OLIVE OIL QUALITIES
Olive oil grading follows international quality standards according to the method of production, the level of acidity and basic organic characteristics. Special testers check the taste and smell of an oil. Taste and smill, in connection with colour, are the three areas checked by international testers in assessing the quality level of a product. Fluidity and a harmonious – balanced relationship between the characteristics of the oil, are used to form a final evaluation.
Colour does not always prove the quality of an oil. A good oil can be from green to golden yellow. It can even seem cloudy if it has not settled yet. As colour is not a sure sign of quality, experts test olive oil in dark blue and not transparent glasses. The colour of the product depends on the main substances of the olive fruit that the oil has been made from. If chlorophyll is the main factor, then the oil will lean more towards the colour green. If carotene is the main substance, then the oil will be more golden yellow. Olives which are gathered at the beginning of the harvesting period, usually produce oil of a greener colour, due to the chlorophyll they contain.
Taste and smell
Olive oil reminiscent of the scent either of fruit or of oil fresh from pressing is believed to be excellent. This is the same with wine as testers try to pinpoint pleasant smells which remind them of other products, such as fruit, like apples or nuts, etc.
A bitter or slightly bitter taste shows that the olives used were not ripe when picked. A pleasant smell and taste can also be put down to the area in which the olives grew and the way they were cultivated. A fruit taste comes from ripe olives which have balanced characteristics. Olive oil with an unpleasant smell and taste is better avoided. Smelling soil or mould down-grade a product. It can be seen then that experience is needed for someone to safely assess an oil.
The degree of acidity in oilive oil indicates the oleic acid content. It is believed to be edible, according to the International Olive Oil Council, when the acidity does not exceed 3.3 degrees (content of oleic acid 3.3%). In reality, olive oil which has an acidity level of no more than one is much better. You should always read the label on an olive oil bottle to see the degree of the acidity. In Greece, there is excellent olive oil with acidity less than 0.5 degrees! The degree of acidity greatly affects the taste.
Oxidization (rancidity) is one of the most important causes of spoiling olive oil. Conditions of storage (light, oxygen etc) help oxidization. This is easily spotted by a tester without scientific tests, as the taste is badly affected by oxidization. Olive oil producers can distinguish good quality from rancid oil, after years of experience. As they say, “the oil got rancid and smells like soil”. On Crete, they identify the smell of rancid olive oil with the smell of soil. Similarly, at Kalavryta of the Peloponnese they say “the oil is not good because it nips the tongue.”
Oxidization reduces or destroys the basic components in olive oil, especially those which are unique to this produce, in contrast to all the other fat substances. It can destroy the fat-soluble vitamins or the fatty acids such as linoleic and linolenic but it can also produce substances which are dangerous for the human body.