Cooking Oils 101
Before choosing cooking oils there are various things to consider including smoke point, taste, and health
When choosing an oil for cooking, it's important to know its “high smoking point", which is the culinary description for the temperature an oil can be heated before it discolors and smokes, both indications of decomposition of the oil and signs that it could create carcinogenic or harmful compounds in your body. You always want to avoid heating oil until it smokes.
Oils with a high smoking point are those that can reach above 400°F. Oils with a greater proportion of monounsaturated and saturated fats are better for high heat cooking. Oils with high polyunsaturated fat content are not suited for high heat cooking as they are susceptible to oxidation; which breaks down the good qualities of the oil and can create harmful compounds.
Examples of oils with high smoking points include: avocado oil (the highest at 520°F), soybean oil (450-495°F), refined safflower oil (450°F), palm oil (446 °F), and refined peanut oil, regular and high oleic sunflower oils (450°F). Rice bran oil, popular in Japanese restaurants, is similar in composition to soybean and peanut oils.
Grapeseed, cottonseed, virgin olive oil, and almond oil have smoking points from 420 to 440°F. Although using extra virgin olive oil (370°F) is not recommended for high heat cooking. Canola oil (rapeseed) has a smoking point of 400°F. Corn oil is popular and inexpensive with a relatively high smoking point (450°F), yet it frequently smokes at lower-than-expected temperatures, so use caution if cooking with corn oil.
Another great oil for cooking is unrefined virgin coconut oil (solid at room temp) (350 °F), which imparts a faint coconut flavor but boasts many health promoting properties. Sesame oil (unrefined 350°F, refined 450°F) are also great for cooking Asian inspired dishes; unrefined sesame oil is also great to add after cooking for wonderful flavor. For dressing a salad, extra virgin olive oil, unrefined flax oil (225°F), avocado, pecan and walnut oil are great choices.
The second criteria to consider when choosing oil for cooking is how does the oil taste and how will it affect the taste of the food. This is purely subjective and personal although most professional chefs have their preferences.
Best for Health?
There is no such thing as the perfect oil, but some are certainly better than others. The proportions of each type of fats is important and opting for those with poly or monounsaturated fats are always the better choices. As for cholesterol, all plant-based oils are naturally cholesterol-free, only animal oils and fats contain cholesterol.
All oils are 100 percent fat and all are high in calories: approximately 120 calories per tablespoon. For sautéing, (pasture raised) butter or olive oil or a combination of the two, are great on the palate and easy on the diet when used judiciously. To be even more cautious, use manual spray bottles of oil to better control the quantity of oils used for cooking.
Storage: Refined oils high in monounsaturated fats can keep their flavor and consistency for a year if kept in the refrigerator. Those high in polyunsaturated should last about six months under refrigeration. Extra virgin and virgin oils can keep their freshness for about a year and do not need refrigeration. Nut oils become rancid quickly; always refrigerate after opening. For most other oils, storage in a cool dark cupboard, away from oven and stove, should suffice. Although the temptation is great to re-use fats and oils, especially the more expensive ones, it's more healthful to use them once and discard any residue.