What is the difference between Extra virgin olive oil (EVOO) & Olive oil ? How to use them?
These questions are related to the extraction process of olives into oil and the characteristics of its smoke point .
Generally, olive oil is processed by grinding olives into a paste which is then extracted using a mechanical process by squeezing (traditional method) or centrafugation (modern method). Once olive oil is extracted, there will be the remaining solids called pomace (which still contains a small amount of oil).
Based on its process, the olive oil can be grouped into:
1. Virgin , where oil is produced from a physical process without chemical treatment. Often called cold procces.
2. Refined oil. Furthermore, after going through a cold process , the oil will go through the refinery process, such as chemical processing to neutralize the sharp taste & acid content.
3. Pomace , produced by extraction process using a solvent (usually hexane) with the aid of heat.
Simply, Extra virgin olive oil can be called as the first extract of olives. This oil has a low smoke point because it still contain many unrefined compounds. Extra virgin olive oil will burn at temperatures above 117oC. So Extra virgin olive oil suitable for salad dressings or food served cold.
While Olive oil (the common word for olive oil that has been through a refinery process), has a higher smoke point. So, it could be used for sauteing.
Then, what is a smoke point?
Smoke point shows temperature when the cooking oil/fat will split into glycerol & free fatty acids and produces bluish smoke. This smoke is also a sign of decline in the quality of taste and nutrition content.
Cooking oil which has changed the color to be darker, has a risk as cancer trigger (carsinogenic).
So that, the key of selection on oil/fat for deep fried (fry until submerged) is the higher smoke point, higher than olive oil smoke point. And try to read the nutrition label, especially its saturated fat/trans fatty acids/polyunsaturated fat/monounsaturated fat content.
Further information about saturated fat/trans fatty acids/polyunsaturated fat/ monounsaturated fat, can be read this link.
Wikipedia - Olive Oil
Wikipedia - Cooking Oil
Wikipedia - Smoke Point