There are an array of options when it comes to cooking oils. One of the most important factors that needs to be considered when choosing a cooking oil is its resistance to oxidation. Take note that oils can oxidize at both low and high heat. When oils are heated they undergo oxidation quicker, which changes their molecular structure and could turn them into harmful compounds that are dangerous for consumption.
You want to cook with oils that are stable and don’t oxidize or go rancid (spoil) easily. Being aware of the smoke point of an oil will help you determine whether it’s more suitable for cooking on low or high temperatures. As a rule of thumb, the more refined the oil, the higher the smoke point.
The smoke point of an oil or fat is the temperature at which, under defined conditions, enough volatile compounds emerge when a bluish smoke becomes clearly visible from the oil. At this temperature, volatile compounds, such as free fatty acids, and short-chain degradation products of oxidation (causing harm) come up from the oil. These volatile compounds degrade in air to give soot. The smoke point indicates the temperature limit up to which that cooking oil can be used.
Fats and oils that are rich in monounsaturated and saturated fats are much more stable when heated, compared to polyunsaturated fats (source).
Healthy Cooking Oils
Complementing sweet baked dishes and some savoury dishes (such as Thai food), coconut oils offers great health benefits and can liven up a dish with a strong coconutty flavour. In contrast, its flavours can also be masked by other dominating flavours in a dish. Coconut oil is easy to digest, enhances energy, increases metabolism and more.
Coconut oil is approximately 90% saturated fat (which is higher than butter, which is about 64% saturated fat). Harvard Medical School has pointed out that a diet containing too much saturated fat is unhealthy because it increases “bad” LDL cholesterol levels, which raises the risk of heart disease. They recommend using it occasionally.
Refined coconut oil is suitable for occasional high heat cooking such as frying, as it has a higher smoke point, while raw virgin coconut oil is more appropriate for low temperature cooking or baking.
Olive oil is good for low-heat cooking. It is oxidized more readily as the temperatures go up. It also contains enough flavor to be enjoyed uncooked, drizzled over a salad with balsamic vinaigrette, or as part of a marinade for meats. Olive oil is abundant in antioxidants, oleic acid, supports heart health and has been shown to have anti-inflammatory characteristics.
Olives and olive oil offer virtually the same health benefits. The biggest difference is that olive oil is 100% fat, while olives contain only 20% fat.
Tip: It is a proven fact that when exposed to strong overhead fluorescent lights, such as those found in supermarkets across the country, an olive oil packed in a clear glass bottle will be irreparably destroyed in as little as eight hours, having lost its color, flavors and aromas – a tragic fate for even the highest quality olive oil. The container you purchase your olive oil in should be one that retards light.
Olive oil should be stored in a dark, cool place away from the stove, as light and heat are detrimental to it. Look for “100% olive oil” or Extra Virgin Olive Oil on labels to ensure it hasn’t been combined with cheap vegetable oil.
Avocado oil is an edible oil pressed from the fruit of the Persea americana (avocado). As a food oil, it is used as an ingredient in other dishes, and as a cooking oil. It has an unusually high smoke point, both unrefined and especially when refined. The smoke point of the unrefined form is 480 °F (249 °C) and the refined form can reach 520 °F (271 °C).The exact smoke point depends heavily on the quality of refinement and the way the oil has been handled up until reaching store shelves and subsequent kitchens.
Avocado is a great oil to use for cooking because of its high heat tolerance. With a mild, clean flavor and a slight hint of nuttiness, avocado oil doesn’t taste like the fruit. Smooth and light in texture, it also does very well for use as a salad dressing combining it with a variety of balsamic vinaigrette flavors.
Traditionally used in India for ayurvedic cooking, ghee is basically butter cleared of milk solids. Golden in color with a nutty, savory flavor, ghee has a high smoking point and can be used to cook at high heat. The preferred cooking oil in ancient India, ghee was traditionally considered to be the healthiest source of edible fat. Ayurveda says ghee promotes longevity and protects the body from an array of diseases.
If you’re wondering why you shouldn’t just use butter, removing the milk solids from ghee almost entirely removes the carbohydrates and lactose that people are sensitive to. This is the reason why it has a high smoke point, so it can be used for stir frying, deep frying and sautéing.
Understanding Smoke Point
The smoke point correlates with the amount of free fatty acid in an oil. It varies widely depending on origin and refinement. The smoke point of an oil does tend to increase as free fatty acid content decreases and degree of refinement increases. Heating the oil produces free fatty acid and as heating time increases, more free fatty acids are produced, thereby decreasing smoke point. It is one reason not to use the same oil to deep fry more than twice. Free fatty acids equals oxidation. Oxidation is like eating rusted nails.
Get smart about oils, what to use and what to stay away from. Rule of thumb is to keep the cooking temperature below the smoke point. Also, you want to choose good healthy oils instead of products like vegetable shortenings. Learn your oils and cook your heart out!