Flavor First
Vegetable oil is formulated to be virtually tasteless. Frying french fries in vegetable oil allows potato to come through as the dominant flavor. If you like simple, classic french fries, vegetable oil is the better choice.
Olive oil has a strong, distinctive flavor. French fries fried in olive oil take on a subtle olive flavor. If you enjoy the flavor of olive oil, or are bored with basic french fries, try frying them in olive oil. You might find that french fries are not so boring after all.
The Easy Way Out
Most people fry french fries in various vegetable oils thinking those oils are easier to work with. Some oils have high smoke points, while others are lower than olive oil. The smoke point is the temperature at which the oil undergoes chemical changes that alter its flavor and texture. Essentially, it begins to burn, and foods cooked in oil above its smoke point will take on a burnt flavor.
If you cannot control and monitor the temperature of your oil, vegetable oil, like corn oil, gives you more room for error. The smoke point for corn oil is 453 degrees Fahrenheit. Olive oil's smoke point is 428 F.
Keep in mind the recommended frying temperature for french fries is between 300 and 400 F. This is well below the smoke point of olive oil or vegetable oil.
Healthy Choices
Chances are you probably aren't thinking about making healthy choices when you decide to eat french fries, but your oil choice can make them a little healthier. The health profile of an oil is based on its levels of monounsaturated, polyunsaturated, saturated and trans fats. Saturated and trans fats will raise your cholesterol levels, while monounsaturated and polyunsaturated fats may help lower or maintain healthy cholesterol levels.
Your best source of information on the fat sources in your oil is the nutritional label itself. Vegetable oils from different plants have differing fat profiles, and different styles of olive oil contain more or less of various types of fats.
As an example, corn oil contains 13 percent saturated fat, 29 percent monounsaturated and 58 percent polyunsaturated fat. Olive oil contains 15 percent saturated fat, 75 percent monounsaturated and 10 percent polyunsaturated fat.
Cost Comparison
Most restaurants fry their french fries in vegetable oil because it is significantly less expensive than olive oil. French fries are typically deep fried, which means you will need several quarts of oil, depending on the size of your fry pan or electric fryer. Vegetable oils are readily available and inexpensive in large quantities, but olive oil can get prohibitively expensive.