Olive Oil Grades and Ratings
There are officially nine grades, but you'll also see terms like stone ground, cold pressed, first pressed, raw, unfiltered, organic, premium, and estate or estate blend.
I gathered the following information at the International Olive Oil Council and Sonoma County UCCE website (University of California Cooperative Extension).
The International Olive Oil Council lists the olive oil grades under one of two main categories. They are
1.Olive Oil and 2.Olive-Pomace Oil
The oils must meet certain criteria for each category. They cannot be mixed with any other type of oil, must pass a sensory analysis by a certified panel of tasters, and meet the analytical criteria. The standard indicates all the tests used to determine genuineness and purity as well as the legal requirements for the label.
Olive oil is defined as oil obtained solely from fruit of the olive tree. Virgin oils are extracted only by mechanical means that do not lead to alterations in the oil. The numerical sensory values for each of the first three grades (extra virgin, virgin, and ordinary virgin) come from olive oil ratings by a qualified taste panel that has been officially recognized by the IOOC. The majority of the tasters, usually 5 of 8, must agree statistically on the olive oil ratings indicating the same defect, if any is present and similar intensity for fruitiness, bitterness, and pungency.
1. Olive Oil - These olive oil grades are obtained solely from the fruit of the olive tree and do not include oils extracted using solvents, re-esterification processes or any mixture with oils of other kinds (seed or nut oils). Virgin Olive Oils (first three listed below) are obtained solely by mechanical or physical means under thermal conditions that do not lead to alterations in the oil; using only treatments such as washing, decantation, centrifugation, and filtration.
A: Extra Virgin Olive Oil - This oil has zero defects and greater than zero positive attributes. The majority of the tasters indicated that it is not defective and has some fruitiness. Extra-virgin oil has a free acidity of less than 0.8 % and conforms to all the standards listed in its category. This is the highest quality olive oil grade. Extra virgin olive oil should have clear flavor characteristics that reflect the fruit from which it was made. In relation to the olive variety, fruit maturity, growing region, and extraction technique, extra virgin olive oils can be very different from one another.
B: Virgin Olive Oil - This is oil with a sensory analysis rating from 0 to less than 2.5, a free acidity of less than 2%, and conforms to all the other standards in its category. These are oils with analytical and sensory indices that reflect slightly lower quality than extra virgin olive oil.
C: Ordinary Virgin Olive Oil - Oil with a lower organoleptic (sensory) rating of 2.5 to less than 6.0, a free acidity of less than 3.3%, and conforms to all other standards within its category. It is inferior oil with notable defects and is not permitted to be bottled under European Union (EU) laws, so it is sent for refining. The EU has eliminated this category and other regulating agencies are likely to follow. It will simply be absorbed into the lampante category.
D: Lampante Oil - Oil with severe defects (greater than 6.0) or free acidity of greater than 3.3%, and meets with the other standards in its category. It is not fit for human consumption and must be refined. These olive oil grades come from bad fruit or from improper handling and processing.
E: Refined Olive Oil - Oil obtained from virgin oils by refining methods that do not alter the initial glyceride structure. It has a free acidity of less than 0.3 % and must conform to the other standards within its category. The origin of refined olive oil must not come from the solvent extraction of pomace. The refining process usually consists of treating bad virgin oil/lampante with sodium hydroxide to neutralize the free acidity, washing, drying, odor removal, color removal, and filtration. In the process, the oil can be heated to as high as 430oF (220oC) under a vacuum to remove all of the volatile components. Refined olive oil is usually odorless, tasteless, and colorless. It is not fit for human consumption in many countries including the EU.
F: Olive Oil - Oils that are a blend of refined and unrefined virgin oils. It must have a free acidity of not more than 1% and conform to the other standards within its category. This grade of oil actually represents the bulk of the oil sold on the world market to the consumer. Blends are made in proportions to create specific styles and prices. Olive oil grades in the US labeled as “Extra Light” would most likely be a blend dominated by refined olive oil. Other blends with more color and flavor would contain more virgin or extra virgin olive oil.
2.Olive-Pomace Oil - Oil obtained by treating olive pomace with solvents. It does not include oils obtained in the re-esterification processes or any mixture with oils of other kinds (seed or nut oils).
A: Crude Olive-Pomace Oil - This is the solvent extracted crude oil product as it comes out of the pomace extractor after distillation to separate and recover most of the solvent. EU law also defines any oil containing 300-350 mg/kg of waxes and aliphatic alcohols above 350 mg/kg to be crude pomace oil. It is not fit for human consumption, but is intended for refining.
B: Refined Olive -Pomace Oil- Oil obtained from crude pomace oil by refining methods that do not alter the initial glyceride structure. It has a free acidity of not more than 0.3% and its other characteristics conform to the category standard. Refining includes the same methods used for “refined olive oil” except that the source of the raw product comes from pomace by means of solvent extraction. It is not fit for human consumption in many countries and under EU laws.
C: Olive-Pomace Oil - A blend of refined olive-pomace oil and virgin olive oil that is fit for human consumption. It has a free acidity of not more than 1% and must conform to the other standards within its category. In no case shall this blend be called “olive oil.”
USDA olive oil grade standards