Buying cooking oil used to be an easy task. You walked into the grocery store, went down the baking aisle, and pulled a bottle from the shelf. There were no options; there was no confusion.

Today, entire aisles are devoted to cooking oil. Oil can come from just about anything, like avocados, almonds, and soybeans. And to add to the confusion, you can get oil flavored with anything from chili peppers to rosemary to lemon.

How do you know which oil is best for your sizzling vegetable stir-fry, perfect pumpkin muffins, or savory balsamic salad dressing? Getting to know a little bit about oil will help you decide which oil is right for your cooking project.

Oil can be made from a variety of sources, such as:

  • Seeds: safflower, sesame, sunflower, seeds from canola plant
  • Nuts: almond, walnut
  • Grains: corn
  • Beans: peanut, soy
  • Fruits: avocado, olive, coconut

The first step in processing is to remove the oil from the seed, nut, grain, bean, or fruit. The extraction process can be chemical or mechanical. When done chemically, the oil source is soaked in a petroleum compound, usually hexane. The oil then requires further refining to remove this toxic solvent. This method is efficient, provides a high yield, and is more common than mechanical extraction.

Mechanical pressing, also called expeller-pressed, uses no chemicals. The oil is derived from its source by squeezing it in a mechanical press. The process can raise the temperature of the oil. Cold pressed means that no additional external heat is added during the processing. Oil purists believe that unrefined, cold pressed oil retains the most flavor, aroma, color, and nutrients.

No matter which oil you choose and no matter what you choose it for, remember to use it in moderation. And in accordance with the American Heart Association's recommendations, opt for an oil high in monounsaturated or polyunsaturated fatty acids.