Cooking oils originate from a variety of sources ranging from avocados to peanuts. They are “refined” for use in high-heat frying or sauteeing, as opposed to unrefined oils, which are typically used in salad dressings and sauces.

Fried foods retain moisture but repel much of the grease in very hot oils. It is important to understand which types have the highest smoke points. This is the highest temperature an oil can reach before becoming combustible (the flash point followed by the fire point).

Varieties

Common types of refined cooking oils and their smoke points:

Canola: This oil tops the list for its healthful benefits. It has little or no trans fats and is loaded with the “good” fats (monounsaturated/polyunsaturated). It also is among the most bland, which means no taste is imparted to foods. Heat to 375ºF.

Corn: High in Omega-6 fatty acids and has little flavor. Heat to 400ºF.

Olive: Also very heart healthy as it’s high in monounsaturated fats. Extra-virgin oil can be heated to 230ºF-350ºF. Extra-light versions have a much higher smoke point (460ºF).

Peanut: It can be heated to 450ºF and is the oil of choice for outdoor deep-frying. It also is fairly tasteless, but some report that there is a “taste” that transfers to foods. Chinese brands may have more taste as well. People with sensitivity to peanuts should not use this oil.

Safflower: Not as nutritious as other types, but has a high heat level of 450ºF-510ºF.

Soybean: Healthy and economical; one of the most popular oils. Reaches temperature of 450ºF and also used for baking. In fact, the majority of products that list “vegetable oil” contain this type.

Other specialty oils recommended for deep-frying include avocado (520ºF), almond (495ºF), and walnut (400º). These can be found at health food stores and ethnic or gourmet markets.

Buying Tips

• Pure (100%) vegetable oils can be used for higher-temperature cooking than oil blends.

• Always read the labels, especially on generic brands.

Storage Tips

• Keep cooking oils airtight and in a cool dark spot.

• Oils can be refrigerated, but will turn cloudy. Return to room temperature to regain clarity.

• The type of fat content will determine how long an oil can be kept. Those containing monounsaturated fats will be good for at least twelve months, but oils with polyunsaturated fats will only be usable for about half that time.