Chemistry
Guide to Assess the Purity of Olive Oils
The two ways to assess virgin olive, chemical, and organoleptic analysis, are equally important even though one is totally objective, and the other is totally subjective.
Laboratory analysis can tell us about the levels of beneficial polyphenols and oleic acid and the products of deterioration-free fatty acids and peroxide. But it cannot tell us anything about the pleasure to be derived from using fresh, well-made oil.
Organoleptic analysis happens in the nose and mouth of the taster, either professional or you as the end user. Aesthetic notes of fruity, nutty, fresh grassy, peppery, and many, many others are there in varying balances that give complexity to the oil and appeal in different ways to each person. Laboratory analysis can track down the chemical nature of those flavors and aromas, but the human sensory system is still the best organoleptic analysis device. As we will recommend many times on this website, please give yourself the opportunity to taste and assess many olive oils to educate your palate and help you find the oil that gives you the most satisfaction.
Types of Olive Oil
Here are some of the types of olive oil you need to know. For many reasons, olive oil is good for your health. It improves digestive system, prevents cancer, reduces inflammation, and moisturizes hair, etc. However, you need to know that specific types of olive do specific functions. Before you rush to the market to grab a bottle of the oil, you should know about these types.
This oil comes from virgin oil production only, contains no more than 0.8% acidity, and is judged to have a superior taste. Extra Virgin olive oil accounts for less than 10% of oil in many producing countries.
This oil is produced using physical means and no chemical treatment. It has an acidity of less than 2% and is judged to have good taste. Over 50% of the oil produced in the Mediterranean area is of such poor quality that it must be refined to produce an edible product; after these two grades come the blends of oil that are mainly (up to 90%) refined oil and virgin Olive oil.
Oils labeled as Pure olive oil or Olive oil are usually a blend of refined and virgin production oil. Over 50% of the oil produced in the Mediterranean area is of such poor quality that it must be refined to produce an edible product. No solvents were used to extract the oil, but it has been refined with the use of charcoal and other chemical and physical filters.
This oil is a blend of virgin and refined production oil of no more than 1.5% acidity and lacks a strong flavor.
This oil is refined pomace olive production oil, possibly blended with some virgin production oil. It is fit for consumption but may not be described simply as olive oil. Olive-pomace oil is rarely sold at retail; it is often used for certain kinds of cooking in restaurants.
This oil is obtained from virgin olive oils by refining methods that do not lead to alterations in the initial glyceride structure. It has a free acidity, expressed as oleic acid, of not more than 0.3 grams per 100 grams (0.3%), and its other characteristics correspond to those fixed for this category in this standard. This is obtained by refining virgin olive oils, which have a high acidity level and/or organoleptic defects, which are eliminated after refining. Over 50% of the oil produced in the Mediterranean area is of such poor quality that it must be refined to produce an edible product. Note that no solvents have been used to extract the oil, but it has been refined with the use of charcoal and other chemical and physical filters. An obsolete equivalent is “pure olive oil.”
This oil is extracted from the pomace using chemical solvents, mostly hexane and heat. Sometimes blended with some virgin production oil. It is fit for consumption but may not be described simply as olive oil. Olive-pomace oil is rarely sold at retail; it is often used for certain kinds of cooking in restaurants.
This oil is not suitable as food because it is usually made from olives that are spoiled or insect-infested; the term lampante comes from olive oil’s long-standing use in oil-burning lamps. Lampante oil is mostly used in the industrial market. It must be chemically refined before it can be consumed. The resulting oil, after refining, is known as A-Refined, or Refined-A olive oil. It is not, strictly speaking, “olive oil.” It is used as the primary ingredient for a new product that is sold as “Pure Olive Oil.”.
As the United States is not a member, the IOOC retail grades have no legal meaning in that country; terms such as “extra virgin” may be used without legal restrictions.
Since 1948 the U.S. Department of Agriculture (USDA)has listed four grades of olive oil based on acidity, absence of defects, odor, and flavor:[20]
U.S. Grade A or U.S. Fancy possesses a free fatty acid content of not more than 1.4% and is “free from defects.”
U.S. Grade B or U.S. Choice possesses a free fatty acid content of not more than 2.5% and is “reasonably free from defects.”
U.S. Grade C or U.S. Standard possesses a free fatty acid content of not more than 3.0% and is “fairly free from defects.”
U.S. Grade D or U.S. Substandard possesses a free fatty acid content greater than 3.0% and “fails to meet the requirements of U.S. Grade C.”
With these diverse labeling styles and the small amount of information they provide, the best indicator of good olive oil is obtained by tasting while keeping in mind the freshness and beneficial nutritional and antioxidant levels.
