The chemistry of healthy cooking oils
The use of plant oils rather than lard, butter and other animal-based fats universally eliminates the saturated fat that we would otherwise consume. The way that the human body processes saturated fats ends up forcing the body to build its own low-density cholesterol, so avoiding these types of fats is an exceptionally good idea. With this in mind, not all plants are created equal. Neither are the various oils made by pressing these plants.
Vegetable and plant oils are liquid at room temperature, because unsaturated fats have a lower melting point than saturated fats. The reason for this is chemical. Saturated fat is called saturated, because every carbon-carbon double bond along the spine of the fat molecule has had all of its double bonds removed and a number of hydrogen atoms added. Simply enough, it’s totally saturated with hydrogen. Though normally perfectly safe to consume, vegetable oils can be chemically converted to saturated fats through a process known as hydrogenation, literally the addition of hydrogen to the fat. If this process is done part way so that only some of the double bonds have been saturated, we end up with partially hydrogenated oils, also known as trans fats. Keep an eye out for hydrogenated and partially hydrogenated vegetable oils on the ingredient lists of foods. They’re just as bad as, if not worse than, animal fats.
Smoke Points and Flavor: The Heart of the Cooking Oil Search
When purchasing straight plant oils, there are two primary factors to consider. First, every oil will taste different. Second, each oil has a different smoke point, the temperature at which theoil will begin to smoke, sputter and denature into something decidedly less than delicious. These two properties influence how each oil is to be used.
A number of popular oils, a description of their flavors, and their smoke points are listed below.
- Best used when stir frying, almond oil tastes much like the parent nut. Its smoke point is at approximately 420°F.
- Similar in flavor to olive oil, avocado oil is best used in stir frying, searing and other applications that require a high temperature. With a smoke point of 520°F, avocado oil is among the most robust plant oils on the planet.
- Olive oil has a rich, light-bodied taste and has a wide range of applications due to the pressing system placed upon the oil. Extra virgin olive oil has a smoke point of about 320°F, while progressive pressings each have a higher smoke point than the one before it. For its part, extra light olive oil has a smoke point of 468°F.
- Sesame oil has two styles: a light and nutty Middle Eastern variety and a dark and toasted Asian variety. Though a tasty addition to any skillet cooking up meats, it is also a superlative salad dressing base. Its smoke point is at 410°F.
The various cooking oils present on the market each have their own quirks working for them. Varying flavors, smoke points and fat profiles bring about a myriad of uses that the savvy consumer should always stay abreast of.
Bear in mind, however, that plant oils can be corrupted by modern industrial processes. Partially hydrogenated and hydrogenated vegetable oils are, in the end, no better for the consumer than animal fats and defeat the purpose of plant oils in the first place. By applying due diligence, however, the savvy consumer can enjoy these various oils without sacrificing health to do it.