Deep Fryer Oil Storage: Safe Practice?

Deep fryers are a handy kitchen tool for frying food, but they require a lot of oil. So, can you keep the oil in a deep fryer and reuse it? The answer is yes, but only for a certain period and under specific conditions.

Firstly, it's important to note that oil generally has a shelf life of up to two years if stored properly. Once opened, oil should be used within three months. For deep fryers, oil can be kept and reused for about a month, but this depends on several factors.

The type of food being fried makes a difference. For example, frying fish or seafood can make the oil difficult to reuse even after one use due to the pungent smell. Additionally, the quality of the oil matters; high-quality oil can be reused more often than regular oil.

To prolong the life of the oil, it is recommended to filter it after each use to remove food particles, store it in a cool, dark, and airtight place, and not to overuse it. Oil should not be reused more than four to five times, as it will lose its quality and nutritional value, and develop a burnt smell.

It is also crucial to know when to change the oil. If the oil has turned dark, foams when hot, or has a bad smell, it should be discarded immediately.

How long can oil be kept in a deep fryer?

The longevity of oil kept in a deep fryer depends on several factors, including the type of oil, the frequency of use, and the types of food being fried.

Frequency of Use

If you're a frequent fryer, you may need to change the oil in your deep fryer every week or two. This is especially true for high-volume fast-food restaurants, where fryers are constantly in use. On the other hand, if you only use your deep fryer occasionally, you may be able to stretch the oil for a month or so.

Type of Oil

Not all oils are created equal when it comes to deep frying. Oils with a high smoke point, such as canola oil, sunflower oil, peanut oil, and avocado oil, are more stable at high temperatures and will last longer.

Type of Food

The type of food you're frying also makes a difference. Frying breaded foods, especially fish and seafood, can shorten the lifespan of your oil due to the pungent smell that lingers. Raw foods will also have a similar effect.

Storage

Proper storage is key to extending the life of your oil. Always allow the oil to cool before storing it in a sealed, light-proof container. Refrigeration is recommended to maximize longevity. Keeping the oil in a cool, dark, and airtight place will also slow down oxidation and preserve the flavour.

Signs of Spoilage

Even with proper storage, oil can go bad. Keep an eye out for changes in colour (darkening), smell (rancid, soapy, or chemical odour), and texture (foaming when hot). These are signs that it's time to change your oil.

In summary, the lifespan of oil in a deep fryer can vary from a few days to a few months, depending on usage, oil type, food type, and storage conditions. Proper storage and maintenance can help extend the life of your oil, but it's important to keep an eye out for signs of spoilage to ensure food quality and safety.

How to store used frying oil?

Storing used frying oil is a great way to reduce waste and cut costs. However, it's important to do it right to avoid ruining the oil and to prevent harmful free radicals from developing. Here are some tips on how to store used frying oil:

Cool the Oil Completely:

After frying, turn off the heat and let the oil cool down to room temperature. This is an important safety precaution, as oil burns can be dangerous.

Strain the Oil:

Once the oil has cooled, strain it through a fine-mesh sieve or cheesecloth to remove any food particles or debris. These particles can burn and make the oil taste nasty when reheated.

Transfer to a Clean, Sealed Container:

Pour the strained oil into a clean, sealed container, such as a glass jar or the original oil bottle. A funnel can be useful for this step.

Store in a Cool, Dry, Dark Place:

Store the sealed container in a cool, dry, and dark place, such as a cupboard away from the oven or other heat sources. Moisture, heat, and light can cause the oil to oxidize and ruin its flavour.

Label the Container:

It's helpful to label the container with the date, the type of food the oil was used for, and the number of times it has been used. This will help you keep track of the oil's freshness and prevent mixing different types of oil.

Reuse Within a Few Months:

Used frying oil can typically be reused anywhere from two to eight times, depending on various factors. However, it's best to use it within a few months. Oil can go rancid over time, so it's important to monitor it for any signs of spoilage.

Dispose of Oil Properly:

When the oil has reached the end of its lifespan, dispose of it properly. Do not pour it down the sink drain, as it can clog your pipes. Instead, transfer it to a closed container and throw it away, or recycle it at a designated location.

How to know when oil needs changing

There are several signs that indicate it's time to change the oil in your deep fryer. Here are some key indicators:

• Dark Colour: Oil that has gone bad will turn darker than usual. This is a sign of oxidation due to age, heat, or light exposure.
• Unpleasant Smell: Rancid oil may have a soapy, chemical, or burnt odour.
• Foaming: If the oil foams or bubbles when heated, it has likely degraded and needs to be replaced.
• Taste: Oil can impart a burnt or stale taste to the food, indicating that it needs to be changed.
• Smoke: If the oil starts to smoke excessively, it may be a sign that it has degraded and needs to be replaced.
• Slow Cooking: If it takes longer than usual for your food to cook, it could be a sign that the oil is losing its effectiveness.
• Usage Frequency: Depending on usage, oil in a deep fryer can last for about a month. However, if you've used the oil 3-4 times, its quality and nutrition deteriorate, and it's recommended to replace it.
• Type of Food: The type of food being fried also impacts the oil's lifespan. For example, frying breaded foods, meat, or poultry may require changing the oil after 2-4 uses, while non-breaded foods like vegetables can be fried 6-8 times before changing the oil.
• Filtration: Regularly filtering the oil can extend its lifespan. However, if you don't filter the oil after each use to remove food particles, you may need to change it more frequently.
• Storage: Proper storage is crucial. Store oil in a cool, dark, and airtight container to prevent oxidation and maintain its quality.

It's important to note that these guidelines may vary depending on the type of oil and other factors. Always refer to the specific instructions for the oil you are using and exercise your best judgment to ensure food safety and maintain the quality of your fried foods.

Ways to keep oil in good condition

Oil is an essential element of a kitchen and can be stored and reused in a deep fryer. Here are some ways to keep oil in good condition:

• Filter the oil: After frying, filter the oil using a skimmer to remove any large pieces of food. Then, strain the oil using a fine-mesh strainer or cheesecloth to remove smaller particles.
• Store the oil properly: Keep the oil sealed in the deep fryer with an appropriate cover. Store it in a cool, dry, and dark place, away from humidity, light, and heat.
• Use the right type of oil: Choose an oil with a high smoke point, such as peanut oil, canola oil, or safflower oil. Oils with high levels of monounsaturated fats, like canola or peanut oil, are more heat stable.
• Avoid overheating: Overheating the oil will cause it to break down quickly. Use a thermometer to monitor the temperature and avoid frying above the smoke point of the oil.
• Avoid frying without a coating: Frying without a coating will cause the food to absorb more oil and lower the oil's quality.
• Avoid food seasonings: Seasonings like salt and chili powder can make the oil darker and thicker, affecting its quality.
• Regularly clean the deep fryer: Keep the deep fryer clean to prevent food particles and debris from building up and contaminating the oil.
• Limit the type of food fried: Raw foods, fish, and seafood can make it difficult to reuse the oil due to the pungent smell they leave behind.
• Use an electric fryer: Electric fryers have a cooler area at the bottom where food particles can fall without burning, helping to extend the lifespan of the oil.

Best oils for deep frying

Deep-fried foods are a staple of the fast-food industry and play a role in many traditional cuisines. However, they can be unhealthy if not cooked in the right oils. The best oils for deep frying have a high smoke point, are stable at high heat, and have a neutral flavour.

Coconut Oil

Coconut oil is a healthy choice for deep frying because it is highly resistant to heat. Over 90% of the fatty acids in coconut oil are saturated, making it less susceptible to heat damage. Coconut oil has been shown to remain stable even after 8 hours of continuous deep frying at 365°F (180°C). However, some people may not enjoy the flavour or smell of coconut oil, so it is best to try a few brands to find one that suits your taste.

Animal Fats

Animal fats such as lard, tallow, ghee, and fat drippings are excellent choices for deep frying. They add flavour and crispness to food and are highly resistant to damage when fried. Most fatty acids in animal fats are saturated and monounsaturated, making them ideal for high-heat cooking. It is best to choose animal fats from pasture-raised or grass-fed animals, as these have higher amounts of saturated and monounsaturated fats.

Olive Oil

Olive oil is one of the healthiest oils for deep frying. It is highly resistant to heat due to its high monounsaturated fatty acid content. In one study, researchers used olive oil in a deep fryer for over 24 hours before it oxidised excessively. However, the flavour and fragrance of olive oil may deteriorate when heated for long periods.

Avocado Oil

Avocado oil has a similar composition to olive oil, with mainly monounsaturated fatty acids and some saturated and polyunsaturated fats. Refined avocado oil has a high smoke point of 520°F (270°C) and a slightly nutty taste.

Peanut Oil

Peanut oil, also known as groundnut oil, has a high smoke point of about 446°F (230°C) and a neutral taste, making it a popular choice for deep frying. However, it contains a relatively high amount of polyunsaturated fats (around 32%), which makes it more vulnerable to oxidative damage at high temperatures.

Palm Oil

Palm oil consists mostly of saturated and monounsaturated fats, making it a great choice for deep frying. The unrefined variety, known as red palm oil, has a neutral flavour. However, some people have concerns about the sustainability of cultivating and harvesting palm oil.

Canola Oil

Canola oil is commonly used in restaurants for deep frying due to its low price in bulk, polyunsaturated fat content, and high smoke point of 400°F (204°C). However, it is high in polyunsaturated fatty acids, which can lead to the formation of large amounts of oxidized fatty acids and harmful compounds when used for deep frying.

Vegetable Oil

Vegetable oil is a blend of different plant-derived oils such as corn oil, soybean oil, and sunflower oil. It has a high smoke point between 400°F and 450°F (204°C and 232°C), making it suitable for deep frying, which is typically done at temperatures around 350°F (176°C). Vegetable oil also has a neutral flavour, allowing the taste of the food to shine through. It is cost-effective and can be reused multiple times, making it a popular choice for home cooks.

Frequently asked questions