The area of sensory evaluation is very interesting. Everything we eat or drink that has been prepared in some way has gone through a sensory evaluation process. Olive oil is no different.
As I type this article some country’s contestant is being tasted and judged at the 2011 Los Angeles International Extra Virgin Olive Oil Competition. The judges who make up the tasting panels are trained, some more formally than others, in how to evaluate by using their senses, samples of extra virgin olive oils submitted for the competition. How are they doing this and what are they looking for?
The panelists are looking for indicators in two main areas: positive sensory attributes and negative sensory defects. These attributes and defects can be described through smell, taste, or feel. It may seem strange but seeing is not one of the senses that is used for an EVOO sensory evaluation, in fact, seeing is discouraged. The way it is discouraged is little cobalt blue slightly bowl-shaped glasses are used so the tester doesn’t mistakenly make a taste judgement based on the color of the oil.
The little blue glass is warmed to human body temperature. A plastic lid covers the top of the glass to help warm the oil and trap the aromas. First the taster puts his or her nose in the glass to identify by smell each aroma. Then the taster takes enough oil into his or her mouth making sure the oil covers the tongue, air is then sucked in to oxygenate the oil, and it is swallowed. Attributes and defects that have been detected through smell, taste, and feel from the first smell, to the taste and feel in the mouth, to the smell carried through the mouth to the back of the nose, to the feel at the back of the mouth and throat, are all studiously recorded by the taste panelist. A slice of Granny Smith apple and a drink of plain water and the process begins again.
Here is a list from the International Olive Council’s “Glossary of Olive Tasting Terms” of some of the sensory attributes and defects that panelists are looking for in EVOO:
Positive – Attributes
- Astringent – puckering sensation created by tannins
- Bitter – Characteristic of oil obtained from unripe (green) olives, this is perceived on the back of the tongue. Note that bitterness is an important part of an oil’s balance of flavors.
- Fresh – good aroma, fruity, not oxidized
- Fruity – Set of olfactory sensations characteristic of good (unspoiled) fresh olive fruit, either ripe or unripe. This attribute is perceived by smell, either directly or retro-nasally (back of the nose).
- Green – young, fresh, fruity oil (often mixed with bitter)
- Spicy – bitter cough sensation at the back of the throat
- Green Leaf – A sensation obtained when in the press a small quantity of fresh olive leaves are added. This is a trick which is done to approximate the genuine green taste of green olives.
- Harmonious – All the qualities of the oil blend and work well with each other.
- Hay – dried grass flavor
- Melon – perfumy (ethyl acetate)
- Musky, Nutty, Woody – trace characteristics which are very pleasing when not overpowering
- Pungent – Peppery sensation perceived at back of the throat that is indicative of the oil’s freshness. Also a characteristic of pressing unripe olives.
- Rotund – pasty body which fills and satisfies without aromatic character, always from mature olives
- Soave – characteristic from mature olives
- Sweet – opposite of bitter, stringent or pungent, found in mellow oils
Negative – Defects
- Fusty – Characteristic obtained from olives that were stored in piles prior to pressing, which causes an advanced stage of anaerobic (without oxygen) fermentation.
- Musty – Moldy flavor in oils obtained when a large quantity of the olive fruit has developed fungi and yeast as a result of its being stored in humid conditions for several days. This defect is detected retro-nasally (through the back of the nostrils after swallowing).
- Winey/Vinegary – Flavor that is reminiscent of wine or vinegar. This defect occurs due to aerobic (using oxygen) fermentation in olives which leads to the formation of acetic acid, ethylacetate and ethanol.
- Muddy Sediment – Characteristic of oil that has been left in contact with sediment in tanks and vats. This defect occurs from poor storage conditions after the oil is pressed.
- Metallic – Flavor that is reminiscent of metals. This occurs when the oil has been in prolonged contact with metallic surfaces during crushing. Nowadays it is unusual to find this defect because modern presses are made from stainless steel which does not react with the olives.
- Rancid – Flavor in oils which have undergone oxidation. This is the most common defect; it can occur either before or after bottling and if a bottle, either opened or unopened, has been exposed to light and heat.
- Heated or Burnt – Occurs when oil is exposed to excessive and/or prolonged heat during processing.
- Hay-Wood – Flavor of oil produced from olives that have dried out.
- Greasy – Flavor reminiscent of diesel oil, mineral oil, or mechanical grease.
- Vegetable Water – Flavor acquired by prolonged contact with the vegetable water that is a by-product of pressing olives.
- Brine – Obtained from olives that were brined (such as table olives) before pressing.
- Esparto – Flavor obtained from using new mats made from esparto (a type of grass) when pressing olives.
- Earthy – Flavor obtained from olives with dirt or mud on them that have not been washed prior to pressing.
- Grubby – Flavor obtained from olives that have been attacked by the olive fly, which causes disintegration of the olives before they are harvested.
- Frozen – Flavor obtained from olives that experienced heavy frost or prolonged cold temperatures before being harvested and pressed.
May the sun shine through your branches.