I used to think I was really cool and used olive oil for everything because it's "healthier." But you have to consider using different oils based on the dish you're making and how you plan to cook it. Depending on whether you plan to bake, fry, broil, or grill, a different oil will yield different results in your food, and give you more control over the cooking time and temperature. I usually keep extra virgin olive oil, vegetable oil and peanut oil in my pantry. Here are some things to think about when deciding which oil to use.
Smoke Point: The Number That Determines When Oil Goes from Tasty to Terrible
As you heat a fat of any kind, it begins to break down into free fatty acids and glycerol. As the temperature rises, the glycerol breaks down further and produces a bitter-smelling, acrid chemical called acrolein. It's that acrolein in the smoke that makes your eyes itch, and it's also what makes the food you cook in that overheated oil taste terrible.
If you plan to fry or grill, you want an oil that will stand up to high heat without breaking down on you. If you're going to use the oven, you have some more flexibility depending on whether you plan to bake, broil, and the temperature you set. With the right oil and the right cooking method, you'll taste a noticeable difference in your food.
Use Flaxseed Oil, Olive Oil, and Butter for Low-Temperature Cooking and Baking
As a rule, unrefined oils, dairy products, and animal fats have the lowest smoke points, and are best suited for lower-temperature cooking like baking, simmering, and low-heat pan frying.
Use Coconut Oil, Canola Oil, and Extra Virgin Olive Oil for Medium-Heat Cooking and Frying
Most of your middle of the road oils have applications in low-heat and cold preparations but can also be used on the stove or in the oven
Use Peanut Oil, Avocado Oil, and Ghee for High-Heat Grilling and Deep Frying
The highest-smoke point oils are generally reserved for high-heat frying, brushing on the grill, and deep frying
(Inspired by Lifehacker)