There is no separate area for the heating tubes, they are directly connected to the base.
So, the leftover food particles settle out of the hot oil. This type of deep fryer is best suited for bulk frying of chips and other smaller ingredients.
Pressure Fryers
Pressure fryers are generally used for commercial cooking. Their distinguishing feature is controlled pressure in a purpose-built sealed chamber.
Purpose-built pressure fryers use a sealed cooking chamber and controlled pressure. They are not ordinary pressure cookers: never try deep-frying under pressure in a household pressure cooker or multicooker unless it is specifically designed and approved for pressure frying.
Parts of A Deep Fryer
Most deep fryers will be made of stainless steel. Let’s look at the other parts of this appliance.
Heating Element
The heating element is usually in the base of a deep fryer. It’s usually in direct contact with the oil and transfers heat to the oil.
Oil Reservoir
The oil reservoir is the big pan that holds the cooking oil. As we mentioned earlier, it’s typically constructed with stainless steel.
The oil reservoir should be deep enough to fully immerse the food items during cooking. It should also not be overfilled to prevent spilling and accidents.
Frying Basket
The frying basket allows you to lower the cooking ingredient into the oil without directly dropping it into the oil.
When the food is lowered into the oil, bubbles appear around it. When it’s done, you can easily lift the basket with the cooked food.
It’s much easier than having to fish out the cooked food after frying.
Electronic Components
Electric deep fryers will have several electric and electronic components. This includes:
- A control panel with buttons or dials to adjust the temperature, set the cooking time, and other cooking functions.
- The thermostat cycles the heat to regulate the selected temperature. It does not remove the need to supervise the fryer.
- Overheating protection circuits act as safety features to prevent accidents and fires due to overheating of the oil.
Lid
Lid use depends on the fryer and the food. For example, the Presto ProFry LE instructions say to leave its cover off when frying raw fries and other high-moisture foods. Follow your own model manual.
Follow the model’s instructions rather than adding a cover to control splattering; trapped steam can create a hazard.
Oil Drainage System and Sediment Tray
Deep fryers hold large amounts of oil. However, you may not need so much oil to fry a single batch of food.
But burnt food or crumbs in the oil will contaminate the oil that remains, reducing its quality.
To prevent this, advanced deep fryers usually have an oil drainage system and sediment tray. They catch and separate the food residue from the oil, making it convenient to reuse the oil.
Depending on the make and model, deep fryers may also have other parts like a viewing window, cool-touch handles, and automatic shut-off controls for safe operation.
How Do Deep Fryers Operate?
Deep frying is a process in which the food is cooked in hot oil at a temperature of 325°F to 400°F.
At this temperature, the food cooks and develops a crispy exterior. Technically, there are four phases to this process.
- Heating: When you switch on or apply heat to the deep fryer, the oil in the container starts heating up. Once the oil reaches the right temperature, you can add the food into the basket and place it in the oil. The sudden exposure to heat will immediately cook the exterior surface of the food. Meanwhile, the insides are still uncooked. The surface gradually dries and browns while heat continues moving inward; the crust does not form a waterproof seal.
- Surface Boiling: During the second phase, the oil is still hot, which causes the moisture inside the uncooked food to vaporize. Heat from the oil moves through the food as some of its water evaporates. You will notice bubbles at the food surface during this time. They are formed when the evaporating water touches the hot oil. Bubbles show steam leaving the food, but they do not show its internal temperature or prevent all oil absorption.
- Moisture Loss: As frying continues, some moisture leaves the food and bubbling may become less vigorous. This is not a doneness test.
- Checking Doneness: Use the recommended cooking method and a food thermometer for meat, poultry and seafood. FoodSafety.gov lists 165°F for poultry and 145°F for fin fish. Food can remain moist inside when it is properly cooked, so do not wait for every bubble to disappear.
Step-by-Step Process to Use a Deep Fryer
Use the following overview alongside the complete instructions for your model. It does not replace the manual.
1. Choose the Right Type of Oil
A deep fryer uses high heat. Hence, it’s ideal to use cooking oils with a high smoking point to prevent them from breaking down during deep frying.
Choose a cooking oil approved by the fryer’s manual. Ordinary butter and margarine are unsuitable for many deep fryers, and some models prohibit all solid fats.
However, oils like peanut oil and coconut oil can impart their flavor to the cooked ingredients.
Once you choose the correct oil, add it to the oil reservoir before turning on the heat. This will prevent it from splashing and causing burns.
Fill the reservoir between the model’s minimum and maximum oil marks. Leave the required space for food displacement; a generic two-thirds rule does not replace those marks.
2. Turn on The Deep Fryer
Follow the model instructions to switch on the fryer and select the temperature required by the recipe or package.
For a gas-powered fryer, follow its ignition and temperature-control instructions. A countertop electric fryer must never be placed on a stove burner.
Use the lid during preheating only as directed by the fryer’s manual.
3. Check the Temperature
Choose the oil temperature specified by the recipe or package and permitted by the fryer manual. A thermostat regulates the selected setting; it does not impose one universal limit for every food or appliance.
You can also use an oil thermometer to test the temperature.
If the oil starts smoking, turn off the heat if you can do so safely and let it cool. Do not add food, water or fresh oil to smoking oil, and do not move the hot fryer.
4. Drop the Food Into the Basket and Immerse It in The Deep Fryer
Once the oil is hot, you can deep fry the prepared food. However, moisture on the food surface can make the oil splatter and splutter.
To prevent this, pat the food dry before putting it in the oil. Dab it with a kitchen towel before placing the ingredients in the food basket and lowering it into the oil.
The food will start bubbling on all sides. These bubbles are caused by the moisture in the food that evaporates.
The hot oil heats the surface, and heat then moves toward the center. The surface dries into a crust while the interior may remain moist.
5. Check Browning and Internal Temperature
When food is deep-fried, its surface heats first. Browning can happen before the center reaches a safe temperature, especially with thick or frozen pieces.
The crust browns during the cooking process and becomes golden brown over time.
Use the recipe or package instructions to guide cooking, then check doneness:
- Browning helps you judge texture, but it is not a food-safety test.
- Check the safe internal temperature with a clean food thermometer for meat, poultry and seafood.
Lift the food carefully to check it; if the center is not ready, return it to the oil using the fryer’s safe handling method.
6. Gently Lift the Basket and Transfer the Cooked Food
Remove the food from the deep fryer by lifting the basket slowly. You can transfer it to a drying rack to pat off the excess oil with a paper towel.
At this stage, the insides of the food will be extremely hot. So allow it a few minutes to cool down before serving.
Here are a few things to remember while removing food from a deep fryer:
- Lift the basket gently once the food is cooked and let excess oil drain over the reservoir. Avoid vigorous shaking that can splash hot oil.
- Place the food on a drying rack or paper towels and let it cool down a bit before use.
- Wait until the oil and appliance are completely cool before draining or cleaning. Follow the manual for whether the lid should be fitted during cooling. Make sure it is out of the reach of children or pets, as hot oil is dangerous and can cause accidents.
7. Wait for The Oil to Cool to Discard or Store
After frying, turn off and unplug an electric fryer as its manual directs. Let the oil and appliance cool completely before moving, draining or cleaning them; cooling time varies with the amount of oil.
Only after the oil is fully cool should you filter and store it for reuse or put it in a sealed disposable container for disposal according to local rules. Do not pour it down a drain.
Interesting Further Reading: Can A Deep Fryer Explode? (What Causes Explosion + How To Avoid It)
The Importance Of Choosing The Right Type Of Oil
When choosing an oil for deep frying, the main aspect to consider is its smoking point.
The smoking point is the temperature at which the oil breaks down.
When the oil reaches this temperature, it becomes unstable.
If you further increase the heat, it will break down and release harmful toxins.
Since deep frying involves heating of oil to a very high temperature, choose an oil with a high smoking point.
It will allow you to safely heat the oil to the temperature mentioned in the recipe.
Use an oil that the fryer manual permits. Oils differ in heat tolerance and flavor, and some models prohibit solid fats, including coconut oil that is solid at room temperature.
So, you may also like to consider this factor if you do not want the flavors of the food to be affected.
Always use the right amount of oil.
For an electric fryer, use its minimum and maximum fill marks rather than a universal half-full rule.
Use the level indicator inside the deep fryer as a guide.
Additionally, pour the oil only when the deep fryer is turned off and cool.
