Cooking Oil Guide

Cooking oil is a staple when it comes to making a great meal, but all the options available at the supermarket can make the choice of what to use very overwhelming. Different cooking oils serve a different purpose, so I’ve put together a cooking oil guide to help you pick the right one for you.

You’ll notice some different types of oils on the shelf of your local supermarket that have extra words like unrefined, refined, virgin, extra virgin or organic. These terms refer to how the raw product that oil comes from – olives, nuts, seeds – is extracted.

An oil that is extra virgin or unrefined is one that has undergone minimal extraction or processing from its original form to create the oil, usually done through pressing, involves minimal heat and sometimes extracted using chemicals. Unrefined oils tend to have a stronger flavour and retain more of their nutrients, but aren’t suitable for deep-frying. These types of oils will usually say the words virgin, extra virgin or unrefined to describe how it’s been processed, so know which one to pick.

In contrast, refined oils are still pressed but undergo further treatments which can include using filters, extreme temperatures and sometimes chemicals that remove particles and impurities. While refined oils have fewer nutrients compared to their unrefined counterparts, the refinement process produces oils that have a longer shelf life, a neutral flavour and are suitable for deep-frying. These types of oils include canola oil, sunflower oil, vegetable oil, peanut oil, avocado oil and mild/light olive oil which has a mixture of refined and unrefined oils.

You’ll also find organic oils, but they can be refined or unrefined, it just describes how the farmer cultivates, grows and treats their crops. In my kitchen, I use 3 different types of cooking oil, all for different types of things; olive oil, extra virgin olive oil and a seed oil; each serving a different purpose.

Seed Oils

Seed oils are a really great all-purpose oil, great for regular cooking, deep-frying, making sauce and baking because they are cost-effective and have a neutral flavour. I use it to season my cast iron and carbon steel pans, to deep-fry and making sauces like mayonnaise because I like the neutral taste, and they are very cost-effective. Canola oil is one of the better choices of seed oils, it has similar properties to extra virgin olive oil in terms of the nutrients it provides. It contains vitamin E, has omega 3 and omega 6, higher in monounsaturated fat and is lower in saturated fat when compared to vegetable oil. Vegetable oils are a little ambiguous as they can be a mix of different types of seed oils, meaning the nutrients change and higher saturated fat content.

There is a lot of misinformation and fearmongering online that says you shouldn’t be cooking with seed oils; they’re bad for you and so on. It’s all nonsense; lies sell, and the truth is boring. There has been SO MUCH research into seeds oils and its impact on our overall health. When included in your diet through home cooking and preparation, seed oils are actually very beneficial, as they’re lower in saturated fat and contains essential nutrients that support cardiovascular and metabolic health.

The association between seed oils and “bad health” may be because of their use to make discretionary and ultraprocessed foods like those from fast-food restaurants. Often fast food restaurants reuse their oil, often without cleaning/straining the oil between cooking batches of food which can impact the quality of the oil, read below: Can cooking oil be reused?, to find out more about how this impacts our health. This is by no means me demonising fast food or ultraprocessed food, we all eat it, we all enjoy it; however, everything should be in moderation.

There is also misinformation surrounding the omega 3s and 6s found in seed oils. Our bodies can’t produce them so we need them from our food sources, which seed oils have plenty of. Critics of seed oils argue that the omega-6 fatty acids they contain contribute to chronic inflammation. Their claim is based on the idea that linoleic acid, the main omega-6 fat in these oils, is converted in the body into arachidonic acid, which serves as a precursor for compounds involved in inflammatory processes. What many critics of seed oils fail to acknowledge is that arachidonic acid is also a building block for compounds that help resolve inflammation, not just trigger it. Research increasingly shows that omega-6 fatty acids are not inherently harmful.

Mild or Light Olive Oil

I use it for cooking pretty much everything else. You can use it to deep-fry, but it isn’t as cost-effective as using seed oils. Mild Olive Oil is my preferred oil as an all-rounder for cooking as it has a subtle olive taste that doesn’t overpower dishes and has a higher smoke point compared to extra virgin olive oil.

I like to use mild olive oil for baking as well, as the taste is subtle enough in baked goods – such as banana bread – that you won’t notice the taste and is a great alternative to using butter or shortening as a fat, as mild olive oil has less saturated fat and packs more nutrients. In saying that, I don’t think oil is suitable for every baked good; I think cookies are better made with butter as the fat source.

Extra Virgin Olive Oil

This oil is best used for cold preparation such as dressing, sauces and over salad. Extra virgin Olive Oil is an unrefined oil and because of that, it doesn’t have a higher smoke point compared to other oils. Because it’s unrefined, it has a stronger olive taste and is more nutrient dense than a mild olive oil because it has only been minimally processed before bottling and is why many people prefer to use it compared to a mild olive oil. Most general sautéing should be okay if you don’t reach its smoke point.

You can absolutely use extra virgin olive oil for general cooking as its smoke point is between 160-210 degrees Celsius, but I do suggest you leave it for some of the lower temperature cooking you would do such as eggs or lower heat sautéing. Some people just don’t like the taste of extra virgin olive oil as well because of the strong olive taste, so I recommend a mild olive oil.

I suggest you do your research and pick the one that is best for you and your lifestyle. Aussie supermarkets regularly have vegetable oil and olive oil on sale. I wouldn’t buy the biggest bottles they have just because they’re cheaper unless you’ll use the oil regularly. Look for something in a size suitable for your at home oil usage.

High Heat Cooking/Deep Frying

Many of the medium/high heat oils such as canola, vegetable, rice bran, safflower, and sunflower are the best bets for deep-frying and that’s because they’re neutral cooking oils. Neutral oils have little to no flavour which allows you to taste the other ingredients in your dish so that they don’t compete, such as making garlic or chilli oils, dressings and baking.

Ideal deep-frying temperature is between 160 – 180 degrees Celsius. Seed oils like the ones listed above are ideal because a lot of it is used at once, is cost-effective to replenish and less likely to burn at higher heat. You absolutely can deep-fry with olive oil or extra virgin olive oil, but I don’t recommend it because of how costly it is to replenish and the likeliness of olive oil imparting flavour into your food you may not enjoy.

High heat cooking usually involves stir fries and searing meat like steak, where temperatures usually reach well beyond 210 degrees Celsius. This is where high smoke point cooking oils come in handy which include avocado, sunflower, safflower and peanuts oils. You can deep-fry with any of these types of oils, but many are costly to replenish, and it’s why I only recommend it for searing or stir fries, as you won’t be using as much oil.

There may be some instances where you would want to use an olive oil for shallow frying such as schnitzels or Greek/Italian meatballs as I believe the flavour of the olive oil can compliment the taste of those types of foods and I absolutely think olive oil is a great option for shallow frying as you won’t be using as much as deep drying. Make sure you have a food thermometer handy to ensure that the internal temperature of your food is at a safe level, especially important for poultry.

What is smoke point?

The smoke point of oil or fats represents its resistance to heat, the temperature it reaches before it stops shimmering and starts to smoke and break down. Smoke points of fats and oils can vary between 170 – 270 degrees Celsius and that depends on its refinement – more refinement: high smoke point; lower refinement: lower smoke point. Oils that are more refined have a higher smoke point and that’s because refining removes particles that can cause oil to smoke and why they are used for deep-frying. Unrefined oils have more particles in them that will produce smoke and burn when cooked at high temperatures.

Why is smoke point important?

Going beyond an oils smoke point will burn the oil, making it break down, causing it to burn and impart burnt and bitter flavours into your food. Smoking fats destroys many phytochemicals and nutrients in the fats and your food, while also releasing a chemical called acrolein, which is what makes your food taste bitter and burnt. It also releases free radicals, chemicals that can contribute to the formation of harmful compounds in food and may negatively impact health by promoting oxidative stress in the body, which is linked to inflammation, aging, and chronic diseases.

While smoking fats isn’t a bad thing in some circumstances such as stir-fries and searing steaks, where you need to have a high heat, you just need to have a high heat oil to go along with it. Even when using high smoke point oils, you should still be weary about the temperature you’re cooking at. It’s also important to consider that over time, an oils smoke point doesn’t remain the same, it will degrade the longer it is exposed to heat, especially if the oil is used multiple times. Batter and breading from foods that fall off into oil can also degrade oil and lower its smoke point too.

Storing Cooking Oil

Store cooking oil in a cool, dark, and dry place—such as a pantry—away from heat, sunlight, and kitchen appliances to prevent it from going rancid. Always keep oils tightly sealed in containers to protect them from light and air. If you have a large supply of cooking oil and want to decant into smaller bottles, grab some Kilner or Oxo bottles and some funnels (this will make it easier to pour from one bottle to another), and store them in a cabinet or dark space nearby your cooking area. Large bottles can be stored in your pantry. If you plan to do deep-frying, don’t forget to keep those empty oil bottles so that they can be filled up with any cooking oil that you’re finished with and dispose of it correctly.

Can deep-frying cooking oil be reused?

Cooking oil can be reused, however, food particles need to be strained be stored properly to prevent flavour transfer and spoilage; it’s best to reuse it only a few times (around 3-4), avoid reusing oil from fish or strong-flavoured items for delicate foods, and dispose it if it becomes dark, foamy, or smells rancid.

When I want to reuse cooking oil, I place a sieve/mesh strainer over a bowl, with a paper towels or a cheese cloth in the sieve, pour the cooled down oil over the paper towels/cheese cloth and let it pass through into the bowl, this can take a while if you’re using a small bowl/sieve and needing to deal with lots of oil. I then pour that oil into a clean bottle until I’m ready to use it again.

I know it seems tedious and annoying to do it this way, however, unless you have a really fine mesh strainer, it’ll be difficult to remove all the impurities. If you don’t remove all the impurities, using the oil with anything leftover can degrade the quality of the oil because those impurities can burn. It’s also why it should only be used 3 to 4 times, as heating oil up over and over again can also degrade it. Oxidation and heat can break down the oil and lower the smoke point.

Disposal of Cooking Oil

You should never dispose of your cooking oil down your drains or sinks. It can cause issues with your plumbing and on the environment. Small amounts of oil can go into your rubbish bin with a container or poured into your garden, otherwise for large amount, place it into a large container (save those large oil containers) and take it to a cooking oil recycler that will take residential amounts of cooking oil or check with your local council to see if they have a disposal facility. Most local councils will have some sort of guide on cooking oil disposal.

Cooking Oil Chart

I have also added a Cooking Oil Smoke Chart below to help make your choice of oil easier. Many of the low heat cooking oils or fats can be used for deep-frying, but caution is suggested so that they don’t burn. I’ve added some additional types of fats common in Australia such as Duck fat, Copha and Supafry. Duck fat is great for making roasted duck fat potatoes. I like using Copha for baking products like biscuits and other sweets and is suitable for melting over a double boiler as it is indirect heat and will melt at a low heat.

There are many oils available at Aussie supermarkets that I haven’t added to the list below, purely because I don’t think they belong there and aren’t a suitable cooking oil as the base for cooking a dish. Oils like sesame, walnut and macadamia are suitable as finishing oils rather than cooking oils. In saying that, sesame oil is great when adding it to a marinade for Asian dishes.