The Oil of Kings
High Quality Extra Virgin Olive Oil in New Zealand
By Margaret Edwards - NZ Sensory Panel Leader
If the New Zealand olive oil industry is to flourish, we must concentrate on producing high quality extra virgin olive oil. This doesn't just happen by chance.
In reality, considerable knowledge, skill and care are required at every stage of production, from growing the trees, harvesting and processing, to storing, bottling and selling the oil.
So, what is high quality New Zealand extra virgin olive oil and what are its characteristics?
Extra Virgin Olive Oil
Everywhere in the world, by definition, extra virgin olive oil must be an entirely natural product.
It is the juice obtained from olives that have been processed mechanically.
Nothing may be added and neither heat nor chemicals may be used at any stage of the process.
Criteria for Extra Virgin Olive Oil
The International Olive Oil Council (IOC) sets the standards for olive oil worldwide.
If olive oil is to be classified as extra virgin, the IOC requires that the oil must undergo both chemical analysis and sensory evaluation.
Under IOC regulations, the chemical analysis for olive oil must be carried out in an accredited laboratory.
Currently no New Zealand laboratories have IOC accreditation. However there are several laboratories recognised by Olives New Zealand that can undertake the tests specified by the IOC. These are tests that check for adulteration (hopefully, never an issue for New Zealand producers) and give an indication of the stability of the oil.
Free fatty acid levels, ultra-violet absorption, and peroxide value indicate the stability. At the time of testing, extra virgin oils must have no more than 0.8% free fatty acid, declared as oleic acid. This is a direct indication of the quality of the oil.
Damage to the fruit while picking, delay between harvesting and processing, and poor processing and storage techniques can lead to an increase in free fatty acid levels.
The level of oxidation that has occurred in the oil is determined by ultra-violet absorption and most commonly, peroxide value (PV).
Although the IOC requires a level of less than 20 milliequivalents of peroxide per kilogram (mEq/kg) of olive oil.
High quality extra virgin olive oils should have a low PV, ideally no more than .5, following processing.
Although not mandatory, other tests that give an indication of quality in an oil include, the fatty acid profile and the assessment of levels of polyphenols, sterols and alcohol components.
A complete nutritional analysis can also be undertaken.
Only the oils that have met the IOC standards for chemical analysis should undergo sensory evaluation.
As with the chemistry, sensory evaluation to assess the status of olive oils must take place in an accredited facility using a panel made up of people selected for their tasting abilities after a screening process.
A panel leader, who must hold the "IOC Supervisor of Virgin Olive Oils Tasting Panels" certificate, is responsible for training the panel to IOC standards.
The oils are always assessed in blind tastings under standardised conditions.
To be classified as extra virgin, oils must be free from any defects (namely fusty, musty, rancid, muddy sediment, winey and 'other') that can arise during processing and storage.
They must also have the positive attribute of fruitiness. While the levels of bitterness and pungency are also noted in the tasting these do not change the status of an oil.
The sensory panel is only responsible for classifying oils and does not comment on their style or differences in flavour.
Currently the Olives New Zealand panel is able to certify New Zealand extra virgin olive oils as it works towards IOC accreditation.
Characteristics of High Quality Extra Virgin Olive Oil
Although all extra virgin olive oils are subjected to the same chemical analysis and sensory evaluation, it does not mean they must or will taste the same. In fact, they all have different characteristics. Many factors will impact on the aroma and flavour of the oil. These include olive variety, soil, climate, and possibly most importantly, time of harvest, and the care taken during harvesting, processing and storage.
There is no 'perfect' oil. Much will depend on personal preference - our likes and dislikes - but there are some well-recognised characteristics that are common to all high quality extra virgin olive oils.
It is important, therefore, for olive oil producers to learn how to taste oils and to recognise the attributes required in high quality extra virgin olive oils, especially when descriptions are needed for bottle labels, the retail trade or consumer tastings.
It takes time and practise to become a proficient taster but if you begin by thinking about the smell and taste of the foods you eat, you begin to build a 'sensory memory' that can then be used when you taste oils. Tasting oils should be done under standard conditions so that you always compare like with like.
The Guidelines For Tasting (see Appendix) should help with this. You should also keep detailed notes describing the oils tasted.
Tasting extra virgin olive oils
We use both our nose and mouth when tasting. Firstly, the aroma (smell) is assessed, followed by the flavour, overall complexity and persistence.
There is no mention of colour, this is because when tasting, colour is not an indicator of quality, an oil with an intense green colour will not necessarily taste better or rate more highly than a golden oil.
For this reason, sensory panels and competition judges taste the oils in blue glasses so that all oils will look the same.
Our noses can tell us a great deal about oils. Fresh oils will usually have a more intense smell than those that are ageing and tiring. The smell should be predominantly of olive fruitiness, very pleasant and enticing. It may also be associated with other familiar smells, for example other fruits (apples, tropical fruits), grass, salad leaves, vegetables, herbs and fresh nuts.
High quality oil will have a balanced aroma with nothing 'jumping out'.
Fresh 'new' oils tend to be at their highest flavour level. As with the aroma, olive fruitiness will be one of the dominant flavours in high quality oil but there could also be flavours that remind you of other fruits (apples, kiwi fruit, citrus or tropical fruits), grass, salad leaves including rocket and watercress, tomatoes, vegetables, herbs and fresh nuts.
As you begin to swallow the oil you may become aware of two more sensations, those of bitterness followed after swallowing by pungency or 'pepperiness'.
Both of these are very acceptable, so long as their levels do not overpower the level of fruitiness, thus making the oil unbalanced.
Overall, the flavour of high quality oils must be well balanced and harmonious.
Complexity and Persistence
Complexity may be broadly defined as an interesting and enticing range of aromas and flavours typical of those expected in extra virgin olive oils.
Complex oils can be described as multi-dimensional.
Persistence is best described as a very pleasant complex, lingering aftertaste.
Both of these characteristics are essential in high quality oils.
Even high quality oils will lose some of their aroma and flavour as they age.
Again, factors such as olive variety, harvest time, processing and storage will impact on the rate at which they diminish.
At this stage of the New Zealand industry only comparatively few styles of extra virgin olive oils are produced, especially when compared with the vast range available in the northern hemisphere. Although from time to time some delicate oils are produced, the majority of our oils are either intense or medium in style. However, there are regional styles emerging, with the oils from the warmer areas of the North Island showing different characteristics from the oils produced in cooler regions.
Typical of oils from cooler regions or cooler years, the fruit for these oils is likely to have been picked when a high percentage has just begun to ripen.
They are full-bodied with complex, robust and intensely fruity aromas, and flavours.
Fruitiness may range from green olive fruity to green apples through to citrus (lime and lemon). Grassiness and/or herbaceous aromas and flavours are to be expected along with bitterness and pungency.
These are typical of oils from moderate to cool regions and will usually have been pressed from a mix of fruit with varying degrees of ripeness from straw through to blush, purple and black.
These oils will be complex and well rounded with moderately intense aromas and flavours. Fruitiness may range from 'green olive fruity' to apples through to tomatoes. Some grassiness and/or herbaceous aromas and flavours are to be expected along with moderate bitterness and pungency.
These oils are similar to oils from warmer olive growing regions. They will usually be seen from warmer areas in New Zealand or when a high proportion of the olives have been picked when fully ripe. These oils are gentle in character and should have good ripe olive fruity aromas and flavours, often with underlying stone fruit or tropical fruit characters. Some oils could have fresh nutty or almond overtones. Although these oils may have very little or no bitterness and pungency, they should be complex and well balanced.
Blended or single varietal oils?
Unlike much of the northern hemisphere where for centuries specific olive varieties have been grown almost exclusively, many New Zealand producers are still experimenting to find the most satisfactory olive varieties.
To date we have limited knowledge of how specific varieties will perform in the longer term in our different climatic regions. Single varietal oils can be of very high quality, but not always. It is often easier to achieve all the desirable attributes of high quality oil by blending so long as you have oils from different varieties available.
Preserving the Quality
Unlike wine, oils, including high quality extra virgin olive oil, do not improve with age and sooner or later become rancid. Ideally, if they are to be enjoyed at their best, most extra virgin olive oils should be used within a year of production.
High quality oils with good levels of polyphenols that help to delay the onset of oxidative rancidity, should retain their quality for up to eighteen months.
Exposure to oxygen causes oil to oxidise. Heat, light, moisture and sediment left in the oil speed up the process, as will contact with some metals, particularly copper, brass, iron and zinc, as they act as catalysts. As oxidative rancidity progresses, undesirable odours and flavours develop in the oil.
Following processing, oil should be placed into scrupulously clean, dry containers and stored airtight (preferably flushed with nitrogen to eliminate oxygen) in a cool place (around 12C) until bottled.
Stainless steel tanks are the containers of choice for bulk oil storage. Avoid contact with copper, brass, zinc or iron.
Ideally, oils are decanted to remove moisture and particles of vegetable matter immediately after processing. If not, once the sediment has settled the clear oil should be removed and placed into clean containers for long-term storage.
Choose packaging that is chemically inert and will protect the oil from air and light. Dark glass bottles and cans are the most suitable.
Use closures (metal screw tops or corks with plastic or wooden tops) that provide an airtight seal.
Ensure storage information, which is a requirement on labels, is adequate; for example, "After use, wipe any oil from the bottle and ensure it is closed properly to minimise contact with air.
Store the oil in a cool dark place, preferably in the refrigerator. The oil becomes thick and cloudy at refrigerator temperatures; this is not harmful and the oil will clear when it returns to room temperature".
A 'best before' date is required on the label. A processing date should be included as well, so that consumers know the age of the oil.
High Quality - Our Future
New Zealand is already producing some award-winning extra virgin olive oils that have won critical acclaim both here and overseas. We will never be bulk suppliers of olive oil our land mass and climate make that impossible, but by concentrating on the production of very high quality Extra Virgin Olive Oil coupled with skilful marketing, we should find a niche in the boutique olive oil markets of the world.
Single Estate Extra Virgin Olive Oil
Is obtained from olives grown on a single Grove which are then pressed or centrifuged and bottled on this Grove, earning the name 'Single Estate'.
Single Estate Extra Virgin Olive Oil is usually the best that is available and can be expected to be expensively priced and if hand harvested is often only available in smaller quantities.
Usually sold on site or in specialty shops, it is stored and displayed away from excessive heat and bright light, which cause deterioration in the flavor and quality of the olive oil.
A Single estate olive oil is also known simply as an Estate Olive Oil.
When you are going to taste olive oils:
Don't smoke, eat or drink anything other than water for at least 30 minutes prior to tasting.
Don't wear / use perfumes, after-shave, hand lotions and strong smelling cosmetics or soap etc that may affect your ability (or that of people near you) to detect aromas.
Prepare the oil/s you want to taste
The ideal temperature for the oil for tasting is 28°C (+ or - 2°C).
If cold, stand the bottles in warm water for a few minutes to increase the temperature of the oils. Pour 15 - 20 mL of oil into a small glass (preferably one without a stem so that you can hold it in the palm of your hand).
Cover the glass (use a glass cover, plastic lid or even a circle of firm cardboard).
Leave the oil/s covered until ready for assessment. Use the same type of glass and cover for each oil.
Sit comfortably in a quiet environment
Assess the aroma
Hold the base of the glass in the palm of your hand and swirl the oil gently. (This helps to warm the oil and release the volatile components.) Lift the lid and take slow deep breaths to evaluate the aroma of the oil. Sniff gently for no longer than 30 seconds.
Evaluate the flavour
Take a small sip (about 3mL of oil).
Distribute the oil around the mouth, then take short successive breaths to draw air in through your mouth.
Close your mouth and breathe out through your nose to allow the volatile compounds to be perceived via the back of your nose.
Swallow the sample or spit it out
Swallowing is optional, although preferable, so that you can assess the levels of bitterness and / or pungency.
Make detailed notes describing the oil/s as you taste them
Note firstly that the oil is or is not free from defects. If defect free, comment on the aromas and flavours you perceive, then the complexity, balance and style.
Clear your palate
Eat a piece of apple and rinse your mouth with soda water or filtered water in between evaluating each oil.
If you are tasting with other people, avoid communicating with them until everyone has finished tasting.