Deep Fryer Oil Change: When And Why?

Deep fryers are a great way to make delicious fried foods, but what do you do with the oil when you're done? Can it be left in the fryer, or does it need to be removed and stored?

The answer is that it's generally not recommended to leave oil in the deep fryer after use. While it may be tempting to just leave it there, especially if you plan on frying again soon, oil can turn rancid and become toxic if not cleaned and stored properly. It's important to remove the oil from the fryer after each use, strain it to remove any food particles, and store it in a cool, dry place until the next time you need it. This will help extend the life of your oil and ensure that your food tastes its best.

There are a few things to keep in mind when reusing frying oil. First, oil takes on the flavour of whatever you fry in it, so it's best to fry similar items in previously used oil. Second, the order of operations matters – vegetables tend to have the lowest impact on oil, while breaded items can leave lots of small particles behind that can burn and infuse the oil with a bitter flavour. Finally, be sure to pay attention to your oil and look for any signs of degradation, such as a dark colour, smoky odour, or foaming at the top. If you notice any of these, it's time to dispose of the oil safely and start fresh.

Oil storage

Oil can be left in a deep fryer, but it is not recommended. Oil should be removed from the deep fryer after each use, strained, and stored correctly. This is because oil can degrade over time, and the quality of the oil will determine the quality of the food fried in it.

To store oil correctly, it is important to keep it in a cool, dry, dark place, preferably in a sealed or airtight container. This is because oil degradation is caused by a number of factors, including exposure to air, water, and high temperatures.

Firstly, any contact with air causes oxidation in oil. This process is accelerated by high temperatures, metal alloys, surface exposure, and even UV light. Therefore, it is important to store oil in an airtight container, away from heat sources, and in a dark place.

Secondly, when water interacts with oil, it can cause it to taste tainted or acidic, especially when exposed to high temperatures and heating/cooling cycles. Therefore, it is important to ensure that oil is thoroughly dried before storing and to store it in a dry place.

Finally, degradation can also occur when oil is exposed to high temperatures. This can cause the oil to form volatile and non-volatile compounds, which can lead to foaming and increase the possibility of hydrolysis. Therefore, it is important to allow oil to cool completely before storing and to store it in a cool place.

Additionally, oil should be strained before storing to remove any food particles, as these can cause the oil to taste bitter or rancid over time. It is also recommended to label the container with the date of first use and the number of successive uses, as oil should be changed after eight to ten uses or if it starts to show signs of degradation.

Overall, by following these storage guidelines, you can help ensure that your oil remains in optimal condition for future use and reduce the waste and cost associated with frequent oil changes.

Oil reuse

Oil can be reused for frying several times, but it's important to follow certain steps to ensure safety and maintain the quality of the oil. Here are some guidelines for reusing frying oil:

Storing the Oil in the Deep Fryer

Leaving oil in the deep fryer between uses is generally safe, especially if your fryer has a cold zone, which helps prevent particulate buildup. However, it's important to cover the fryer to avoid contact with air, which can cause oxidation and oil degradation. If you plan to use the oil within a few days, you can leave it in the fryer, but make sure to cover it securely.

Straining and Storing the Oil

Before storing the oil, it's crucial to strain it to remove any food particles, crumbs, or sediment. You can use a cheesecloth, coffee filters, or a fine-mesh strainer for this purpose. Once the oil has cooled completely, pour it through the strainer into a clean, resealable container, such as a glass jar or the original oil container. Label the container with the date, the type of food fried, and the number of uses. Store the oil in a cool, dark place, such as a cupboard or pantry, until you're ready to use it again.

Frying oil can typically be reused anywhere from two to eight times, depending on various factors. The type of oil, the food being fried, and the quality of straining all play a role in how many times you can reuse it. Additionally, pay attention to any changes in the oil, such as discolouration, foaming, or a rancid smell. These are signs that the oil needs to be discarded. As a general rule, it's recommended to discard frying oil after three to five uses or if it has been stored for more than one to two months.

Safe Disposal of Used Oil

When it's time to dispose of the oil, never pour it down the sink drain, as it can cause plumbing issues. Instead, solidify it using a product like FryAway, then throw it away in a sealed container. Alternatively, you can recycle used oil by finding a local disposal centre or recycling drop-off that accepts used cooking oil.

Oil disposal

There are several ways to dispose of used frying oil, but one thing is clear: you should never pour oil down the drain or toilet. Oil can congeal and clump, clogging your pipes and leading to a plumbing disaster. It can also cause fatbergs—enormous masses of fat, oil, and grease that clog pipes and contaminate local waterways.

• Solidify it, then trash it: Use a product like FryAway to solidify the oil into a block that can be thrown away.
• Transfer it to a closed container, then toss it: Pour the oil into a sealable disposable container (like the bottle it came in) and throw it away.
• Recycle it: Check if there are any recycling drop-offs near you that accept used cooking oil. Some cities recycle used oil into biodiesel, which is used as fuel for motor vehicles and heating oil.
• The container method: Pour cooled oil into a disposable container (e.g., old sour cream or cottage cheese containers) and seal it shut before throwing it away.
• The freezer method: Pour leftover oil into an old can and place it in the freezer until hardened. Then, scoop the solidified oil into the trash.
• The plastic bag method: Pour cooled oil into a plastic trash bag that already has some debris like old paper towels or veggie peels to help absorb the grease.
• Combine with other material: Mix the oil with an absorbent material like cat litter, sand, or sawdust. Save the mixture in a used container until it's time to empty the litter box, then dump the oil-soaked litter into the trash.

Additionally, some local waste departments may have specific guidelines or protocols for disposing of cooking grease, so be sure to check before tossing your used oil.

Oil filtration

Step-by-Step Guide to Oil Filtration:

• Turn off the fryer and allow the oil to cool: Before beginning the filtration process, make sure the fryer is turned off and unplugged. Allow the oil to cool down slightly, but it should still be warm.
• Use a fryer filter machine: Invest in a good-quality commercial fryer filter machine. These machines are designed to pump the oil through a filtration system, removing food particles and other impurities. The Micro Filter King, for example, has a double filtration system that catches particles as small as 10 microns.
• Filter the oil regularly: It is recommended to filter your frying oil at least once a day, or more frequently if you use your deep fryer multiple times a day. Regular filtration will help extend the life of your oil and maintain its quality.
• Follow the manufacturer's instructions: When it comes to cleaning and maintaining your fryer filter machine, always refer to the manufacturer's instructions. This usually involves disassembling the machine, cleaning or replacing the filter, and washing the components with hot, soapy water.
• Store the filtered oil properly: After filtering the oil, store it in a cool, dark place until the next use. Use a sealed, light-proof container, such as a clean glass jar or a well-washed and dried plastic bottle. Label the container with the date of the oil's first use and add the date of each successive use.
• Dispose of oil properly: When your frying oil has reached the end of its lifespan, dispose of it properly. Do not pour it down the sink drain, as it can cause clogging. Instead, solidify it using a product like FryAway, then throw it in the trash. Alternatively, pour it into a sealable disposable container and toss it in the garbage.

Additional Tips for Oil Filtration:

• Use the right type of oil: Different types of oil have varying lifespans and suitability for deep frying. Oils with higher smoke points, such as peanut oil or canola oil, are better for deep frying and can be reused more times than those with lower smoke points.
• Strain the oil after each use: In between filtrations, it is important to strain the oil after each use. Use a fine-mesh strainer or cheesecloth to remove any large food particles or debris.
• Pay attention to the oil's condition: Oil that has become dark or dirty, smokes before reaching frying temperature, foams at the top, or has developed a rancid or unusual odour should be discarded, even if it hasn't reached its maximum number of uses.
• Use separate oil for different foods: Frying oil tends to take on the flavour of whatever is cooked in it. Therefore, it is recommended to use separate batches of oil for strongly flavoured foods like fish or spices.

By following these instructions and tips, you can effectively filter and maintain your deep fryer oil, ensuring that your fried foods are of the highest quality.

Oil degradation

Type of Oil

Different types of oil have varying levels of stability and resistance to degradation. Oils with a higher smoke point, such as peanut oil, avocado oil, and canola oil, are more suitable for high-heat frying and tend to have a longer lifespan. On the other hand, oils with a lower smoke point, like olive oil and coconut oil, are better for low-heat cooking and may not be as stable.

Temperature

The temperature at which the oil is heated also plays a significant role in its degradation. If the oil is heated too high, it can break down and become rancid more quickly. The optimal temperature range for deep frying is generally agreed to be between 325°F and 375°F (165°C and 190°C). Heating oil above 200°C can cause non-volatile compounds to form, leading to foaming and an increased possibility of hydrolysis.

Frequency of Use

The frequency of use also affects oil degradation. In commercial settings, deep fryers are often used continuously throughout the day, causing the oil to break down more quickly. Commercial deep fryer oil is typically changed every 1-3 weeks. In home settings, deep fryer oil can be left for longer periods, usually up to 3-6 months, depending on usage and maintenance.

Filtration and Maintenance

Regular filtration and maintenance are crucial in extending the lifespan of deep fryer oil. This includes removing impurities and debris through regular cleaning and filtering, as well as monitoring oil levels to ensure they remain at the recommended level.

Signs of Degradation

There are several signs that indicate when the oil needs to be changed due to degradation. These include off-flavours or odors, darkening of the oil, and the oil reaching its smoke point. It is important to regularly check the oil for these signs of degradation and change it as needed to maintain food quality and safety.

Frequently asked questions