We have been bombarded with messages about saturated fats, trans fats, monounsaturated fats, and polyunsaturated fats to the point of utter confusion. We know that a Mediterranean diet has been shown to be healthy, so we stock our kitchens with large bottles of extravirgin, unrefined olive oil. But is olive oil our best choice? Sometimes.
Although olive oil gets most of the cooking glory, it is not always the right oil for the job. Some oils are indeed healthier than others, but choosing a cooking oil goes far beyond health concerns. Not all oils can be used for all purposes; some are best for high-temperature cooking, whereas others are better for salad dressings and drizzles. Learning to discern the proper oil for the job will help you stock your pantry accordingly.
What Exactly Is Cooking Oil?
We use the generic term vegetable oil to refer to a number of different cooking oils. In truth, oil can be extracted from a variety of sources:
- Nuts (almond, walnut)
- Seeds (sunflower, sesame, safflower)
- Grains (corn)
- Beans (peanut, soy)
- Fruits (olive, avocado, coconut)
Characteristics of Oils
There are many factors to consider when choosing a cooking oil, including flavor and cooking temperature.
Smoke point. Smoke point is the temperature at which an oil begins to smoke—and also the point at which the flavor and the nutritional value of the oil are compromised. Smoke point is a critical factor in choosing the proper oil for the job. The cooking method will determine which oil is most appropriate. If you are searing or frying, you need an oil with a high smoke point, such as grapeseed oil and sunflower oil. Oils with low smoke points, such as olive oil and unrefined walnut oil, are best for low-temperature cooking, like light stir-frying and baking.
Unrefined versus refined Unrefined oil occurs exactly as it does in its plant form—that is, it has not been through any filtering or chemical processes. These oils are simply left in their virgin state after pressing. Unrefined oils are typically richer in flavor and higher in nutrients; however, they also tend to have a lower smoke point than refined oils. Refined oils—oils that have had impurities filtered out—can withstand higher cooking temperatures.
Extraction method. There are many methods for extracting oils from plants and seeds, including the use of chemical solvents and high heat, both of which can damage the structure and the nutritional content of the oil. Most natural oils are extracted without chemicals or heat via one of two methods: expeller pressing or cold pressing.
Expeller pressing is a chemical-free mechanical process that extracts oil from seeds and nuts. There is no external heat applied during expeller pressing. The temperature reached during pressing depends on the hardness of the nut or seed. Harder nuts require more pressure to extract the oil, which in turn creates more friction and higher heat.
Cold pressing better preserves the nuances of flavor in delicate oils. Oils that are cold pressed are expeller pressed in a heat-controlled environment to keep temperatures below 120 degrees F.
Stocking Your Kitchen
Understanding the different characteristics of oils will help you stock your kitchen properly with a variety of oils that serve different purposes. Consider having at least three oils on hand:
- An oil for high-temperature cooking
- An oil for low- to moderate-temperature cooking
- flavorful oil for specialty dishes and dressings
If you really want to get carried away, you can supplement these three oils with a good baking oil and a “finishing” oil, which can be drizzled on completed dishes for some extra flavor and flair.
Most kitchens are stocked with olive oil and canola oil, which are both good and fairly neutral choices. (Canola oil has been steeped in controversy, however, because it is extracted from the genetically modified “rapeseed” and because it is a polyunsaturated oil that may contain trans fats.)
Consider stocking a basic pantry as follows.
Low to moderate smoke point. Olive oil has a moderate smoke point and is a good all-purpose oil. Extravirgin olive oil is best for salad dressings and low-temperature cooking. Avoid frying or roasting with olive oil.
High smoke point. While you may be more familiar with canola oil, grapeseed oil is a light oil with a neutral taste and a high smoke point. It is ideal for high-temperature cooking. Grapeseed is a very basic oil that will likely find its way into more kitchens in the future, especially with the controversy surrounding canola oil. Grapeseed oil also works well for baking, when you want no interfering flavors.
Flavorful oil. Sesame oil is a flavorful oil with a moderately high smoke point. It is good for stir-frying, international dishes, and dressings. If you always stick with basic oils and want to branch out and get a little more adventuresome in the kitchen, sesame oil is an easy place to start!
A Few Facts about Oil
- Oil has a relatively short shelf life (three months to one year) because it can become rancid quickly.
- Exposure to oxygen, heat, and light can diminish the shelf life of oil.
- Refined oils stay fresher longer but may also contain more impurities.
- Dark cooking oils have a shorter shelf life than lighter-colored oils.