Olive oil is extracted by first crushing the fruit, then pressing the paste and lastly separating the oil from the liquor. The resulting oil is classed into four possible categories (as designated by the International Olive Oil Council or IOOC), depending on the process used to extract and refine the oil.
1. Extra light
This is a refined oil, light in colour, aroma and taste, but it is not light in kilojoules, having the same number as the other types of oil, 485kJ (115 calories) per tablespoon. This is a good starting point if you want only a hint of olive taste.
Extra light olive oil is perfect for making cakes, biscuits, pastry desserts, greasing tins or whenever you want only a little olive flavour.
2. Olive oil
Made from a blend of refined oil and some extra virgin oil, resulting in a mild olive flavour, this is the most commonly used olive oil worldwide. It is sometimes called 100 per cent pure olive oil, though this term is being used less and less. Colour can vary from deep golden yellow to green, depending on the ripeness of the olives crushed. This is no indication of quality and a matter of personal preference, the greener oil often having a peppery bite, especially on the back of the throat.
An all purpose oil used in salad dressings, mayonnaise, pan-frying, stir-frying and deep-frying.
3. Unfiltered extra virgin
Sometimes called raw olive oil, this is thicker, cloudier and richer in flavour than extra virgin olive oil. It contains all the nutrients found in the olive fruit. Ideally, this should be used up fairly quickly.
4. Extra virgin
Is made from olives in excellent condition, crushed as soon as possible after harvest and processed without the use of high heat, maintaining the flavour, aroma and vitamins of the olive fruit unchanged. These oils are sometimes called "cold pressed" or "first cold pressed", but these terms are being phased out, as pressing is often replaced by centrifugation. To be allowed to be called Extra Virgin, the oil must be faultless, with perfect taste and aroma, and oleic acid (an indication of quality) of no more than 1 per cent. Extra virgin is the top of the range in terms of fruity olive flavour and is usually the most expensive.
Although extra virgin olive oil is suitable for cooking and even deep-frying, due to its cost, many people prefer to save it for salad dressings and for finishing off dishes where the oil is added after cooking.
See Recipe Finder's article Tips on using olive oil