Updated February 19th 2021
Extra Virgin Olive Oil : What Factors Determine The Taste
High quality extra virgin olive oil is like fine wine, there is an incredibly wide choice and taste. Each olive oil has its own unique taste characteristics depending on the type of olive or varietal the olive oil comes from, the soil conditions where the olive trees are grown, when the olives are harvested, how the olives are treated during the harvesting and pressing to produce the olive oil and a whole host of other factors.
For example, oil made from predominantly unripe (green) olives contain flavours described as grassy, artichoke, or tomato leaf, whereas riper olives tend to yield softer flavours often described as buttery, floral, or tropical.
The above descriptions are associated with high quality, extra virgin olive, but trained tasters also learn to identify negative characteristics. Flavour defects in olive oil are associated with problems with the olive fruit (olive fly, frozen conditions), improper handling of olives during harvest (dirt, wet fruit, prolonged storage prior to milling), certain milling conditions (unsanitary equipment, excessive heat), and improper or prolonged storage after milling (oxidation).
An olive oil that is determined to have flavour defects is not of genuine extra virgin quality. According to the International Olive Council extra virgin olive oil must meet both chemical and organoleptic (flavour) standards that include the absence of flavour defects.
The first step in learning how to taste olive oil is to understand how our senses work. Perception of flavour relies on both our senses of taste and smell. The ability to taste is quite limited; receptors on our tongue can only discern sweet, salt, sour, bitter, and umami (the flavour of protein). All other information that we think of as flavour is actually perceived by smelling food through the back of our nostrils (retro-nasally) while it is in our mouths. To illustrate this fact, think about how little flavour we perceive when we have a cold (or indeed now Covid!). This is because one cannot smell food retro-nasally when one’s nose is stuffed up.
Tasting Olive Oil
When tasting extra virgin olive oil, much of the olive oil’s characteristics are perceived through the sense of smell. Though most people enjoy olive oil with other foods, the following steps allow us to focus on the olive oil’s flavour without distraction:
- Pour a small amount of olive oil (about 1 tablespoon) into a small tapered (wine) glass.
- Hold the glass in one hand and use your other hand to cover the glass while swirling the olive oil to release its aroma.
- Uncover the glass and inhale deeply from the top of the glass. Think about whether the aroma is mild or strong. You may want to write down descriptions of the aromas that you detect at this point.
- Next you slurp the olive oil. This is done by sipping a small amount of olive oil into your mouth while “sipping” some air as well. (When done correctly, you will make that impolite noise that would cause you to be scolded when you were a child!) Slurping emulsifies the olive oil with air that helps to spread it throughout your mouth, giving you the chance to savour every nuance of flavour with just a small sip of oil.
- Finish by swallowing the olive oil and noticing if it leaves a stinging sensation in your throat.
Each of the above actions focuses our attention on a specific positive attribute in the olive oil. Firstly, we evaluate the olive fruit aroma (fruitiness) by inhaling from the glass. When the olive oil is in our mouth, we further evaluate the aroma retro-nasally as well as determine amount of bitterness on our tongues. Lastly, we determine the intensity of the olive oil’s pungency in our throats as we swallow it.
Does The Colour Matter?
The olive oil colour is not addressed during sensory assessment. The reason is that contrary to the common belief that golden olive oil is mild and dark green olive oil is robust, colour is NOT an indicator of either the olive oil’s flavour or quality. In fact, in scientific assessments, we sample from specially designed blue glasses that obscure the colour of the olive oil. Tasting from a dark glass prevents us from having preconceptions about the flavour of the olive oil before we actually smell or taste it.
Practice Tasting Olive Oil
Once you are comfortable with the above tasting method, try the following exercise. Select three olive oils labelled as extra virgin olive oil, including an inexpensive imported brand from the supermarket. In between samples, clean your palate by eating a small piece of tart, green apple and then rinsing your mouth with water.
Consider the following as you evaluate each olive oil sample:
- Is the aroma of the olive oil pleasant or unpleasant?
- Is the olive oil aroma mild, strong, or somewhere in the middle (we’ll call that medium)? When assessing the second and third olive oils, note if the aroma’s intensity is weaker or stronger than the previous sample.
- Note 3 words (or phrases) that describe the aroma.
- Is the olive oil bitter, which is primarily sensed towards the back of the tongue? Would you describe the bitterness of the olive oil as mild, medium or strong? Is the intensity of the olive oil’s bitterness in balance with the intensity of the aroma?
- When you swallow the olive oil, how does it feel in your throat? Did the oil leave a mild impression, or did it sting your throat or make you cough? Is the intensity of the oil’s pungency in balance with the olive oil’s aroma and bitterness?
When you have completed the above exercise, take a few moments to review your notes. What were the characteristics that you enjoyed the most? Were there any characteristics of the olive oil that you didn’t enjoy? How did the supermarket brand compare to the other olive oils? Even without an experienced taster sharing their thoughts about the olive oils with you, there is much you can learn by tasting olive oils on your own.
Using this same tasting method, you can sample another set of oils on another day, and still be able to compare your responses to the first set; this is how we build our personal olive oil “vocabulary”. You will begin to recognize flavours and may even discover which varietals produce the flavours you prefer.
You will learn to compare the level of intensity for fruity aroma, bitterness and pungency, and will begin to identify olive oils as mild, medium and robust (intense). It’s a good idea to organize your tasting notes in a binder so you can review your past tasting experiences with new ones.
Taste is personal, so not everyone will agree on which varietals, and other factors, produce the best olive oil. However, tasting oils in a methodical fashion will help to educate your palate, and you will be able to select oils with flavour characteristics that you enjoy and enhance your meals. Here is a list of terms commonly used to define olive oil taste, positive and negative. All used in tasting olive oil.
Positive Attributes : Extra Virgin Olive Oil
Apple/Green Apple: indicative of certain olive varietals
Almond: nutty (fresh not oxidized)
Artichoke: green flavor
Astringent: puckering sensation in mouth created by tannins; often associated with bitter, robust oils
Banana: ripe and unripe banana fruit
Bitter: considered a positive attribute because it is indicative of fresh olive fruit
Buttery: creamy, smooth sensation on palate
Eucalyptus: aroma of specific olive varietals
Floral: perfume/aroma of flowers
Forest: fresh aroma reminiscent of forest floor, NOT dirty
Fresh: good aroma, fruity, not oxidixed
Fruity: refers to the aroma of fresh olive fruit, which is perceived through the nostrils and retro-nasally when the oil is in one’s mouth.
Grass: the aroma of fresh-cut (mowed) grass
Green/Greenly: aroma/flavor of unripe olives
Green Tea: characteristic of some unripe olive varieties
Harmonious: balance among the oil’s characteristics with none overpowering the others
Hay/Straw: dried grass flavor
Herbaceous: unripe olive fruit reminiscent of fresh green herbs
Melon: indicative of certain olive varietals
Mint: indicative of certain olive varietals
Pear: indicative of certain olive varietals
Peach: indicative of certain olive varietals
Peppery: stinging sensation in the throat which can force a cough (see pungent)
Pungent: stinging sensation in the throat which can force a cough (see peppery)
Ripely: aroma/flavor of ripe olive fruit
Round/Rotund: a balanced, mouth-filling sensation of harmonious flavors
Spice: aroma/flavor of seasonings such as cinnamon, allspice (but not herbs or pepper)
Sweet: characteristic of mild oils
Tomato Leaf: indicative of certain olive varietals
Tropical: indicative of ripe olive fruit with nuances of melon, mango, and coconut
Walnut Shell: nutty (fresh not oxidized)
Wheatgrass: strong flavor of some green olive fruit
Woody: indicative of olive varietals with large pits
Negative Attributes : Non-Extra Virgin Olive Oil
Acetone: aroma of nail polish remover, associated with winey defect
Blue Cheese: aroma associated with muddy sediment defect
Brine: salty taste indicating that oil was made from brined olives
Bacon: smoky essence that may indicate oxidation
Burnt/Heated: caused by processing at too high a temperature
Cucumber: off flavour from prolonged storage, particularly in tin
Dirty: oils which have absorbed unpleasant odours and flavours of dirty waste water during milling
Dreggish: odour of warm lubricating oil caused by the poor execution of the decanting process
Esparto: refers to straw-like material in mats occasionally used in older mills that may create a hemp-like flavour in oil
Fiscolo: refers to coconut fibers in mats occasionally used in older mills that may create a hemp-like flavour in oil
Flat/Bland: oils which have no positive or negative aroma or flavour characteristic of olive oil; may indicate presence of refined olive oil
Frozen/Wet Wood: sweet, dry, and untypical aroma/flavour derived from olives which have been exposed to freezing temperatures
Fusty: anaerobic fermentation that occurs when olives are stored in piles too long before milling
Greasy: flavour of diesel or gasoline caused by equipment problems
Grubby: flavour imparted to oil by olive fly damage to olives
Hay-wood: flavour of dried olives
Muddy Sediment: barnyard-like aroma caused by olives’ prolonged contact with dirt before or after milling
Musty: moldy, humid flavour created by wet olives that have been stored too long before pressing
Metallic: oils that have had prolonged contact with reactive metal surfaces either during processing or storage
Rancid: the flavour of oxidation that occurs as the oil ages, often described as “stale nuts”
Rough: pasty, thick, greasy mouth feel
Sour Milk: aroma associated with muddy sediment defect
Stale Nuts: flavour of oxidized oils, rancidity
Unbalanced: oils with overwhelming flavours of bitterness and pungency
Vegetable Water: oils that have been stored in contact with the water content of the olive after processing
Winey: sour/vinegary flavour caused by aerobic fermentation of olives during processing (see vinegary)
Vinegary: sour/vinegary flavor caused by aerobic fermentation of olives during processing. (see winey)
Yeasty: aroma of bread dough; associated with winey defect