Tasting olive oil is much like tasting wine; it is a pleasurable experience but also part of the official method of grading oil quality.
We only advise tasting fine olive oil, which is FELIPE MATTEI’s way of referring to the very best among olive oils within the Extra Virgin grade as described in What Is Olive Oil.
To taste olive oil, it is advised to use the official olive oil tasting glass which is a concave opaque blue glass. The reason for the opaque blue colour is to hide the olive oil colour as it is not a sign of quality. Some oils are bright green, others golden yellow and some nearly transparent. People tend to think the greener the better (as good oil is made from green olives) however this is not true and the colour should be ignored.
TASTING OLIVE OIL
1 Pour a good amount of oil into a tasting glass and cover the top (using your hand or a small glass plate) to concentrate the aromas
2 Warm up the oil to release all of its volatile components (using your hand by holding the glass from below or a hot plate) but make sure you do not overheat the oil otherwise it will lose all of its positive attributes. The ideal temperature is at about 27 degrees Celsius.
3 Uncover the glass, give it a good swirl and place your nose all the way inside the glass. Keep your mind clear as a white canvas and simply breathe and notice the aromas that pop to mind. Good oil should resemble nature and display a wide array of aromas.
Quite often you will recognise aromas but will be unable to name it. Good scent vocabulary comes with practice and the “olive oil rainbow” on the left helps you with this as it shows common olive oil aromas to be explored, whereas the most frequently found are emphasised with a stronger colour and the least common in a dimmer tone.
4 Take a normal sip of oil but don’t quite swallow it yet, let it run through the mouth and coat your tongue. You will feel the olive oil taste which is exclusively felt by the tongue. It should have some sweetness and bitterness (both positive attributes).
5 With the oil still inside the mouth perform the stripaggio, as the Italians say, which is slurping air rapidly into the mouth to deepen the perception of its aromas. To do so, stretch your mouth (as in a fake smile) and suck air really rapidly through both corners. Keep breathing and a whole range of new aromas will reveal. With this, you are experience the olive oil flavour, which is both taste and smell together (yes, that is the definition of flavour, my friend)
6 Now swallow the oil. Good oil should have pungency, which is a peppery sensation felt at the back of the throat and the more full bodied the oil the more peppery the sensation will be. Good oil should also have a long lasting flavour that keeps coming, sometimes for as long as 30 seconds after you swallow it. Depending on how strong the oil is you may cough and even have a few tears come down your eyes – I told you it was great fun
For those a little more obsessed about olive oil, additional expert knowledge follows
OLIVE OIL ASSESSMENT CRITERIA
There are two ways to assess extra virgin olive oil: subjectively for its organoleptic characteristics with the aid of a professional taster (as described above), or objectively for its chemical composition via laboratory analysis.
The laboratory analysis can indicate the different levels of the compounds that constitute olive oil however the human nose remains the most accurate tool currently available for its assessment.
The assessment of olive oil quality is mostly based around its sensory characteristics. The International Organisation for Standardisation (ISO) defines sensory analysis as the science which uses methods to examine the organoleptic attributes of a product via the sense organs. Accredited olive oil sensory testing laboratories are in line with the ISO 17025 and the EA guide (European Cooperation for Accreditation) for the accreditation of sensory testing laboratories.
In 1992, the International Olive Oil Council (IOC) teamed up with its experts to establish a procedure for grading olive oils. The method is based on:
The method incorporates mathematical formulas (statistics based on median, coefficients of variance and confidence intervals at 95%) in order to exclude any subjective assessment. A taster is used as an instrument for measuring the intensity of perceptions on a continuous scale and the majority of tasters must come to the same assessment.
The IOC trade standards features specifications for each grade of olive and olive pomace oil and its specifications are shared by the Codex Alimentarius. Its guidelines are validated and adopted by the ISO, the International Union of Pure and Applied Chemistry (IUPAC) and the American Oil Chemists’ Society (AOCS). However Australia and New Zealand do not fully agree with the standards set out by the IOC and has not agreed to adopt the limit of 1% for linolenic acid content.
POSITIVE ATTRIBUTES DEFINED
This is the set of olfactory sensations characteristic of the oil that comes from the fresh olive variety, whether ripe or unripe, and it is primarily perceived at the retro-nasal. The 1,2-diacylglycerol (DAG) is the major chemical compound responsible for this attribute and polyphenols have a small contribution. This attribute is often associated with the aroma of green tomatoes, artichoke, green apple, green banana, olive leaves, freshly cut grass, almond and walnut.
This characteristic usually comes in the form of a lingering aftertaste at the back of the tongue. It appears predominantly from the pressing of the unripe olives and from the stone. Polyphenols are predominantly responsible for this attribute followed by DAGs.
This is the peppery sensation that is usually felt at the back of throat when tasting olive oil and is associated with the oil’s spiciness. It appears predominantly from the pressing of unripe olives. Polyphenols are the main compounds responsible for this attribute and DAGs come second.
NEGATIVE ATTRIBUTES DEFINED
Rancidity is the main olive oil off scent that resembles rusted metal. The scent appears as the oil oxidises and secondary oxidation products are formed. The compounds which produce this undesirable characteristic include aldehydes, ketones, acids, alcohols, lactones, furans, hydrocarbons and esters.
Rancidity appears almost immediately in unstable oils when exposed to oxygen (unstable oils are low in polyphenols, or as we casually call them, Light Bodied oils). Consequently, stable oils present strong resistance against oxidation and thus turn rancid very slowly (that is why Full Bodied oils last for longer).
This is the humid, earthy and mouldy flavour in oils. It appears from fruit in where large numbers of fungi have developed as a result of being stored in humid conditions for several days.
This is the fermented flavour that appears in olives that been stored in piles and have undergone advanced stages of aerobic fermentation This negative attribute is predominantly caused by the presence of n-octane, produced by the decomposition of 10-hydroperoxide of oleic acid and isoamyl alcohol formed from fermentation
Ayton, J., Mailer, R.J. and Graham, K. (2012). “The Effect of Storage Conditions on Extra Virgin Olive Oil Quality.” RIRDC publication no. 12/024. A report prepared for the Rural Industries Research and Development Corporation, Canberra.
IOOC, 2012. Designations and definitions of olive oils. [online] Available at: http://www.internationaloliveoil.org/estaticos/view/83-designations-and-definitions-of-olive-oils [Accessed 11 September 2012].
Vossen, P. (2007). “International Olive Council (IOC) and California Trade Standards for Olive Oil.” University of California, Cooperative Extension, US.
Vossen, P., (2007), Olive Oil: History, Production, and Characteristics of the World’s Classic Oils, HortScience, Vol. 42(5).
Wang, S., (2011), “Composite chemical picture of U.S. olive oil: removal of potential trade barriers – year 2”, TASC Project Report, US.