Oil have a property known as smoke point. The smoke point of oil is the temperature at which the oil begin to break down and produce smoke. At these temperature, the oil breaks down into chemical like acrolein that can produce irritation in the eye and the lungs.
Additionally, oils that reaches their smoke point can taste bitter. It is therefore important to understand the smoke point of an oil that you are considering use in your kitchen to ensure that your food dont taste bitter and the oil wont smoke in your kitchen. Refined oils has higher smoke points than unrefined oils.
How to Choose and Store Cooking Oils
Removing the impurities and free fatty acid from oils during the refining process will allow the oil to have a higher smoke point, since these component tend to contribute to the degradation of oils. For these reason, oils like refined avocado oil have very high smoke point, and they is often used in tasks that involve high heat. Other oils with high smoke point include ghee (clarified butter), refined olive oil, sunflower oil, and peanut oil.
The chemical structure of the oil, particulary the type of fat that are contained within the oil, will impact how the oil react to heat. Oils that contain more saturated fats will remain chemically stable at high heat temperatures, such as oils like coconut oil and butter that contain high amounts of saturated fat. Unrefined oils will have lower smoke points due to the natural impurities contain within those oils.
While people often choose unrefined oils for its flavor, they will have a lower smoke point then refined oils. For instance, extra virgin olive oil will have a lower smoke point than refined olive oil; thus, chefs typically use extra virgin olive oil in salad dressing rather than in frying. Different type of oils are associated with different cooking method.
For deep frying recipes that require the oil to reach temperatures of between 350 and 375 degrees, oils like peanut oil and sunflower oil is best used. For high heat cooking methods of 400 degrees or above, people use oils like avocado oil or ghee, since they can withstand these high temperature. Butter should of been avoided for these type of cooking methods, as butter will begin to burn at these temperatures.
For stir-frying in a wok, you can use oils like sesame oil or canola oil. For baking recipes, oils like coconut oil or butter can be used due to their stability at moderate oven temperature. Another consideration for cooking oil is the flash point and fire point of the oil.
The flash point of oil is the temperature at which the oil will ignite if there is a flame present nearby. The fire point is the temperature at which the oil will sustain a fire once ignited. Both of these point should be avoided in the cooking process.
Furthermore, if there is a fire in the pan, covering the pan with a lid will extinguish the fire. You should not use water to extinguish a fire in a pan of cooking oil. Cooking oils contain different amount of nutrients.
For instance, flaxseed oil contain a high amount of omega-3 fatty acids. Flaxseed oil, however, should not be used in the cooking process due to the instability of flaxseed oil when heated. Walnut oil also contain omega-3 fatty acids, but it will become rancid quick if heated.
Canola oil has a balanced ratio of fats. Lastly, coconut oil and butter contain low amounts of omega-3 fats, but contain medium chain triglycerides that provide energy to the body. Cooking oil should be stored in a specific manner to ensure that the oil does not degrade.
Too much heat, light, or air can degrade oils, which will lower the smoke point of that oil. Oils should be stored in dark bottle and stored in a cool pantry in the cupboard. You should store flaxseed and walnut oil in the refrigerator after the bottles have been opened.
Oil that smells of old nut or crayons has degraded and become rancid; dont use rancid oil as it tastes poorly. You can use a thermometer to determine the temperature of the oil. The oil should be stored at least 25 to 50 degrees below its smoke point to avoid health risk.