What does the quality of olive oil depend on?
The quality of oil depends on various factors, which are all part of the entire production cycle, from the selection of olives at the correct point of ripeness, the kind of extraction process, to the storage of oil. All these factors contribute to determining the quality of the end product.
Three quality parameters can be directly checked by consumers:
An extremely low price should alarm a careful consumer
The acidity indicated on the label, which is necessary but not sufficient
The sensorial evaluation, that is to say, if there is an intense olive taste together with more or less intense bitter and spicy sensations, evidence of a fresh olive taste and the absence of defects due to excessive ripening of the olives or bad oil extraction.
In order to obtain a good oil, it is necessary to start with a high quality raw material which in our case is the olive.
It is crucial that olive groves are well organized and located in areas with a natural disposition for olive growing.
The main points can be summed up as follows:
The use of the best olive varieties, the most suitable for the particular climate of that area, for the water available and for the type of soil.
The trees must have a correct density and be pruned every year, fertilized and protected against the most common parasites of the olive tree.
Only this way it is possible to produce high quality olives.
The olive picking method considerably affects the quality of the oil produced.
In brief, these are the most common picking methods:
HAND PICKING : Olive picking directly from the tree
BROWSING: The olives are picked directly from the branches. It is the oldest method and it causes less damage to both the tree and the olives. The olives are picked either by hand or by using a sort of a comb (“pettine”) that rakes the branches (the comb can also be mechanically activated).
BEATING: the branches of the tree are beaten/shaken with a pole that makes the olives fall into nets previously placed under the olive tree. This method is up to three times more efficient than the browsing but it can damage smaller branches and the tree itself.
OLIVE PICKING FROM THE GROUND: this method is used when the olives are overripe and naturally fall on the ground. The olives are picked either by hand or with brooms. The disadvantage is that the olives at this stage are rotten and mouldy. By falling on the ground an coming in contact with the soil, olives get damaged, thus worsening the quality of oil. MECHANICAL PICKING SHAKING: the tree is firmly held by a mechanical arm: it shakes the tree making the olives fall into nets, either attached to the arm or spread on the ground. The olives are then picked up with special vacuum machines. This method guarantees a high crop, but it can be used only on plain surfaces.
It is a system of picking olives from the olive tree by shaking the branches with long poles and making the olives fall in nets previously placed under the trees. This is not a very rational system as it can cause damages to the most tender branches of the tree.
It is the moment of ripeness in which the drupe (olive) changes colour from light green to violet to completely black. Green or Black olives do not exist but simply they are all green at first and then they turn black while becoming ripe. If you happen to find green olives, it means they have been preserved in brine. The darkening index is a visual index useful to indicate the colouring phases of the varieties of olives:
0: Olives with an intense or dark green surface
1: Olives with yellow or green/yellow surface
2: Olives with a yellow surface and red spots
3: Olives with a pinkish or light violet surface
4: Olives with a black surface and completely green pulp
5: Olives with a black surface and violet pulp in half the olive
6: Olives with a black surface and violet pulp to the seed
7: Olives with a black surface and completely dark pulp
This statement does not make sense because all oils come from a first and only squeeze.
No! “Cold-pressed” or “cold-squeezed” is absolutely not an indicator of better quality of the product. Such claims only indicate one of the methods of extraction (torchio: milling by traditional pressing system) but surely not the quality. The quality is not guaranteed because if poor quality olives are “cold-pressed”, the oil obtained will be Extra Virgin but poor quality! In addition, such an extraction system does not guarantee that hygienic standards are respected since during various stages of extraction, olives are continuously exposed to air (thus favouring oxidation) and are in contact with the dry residues of previous pressing.
A Panel Test is an aroma and taste examination of the product carried out by a group of at least eight professional tasters, who memorize the type and the intensity of the good qualities and defects and register the results on a form, where all the good sensations (fruity, apple, grass, leaf, bitter and spicy) and the negative sensations (wine flavour, mould, earthy, fustiness, rancid and sludge) are listed. Conventionally, a score of 6.5 is given when no defects are reported. The Panel Test examination is compulsory for Extra Virgin olive oils (it is the only food product whose minimum chemical and sensorial characteristics are governed by Law). In any case, the Law unfortunately tolerates one point; this means Extra Virgin olive oil can have a minimum score of 5.5 and therefore, it can have defects. That is the main reason why consumers are confused. On the supermarket shelves, consumers find oils with labels indicating “Extra Virgin”, but among them, some are defective, some are acceptable, some are very good and some are real “cru”. In addition, if we consider that many consumers think of the intense taste of olive oil (bitter, spicy, etc.) as a defect, they are left with a choice of purchasing oil from a company (big or small) they trust. This sensorial method of evaluation called panel test was regularised by COI (International Oil Council) in 1987 and in 1991 was introduced by law by the EU with the above tolerance of 5.5.
No, all fats both of animal or vegetable origin give our organism the same calories equal to 9 Kcal per 1 gram Extra Virgin is better than the others because of the kind of fat it contains.
As far as its digestibility is concerned, we can confirm that Extra Virgin olive oil is absolutely the most digestible, firstly, because of the taste it gives dishes as a dressing making them more digestible and then, because of its balanced composition of saturated, monounsaturated and polyunsaturated fatty acids. In fact, compared to “all” other vegetable and animal fatty acids, olive oil has an advantage: it has a limited content of saturated fatty acids (responsible for the increase of LDL-cholesterol (the bad cholesterol) in blood with the already well-known consequences, such as the sclerosis of arteries, and possible coronary cardiopathies). Furthermore, it contains enough quantities of polyunsaturated fatty acids (the essential fatty acids for every animal organism) and high quantities of monounsaturated fatty acids, which dramatically reduce LDL-cholesterol levels, but they keep the content of HDL-cholesterol (the good cholesterol) high. In addition, the main monounsaturated fatty acid of olive oil, oleic acid, stimulates the oesophageal sphincter (the valve which prevents food from flowing back from the stomach to the oesophagus) to close properly and is beneficial in many cases of gastritis caused by the faulty closing of this valve. Oleic acid also stimulates the contraction of the gall bladder and so, it favours the release of bile (that is to say, fast digestion) and limits the formation of gallstones. Therefore, saying that Extra Virgin olive oil has a “heavy” taste is simply confirming a common stereotype because in fact tastier oil makes food more appetizing and more digestible. Furthermore, if the taste of oil is more intense, you will need a lower quantity of it, which will save you money and bring greater satisfaction to your palate.
Thanks to its content in fatty acids which are more stable than those contained in seed oils, olive oil is ideal for frying. In fact, its critical frying temperature is definitely higher than the usual frying temperature of food. The critical temperature of other fats, such as butter and margarines, is considerably lower and when frying these fats can cause the formation of acroleins and other oxidation derivatives harmful to health.
CRITICAL FRYING POINTS OF OILS AND FATS: Critical Temperature
IDEAL FRYING TEMPERATURE 180°C
LARD, COCONUT 180°C
SUNFLOWER, SOY BEAN 170°C
GRAPE SEED, COLZA AND CORN 160°C
As you can see the critical temperature of olive oil is higher than the ideal frying temperature of 180°C for perfect frying. The critical temperatures of oils extracted from coconut, sunflower, soy beans, grape seeds, colza (or mixed seed oils), lard, corn, margarine and butter are, on the contrary, lower; that’s the reason why these oils and fats are not indicated for frying.
From the above table you can see that the critical temperatures for peanut and palm oils are higher, that is why they have a better resistance. Yet, these fats are richer in saturated fatty acids and from the nutritional point of view they can block the arteries and provoke the formation of thrombi, which are the usual causes of pathologies, such as cerebral thrombosis and infarction.
Compared to olive oil, the critical temperature for Extra Virgin olive oil is slightly higher. In any case, expert cooks and clever housewives prefer to use olive oil. The reason being that Extra Virgin olive oil, because of its strong flavour adds a very intense flavour to the fried food which may cover its flavour and give it a dark colour, which is not as appreciated as the typical golden yellow colour of fried food.
It is the percentage of the free fatty acids present in an oil and indicates the level of conservation of olives used in extraction. Obviously olives in a better state of conservation will result in an oil with lower acidity. It is not possible to determine acidity of an oil by simply tasting it. It can be measured only through chemical analysis. This is why it is necessary not to confuse the intense and spicy flavour of fresh and healthy oil with high acidity.
In some areas in Italy (in Umbria, Toscana, Puglia, Sicilia, etc.), thanks to particular cultivars and to the climate, the world’s best quality oils can be produced; but, in these same areas as well as in others not as specialised in olive growing and oil production, if “The 7 Golden Rules” are not followed, defective oils will be produced.
They are antioxidants, which slow down oxidation, in the same way, if not better than vitamin E and thus prevent cell ageing. They have a slightly bitter and pungent taste, which characterizes oils of high quality, they are widely found in nature, not only in oils but also in fruit and especially in grape skins to which they give colour
It is the olive fruit, of oval shape, composed of the skin, pulp and seed.
This word defines the variety of the olive plant of the Olea Europea species. In Italy there are over 700 different kinds.
Fiscoli are the disk shaped mats on which the olive paste is spread after being crushed. They have a hole in the middle and are usually made of nylon fibre. Its weak point is the difficulty in cleaning as it is an ideal habitat for bacteria and fungus and they are usually washed only once during the entire milling cycle which, because of their very tight weave are almost impossible to wash thoroughly.