Oils

Oils

An oil, by definition, is a fat that’s usually liquid at room temperature.  Oils used in cooking are made from vegetables, seeds, nuts, and fruit. Oils are also plant-based and as such contain no cholesterol and are often high in unsaturated fats.  There are a few oils that do contain saturated fat, such as coconut oil, palm oil and palm kernel oil, and are solid at room temperature.

Oils are sensitive to heat, light, and exposure to oxygen and can spoil or turn rancid. Oils should be store in a cool, dry place out of direct sunlight.

One important aspect of fat is its ability to be heated to relatively high temperatures without boiling or otherwise breaking down. This is what allows fried foods to brown and cook quickly. If heated to high enough temperatures, however, fat will begin to break down and an acrid flavor develops, effectively ruining anything cooked in it. The temperature at which this occurs, known as the smoke point, is different for each type of fat. Generally, vegetable oils begin to smoke around 450°F/232°C, while animal fats begin to smoke around 375°F/191°C. Any additional materials in the fat (emulsifiers, preservatives, proteins, carbohydrates) lower the smoke point. Because some breakdown occurs at moderate temperatures and food particles tend to get left in the fat, repeated use of fat also lowers the smoke point.