Making a quality EVO
Understanding the production methods for extra-virgin olive oil is fundamental for becoming informed consumers. Extra-virgin olive oil is made by pressing the olive fruit and not by extraction of fat from a seed, as happens with vegetable oils like sunflower, corn and peanut. This is an essential difference because the mission of the fruit is to defend the seed through polyphenols and other substances. By pressing the fruit, all these micronutrients are saved in the oil and then protect the body of the consumer. If you’re curious and want to find out how extra-virgin olive oil is made, keep reading!
The veraison or olive maturity index indicates how ripe the fruit is by assessing the changes in the colour of the olive fruit, known as the drupe. The most appropriate veraison index for starting harvest is that which will ensure the best balance for amounts and sensory profile of olive oil obtained. The veraison index varies according to the geographical area and olive cultivar grown. In the case of some oils, the fruit should be harvested when the drupe skin is green to yellow; in other cases, when it is reddish or pale purple; in yet others, when it is black. This is another reason why the colour of an oil may be greenish or yellowish without the quality being affected in any way.
In order to obtain a good extra-virgin olive oil, the olives must absolutely be picked directly from the tree. If the drupes fall to the ground it means they are too ripe and will also be contaminated by contact with the ground, which means the oil made will be of poor quality. Olives may be picked manually or using mechanical devices. Manual picking systems are by hand or with the help of combs and rollers, and beating, a system whereby the branches are tapped with poles so the olives fall onto nets arranged around the base of the tree. Then there is shaking, a mechanical method using a mechanical shaker, which vibrates against the tree trunk and branches, causing the olives to fall.
Pressing or extraction
After harvesting, it is important to keep the olives in a ventilated place, and proceed to extraction of the oil within 24 hours, to avoid spoiling of the fruit and excessive acidity in the oil itself. Olive pressing facilities may use a traditional pressure system, or a more modern centrifuge extraction.
In the former, after a quick removal of twigs and impurities, the olives are ground into a paste by granite wheels. The olive paste is then moved onto round nylon pressing mats, then crushed by a hydraulic press, which separates the oil and water from the pomace oil. The olive oil is then separated from the water by a centrifuge.
The traditional method, however, is no longer sufficient for meeting hygiene and quality requirements defined by today’s oil-making industry, and is thus gradually being replaced by the centrifuge extraction method, which uses state-of-the-art continuous-cycle systems.
In the latter, the olives are vacuumed to remove twigs and leaves, then washed to remove soil and other impurities. Clean olives are thus processed to make a smooth paste using a hammer crusher. The next step is in a malaxer, a steel tank with helical blades that turn and coalesce droplets of oil into increasingly large drops. The final paste is then sent to a powerful horizontal centrifuge which separates the oil from the pomace and vegetation liquid.
The benefits of olive oil
For some time now, research has shown that olive oil is the healthiest and easiest to digest of all comestible types on sale. In addition to a high content of monounsaturated fatty acids, olive oil contains antioxidant phenolic agents, responsible for the pungent and bitter notes, and which counteract the harmful effects of free radicals and cellular aging. It is scientifically proven that in Mediterranean countries where olive oil is the quintessential condiment, the incidence of cardiovascular disease is extremely low and life expectancy is quite high. Indeed, olive oil is a foodstuff with unique nutritional characteristics which, in turn, provide many beneficial effects for our organism. Let’s look at a few of them:
And the best choice for frying
When subjected to high temperatures in the presence of oxygen, oils undergo an acceleration of oxidation phenomena. Each oil has a maximum tolerance temperature called the “smoke point” beyond which it begins to decompose, producing substances that are very damaging for the body.
Of the three types of fat that make up an oil (saturated, monounsaturated, polyunsaturated), polyunsaturated have the most unstable bonds, and lowest resistance to the action of heat. As a result, oils with a high percentage of polyunsaturated fats are to be avoided for frying.
Olive oil contains just 9% of polyunsaturated fat and has a critical temperature of 230 °C, far above the ideal temperature for frying (180 °C – 190 °C). Conversely, coconut oil (177 °C), sunflower oil (160 °C), soy oil (130 °C), corn oil (160 °C), margarine (150 °C), and butter (110 °C) have a lower critical temperature than frying temperature, and therefore pose higher risks in cuisine.
Olive oil, however, is made up mainly of monounsaturated fats (76%) and contains a very low percentage of saturated fats (15%). For this reason, it is healthier and more stable, so is by far the best choice for frying too. In tests, it was found that olive oil can be used up to six consecutive times for frying before it begins to decompose.
Extra-virgin olive oil has a slightly higher smoke point than olive oil but culinary experts still prefer to use olive oil for frying because the intense flavour of EVO might overwhelm that of the foodstuff being cooked, and the result might seem less crisp.
Beyond the table
Olive oil is a healthy, nutritious and tasty foodstuff, but it can also be an unexpected solution in applications that are quite distinct from its nutritional use.
GOils made from pressed olives present naturally varied shades of colour, ranging from intense to pale green, golden reflections tending to yellow. This depends on a variety of factors, such as the cultivars and the place of origin, the ripeness of the drupes, or the type of extraction equipment used.
For all these reasons, the colour cannot be considered a factor that influences olive oil quality. Indeed, we know that when tasting, professionals use dark-coloured glasses to prevent the hue of the oil influencing their judgement.
The only case in which a colour variation points to actual lack of quality is when the oil has reddish tinges, because it indicates the oil has deteriorated. If exposed to heat or direct light, the chlorophyll naturally contained in extra-virgin olive oil decomposes, turning from green to brown and giving the oil a reddish colour, which accompanies sensory degradation.
Oil is usually bottled in dark green bottles to protect it from the light. Similarly, olive oil should be stored in cool, dry places.
Clarity and consistency
All extra-virgin olive oils are cloudy at origin because when just pressed they retain traces of humidity and pulp residue. Over time, excess moisture separates from the oil emulsion, settling on the bottom of the bottle and giving rise to typical sediment.
The sediment can be removed using a mechanical process that does not alter the characteristics of the oil. Filtration thus makes it possible to avoid oxidation and fermentation caused by contact with water, preserving the oil’s flavour and fragrance for a far longer time. That is why Pantaleo filters all its oils, with the exception of special selections for immediate consumption.
Several of our top EVOs – for instance Selezione Oro – are made from prized Italian oils and are simply left to settle, which keeps intact the aroma of the just-picked olives. For this reason these oils may have sediment on the bottom. In this case, we recommend consuming the EVO as quickly as possible.
If there happen to be solid curds inside the oil (they look like butterflies or very pale cotton wool) indicates that the liquid has been kept at a very low temperature and has frozen. This does not impact the quality of the oil in any way, and confirms that it is best kept “away from sources of heat”. Once back in a warm kitchen, the oil returns to its usual fluid consistency.
Each extra-virgin olive oil offers specific palate and nose sensations that are key to its character. These sensations overall create the flavour of the foodstuff. To assess the flavour of an oil, there is a two-step assay: direct nasal assay, to memorize aromas, and the palate/after aroma analysis, to memorize taste and fragrance sensations.
To identify positive and negative characteristics conveyed by a particular flavour, the science of assay uses specific vocabulary. The term fruity identifies a flavour reminiscent of the scent and taste of fresh, healthy olive. This will range from light to intense, depending when the olive was picked.
Bitterness and pungency – a pleasing hint of prickling in the throat – is typical of top-quality oils, made from just-ripe green olives, picked and pressed within a few hours of leaving the tree. As olives ripen, these traits fade and the oils they are used to produce will be less fruity, pungent and bitter. It should be borne in mind that oil is a natural product and its characteristics will differ from year to year, or even within the same year. Moreover, oil kept in a bottle will become milder as time passes. All these factors mean that two bottles of the same oil will have different nuances of taste without this leading to loss of the sensory features.
Fruitiness, bitterness and pungency come from the polyphenols naturally present in extra-virgin olive oil, which are antioxidants that provide powerful protection for our bodies. This is another reason why they are the main sensations listed among the positive characteristics in the sensory evaluation of an extra-virgin olive oil, but there are also others.
Sweetness is the taste of an oil made with fully ripe olives, Almond is the pleasing aftertaste that recalls fresh or bitter almonds. Grassy is the nose note typical of freshly-cut grass. Floral is the nose note typical of the scent of flowers. Artichoke is a flavour that recalls a raw artichoke heart. Tomato leaf is the nose note that recalls tomato leaves.
To identify the negative traits of an oil, a number of specific descriptors are used.
Fusty is the term that describes a flavour deriving from olives that have been heaped up and have fermented; Musty is the term that describes the flavour typical of an oil made from olives left in heaps for several days in damp storage. Muddy is the flavour typical of an oil that has come into contact with the vegetation liquid generated during pressing. Winey-acetic is the flavour reminiscent of wine and vinegar, caused by fermentation of olive paste during pressing, especially in traditional oil mills. Rancid is the flavour shared by all fats in prolonged contact with the air, and which is normally accompanied by a reddish-orange tinge. Cucumber is the flavour deriving from too much time spent sealed in tins. Cooked or overcooked is the typical flavour of oil that has suffered excessive or prolonged heating during milling. Earthy indicates an oil made from fallen or muddy, unwashed olives.
Requirements for a good extra-virgin olive oil
In general, when choosing an extra-virgin olive oil, it should be remembered that an oil on sale at a very low price may reflect poor quality. An extra-virgin olive oil must meet the legal requirements defined for quality standards. Therefore, the label must always state that the bottle contains “extra-virgin olive oil”, the company name and all of the producer details. It must also show the batch number and expiry date.
A label containing information on the origin of the olive groves, olive harvesting and oil extraction processes may offer further guarantees, but this information does not necessarily declare quality indications. For this reason it is important to know how to read the label and pinpoint the parameters useful for ascertaining the quality of the oil.
Here are several of the most common indications regarding the origins of an oil:
Italian or EU oil?
Providing information about the origin of an oil does not mean assuring it is of good quality. A product produced entirely in Italy is not necessarily better than a blend of EU or non-EU oils.
It is true that in some areas of Puglia, Sicily, Umbria, or Tuscany the presence of certain native cultivars, environmental conditions and a particular microclimate results in the production of an excellent extra-virgin olive oil. In the same areas, though, if the rules for making good oils are not followed to the letter, the resulting oil may have more or less marked defects.
On average, only 30-40% of oils produced in Italy can be called good quality and free from defects. And by the same token, anywhere in the world where those procedures are followed (rational approaches, olives harvested at the optimum stage of ripening, storage of the olives in well-aired places, extraction of the oil just a few hours after harvesting using high-tech processes, proper storage of the oil in hygienic tanks at controlled temperatures), then an excellent extra-virgin olive oil will be the result.
The geographical origin of an oil is therefore not a guarantee of quality. It is no coincidence that the label “100% italiano” may be also be applied to “virgin” oils, namely those of lower quality than EVOs. Putting emphasis on the Italian nature of the oil does not offer guarantees of its quality.
Pressing and extraction processes
The term “first cold-pressed oil” is no longer indicative of an oil’s quality, as currently all extra-virgin olive oils derive from a single pressing.
Although we all imagine oil comes from first pressing, this is an anachronistic concept and refers to an era when machinery was driven by human or animal power, and needed two or three pressings to extract all the oil present in the olives.
Traditional extraction by pressing is a system with considerable disadvantages: it requires a lot more manpower, is more complex to manage from a health and hygiene prespective, and is not easily monitored with state-of-the-art technology.
Not even the expression “cold pressed/extracted” certifies EVO quality. Almost all EVOs are now made with “cold extraction” or “cold pressing systems, namely processes in which temperatures never exceed 27 °C.
Some of the objective parameters which the consumer can use to measure oil quality include acidity and sensory characteristics.
The percentage of acidity of an oil corresponds to the amount of free fatty acids present in the oil itself, and indicates the greater or lesser degradation of the olives: the lower the acidity, the longer the olives were kept in good condition.
However, the acidity of an oil is not something we can actually taste, but can only be measured by chemical analysis.
Furthermore, a generic indication like “low acidity” does not offer any kind of really useful information.
Indicating the level of acidity of an oil makes sense only if associated to analytical and sensory values.
The batch number on our labels can be read as follows:
If we should receive a complaint, the production batch code will enable us to identify the worker who bottled that particular oil, to find the quality control carried out and the materials used for and during production, and to identify exactly which oil it was.