When shopping for cooking oil, you've probably stared at the vast array of oils on the shelves and wondered which was best for the dish you're making and what the actual differences are between them. And when something is labeled vegetable oil, what exactly does that mean? Which option would be the best for frying and how do you store them all so they don't go rancid. Below you'll find a discussion of the different types of common cooking oils and the proper use of each one.

Vegetable Oil

Vegetable oil is probably the most commonly used and frequently called for in recipes that require frying because it has a relatively high smoke point. Vegetable oil is actually a blend of several oils, such as corn, soybean, palm, and sunflower.

Canola Oil

Canola oil is widely considered to be a healthier oil because of its low saturated fat content and high monounsaturated fat. It is commonly used in frying at medium-high temperatures, up to about 450 degrees F.

Corn Oil

Corn oil is relatively low in both saturated and monounsaturated fats. It is a popular ingredient in margarine and used in both frying and baking. As with canola oil, corn oil should only be used when frying at medium-high temperatures, up to about 450 degrees F.

Sunflower Oil

Sunflower oil is low in saturated fat and high in vitamin E. Many food manufacturers are recognizing the health benefits of sunflower oil and are using it as the preferred oil in such snack foods as potato chips. It can be used at home to fry, cook, and as the oil in salad dressings.

Olive Oil

There are different varieties of olive oil: extra virgin, virgin, extra light, and refined. Extra virgin olive oil is the most common of those used. There are many uses for all varieties, such as stir-frying, cooking, sautéing and using as an ingredient in recipes. Olive oil is also frequently used in salad oils. It is the healthiest of all the oils as it is high in monounsaturated fat which has been shown to help reduce the risk of heart disease. Many people use it daily in their meals, drizzling it over a wide variety of foods. As a cooking oil, it tends to have a lower smoke point and should be used when frying at low or medium high temperatures.

Peanut Oil

Peanut oil is a great oil to use when frying in very high temperatures. For that reason, it is a common oil during the Thanksgiving holiday as many people use it in their turkey fryers. But it's also great for frying anything, such as fried chicken or French fried potatoes.

Oil Flavors

In addition to health and temperature variations, consider if the flavor of the oil will suit your recipe. Most oils such as vegetable, canola, etc. are relatively flavorless and will not impact the taste of your food. Olive oil, however, has a much more pronounced taste, especially the virgin and extra virgin varieties. If you like the olive flavor and you're cooking a savory recipe, go ahead and use it. But when cooking or frying sweet treats such as doughnuts, it's probably best to choose an oil with a more subtle flavor.

Storing Oil

All oils remain liquid when kept at room temperature so it is best to store oil in a dark, dry place, such as your pantry. Oils that are high in monounsaturated fat will keep up to a year, while refined olive oil, having the highest of monounsaturated fat, can last a few years. Extra virgin and virgin olive oils will keep about a year after opened. The shelf life of most other oils after opened is usually six-eight months. Before using older oil, simply give it a sniff. You'll be able to tell easily if it's gone rancid and should be discarded. Otherwise, it will impart that rancid flavor and aroma to the food.

Another important fact to note is how to properly discard used cooking oil. It should never be poured down your kitchen sink because oil can congeal and block your pipes. The best way to discard it is to pour it into a leak-proof container and throw it out with the rest of your garbage.