Although having lots of different oils in the kitchen might seem like a good idea, providing different flavors and variety, it actually may not be the way to go. Different oils have different structures, oxidation levels and smoke points (when they reach an unstable temperature).
When talking about just storing your oils, over time heat and light can impact oils’ taste and quality and they can go rancid (over months or years, depending on the oil), releasing very harmful properties to health.
So what oil is best, or what should you use? It's not an easy straightforward answer. There’s going to be significant variations based on how long you’ve had the oil, how it’s been stored, what brand it is, and so on. Make the best decision possible and take precautions when you can. It’s best to use just one or two types of oil. Personally, I use olive oil and avocado oil daily, and I also keep a very small jar (it's more expensive) of macadamia nut oil because I like it's flavor and nutritional structure, primarily adding it to shakes. Don’t buy a huge container of oil if you don’t use it frequently. Store them in a cool, dark place and replace any that any smell bitter or bad at all. Here is a more detailed breakdown of oils in order of their smoke points, lowest to highest...
Olive Oil - Not all olive oil is created equal. Buy extra virgin olive oil, great flavor use primarily as a non-cooking oil but can be used for medium heat cooking (160°C or 320°F)
The olive oil industry is huge. In fact, there is an International Olive Council (IOC). There are 4 different kinds. Here’s the two you should get: Extra virgin olive oil- Made with the highest quality olives without chemical solvents and basic processing procedures (no bleaching or deodorizing)Virgin olive oil- Made by slightly lower quality olives, but still without chemical solvents and only with basic processing.
The two to avoid: Refined olive oil- Goes through the bleaching and deodorizing processes, ruining the quality of the oil. The IOC has labeled these “Not fit for human consumption” – that should say a lot. Light olive oil or just “olive oil” is a blend of olive oils (virgin and refined).
Olive oil is primarily made from monounsaturated fats(73%), with a relatively small amount of saturated (14%) and polyunsaturated (13%) fats.
Is olive oil safe to cook with at any heat? While many say it’s not safe, studies say otherwise. Olive oil is loaded with antioxidants and polyphenols, which can prevent oxidation from occurring.
Studies show that a quality extra virgin olive oil is great for any cooking below it’s smoke point (191 degrees Celsius). Virgin olive oil is almost as good if you are trying to keep the cost down.
Coconut Oil - Great flavor, tons of uses and variety but do not consume if you have cholesterol issues. Slightly higher smoke point than olive oil (177°C or 350°F)
Coconut oil is mainly derived from the flesh of the drupe. You can easily find both cold-pressed unrefined coconut oil and refined coconut oil.
Coconut is unique in that it’s almost entirely made of saturated fats. These fats are mainly medium-chain triglycerides (MCTs), which can be very beneficial and a great energy source. While you don’t want to consume a huge amount at a time, consuming coconut oil in small doses can be healthy.
What about stability? Coconut oil is by far the most resistant oil to oxidation that we looked at. Combine that with the fact that it usually comes in a tight glass jar, as long as you keep it away from light, it should last a long time (1-2 years) before you need to be concerned about rancidity.
As with any oil, I always recommend using it for cooking below it's smoke point.
Sesame Oil - Similar calorie content as olive oil, more equal parts poly and monounsaturated fats. Smoke point at 210°C - 410°F.
Sesame seed oil shares a lot of the same problems as vegetable oils. It contains a high amount of polyunsaturated fats (43%) and minimal antioxidants. It should not be heated much, as it will readily oxidize and form free radicals.
Most of the sesame oil sold in stores is refined, which means it’s already past saving.
Bottom line: sesame seed oil isn’t particularly nutritious and is an unstable oil that should not be used for cooking. Use it primarily for flavor.
Macadamia Nut Oil - This one you may not have heard much about. Just like olive oil, macadamia nuts can literally be squished to extract oil, which is great in comparison to corn and other oils that need chemical solvents. Macadamia nut oil has a smoke point of at least 210°C, or 410°F – remarkable.
Now the problem with most nut oils is that they are filled with polyunsaturated fats, which makes them unstable under heat. Macadamia is the exception. It is made of about 12% saturated fats, 84% monounsaturated fats, and just 4% polyunsaturated fats. On top of that, it is loaded with vitamins, minerals, and phytochemicals.
Combining that oxidative resistance with its high smoke point, macadamia nut oil is great for just about any type of cooking. The one downside is that it’s more expensive than most oils, but the quality is worth it.
Grape Seed Oil - Be careful using too much of this. It’s high in omega-6 fatty acids, which doesn't sound bad, right? Too much in your diet can have adverse health effects, especially when compared to your omega-3 count. Smoke point at 216°C or 420°F
Grape seed oil is made from, shockingly, the seeds of grapes. It’s one in a long chain of the latest “superfoods” promoted, but as with the rest of them, be cautious.
The most important thing you need to know about grape seed oil is that it is about 70% polyunsaturated fat (almost all omega-6). This renders it terrible as a cooking oil. It has a good amount of vitamin E, but that’s about it.
While virgin grape seed oil isn’t the worst for uncooked foods, it’s far from the best and not worth its high price. I steer clear of it.Avocado Oil - Use for high heat cooking as it has the highest heat tolerance, or smoke point of 271°C or 520°F. Avocado oil shares a similar fat profile as olive oil. It is mostly monounsaturated, but has a bit less polyunsaturated fats in favor of saturated fat, which makes it a little better for cooking.
While the high amount of polyunsaturated fats might lead you to suspect that avocado oil will also be prone to oxidation in heat, avocado oil performs similar to olive oil under heat. The high amount of vitamin E is highly effective in preventing anti-oxidation.
Avocado is a good oil to cook with at any temperature under its smoke point. Unrefined avocado oil has a fairly high smoke point of 195 degrees Celsius.
The "Consume Sparingly" List:
Overall butter is pretty terrible to cook with due to it's easy oxidation and breakdown. It's not actually an "oil" but we use it in the same category. It has a very little amount of protein and carbohydrates that contributes to it's low smoke point.
If you do opt to use butter to cook, do so at a low heat. Also, store it in an airtight container in the fridge to avoid oxidation.
Popular of course with Paleo crowds. The smoke point of lard will vary depending on the cut it came from, although most pork lard has a smoke point of about 190°C.
It’s typically about 45% monounsaturated fats, 40% saturated, and 10% polyunsaturated. In short, it’s fairly resistant to oxidation. Tallow is fat that comes from beef, which has a similar profile, but actually less polyunsaturated fat, which is a good thing.
In general, animal fats are a good choice for any cooking below their smoke point. While they don’t have any significant antioxidants, the fat profile ensures they remain relatively stable. You can buy lard or tallow from most stores or make your own inexpensive rendered animal fat.
The "Do Not Consume" List:
Here’s an interesting one. Canola oil comes from the rapeseed plant, and with a name like that, you should probably have low expectations. Originally, the oil from a rapeseed plant isn’t even edible, which should raise red flags already. A compound called erucic acid (gout) has to be removed first.
Don't listen to the Omega-3 claims. Don't buy or eat canola oil.
Probably the most popular oils are also unfortunately the worst. Corn oil is sometimes just called vegetable oil.
Both corn and peanut oils are almost always sold as refined oils. How else would you get fat out of corn without chemical solvents?
They both have a high amount of polyunsaturated fats (32% in peanut, 59% in corn). Similar to canola oil, these fats are heavily damaged and will lead to free radical formation during the bleaching and deodorizing processes.
Do not eat corn oil, vegetable oil, or peanut oil.
Palm Oil has an attractive fat distribution, composed of 50% saturated fat, 39% monounsaturated fat, and 11% polyunsaturated. Additionally, it has a high amount of vitamin E (an antioxidant) that prevents free radical formation during cooking. Overall, this makes it good for cooking at any temperature below its smoke point, which is low, at only 150°C for unrefined palm oil.
The big problem with palm oil is that in places like Indonesia, palm oil plantations are responsible for wiping out a huge percentage of the orangutan population and deforestation. If you look at packaged foods, its everywhere. While palm oil can be good for low-heat cooking, me personally it's not worth it. There is a slew of other oils out there you can use.