Oil is one of the most appreciated products that the land in Umbria offers.
It may compete with the best in Italy and with the fat of the ham it is almost the only condiment used. With the mark "extra virgin" (it has obtained the DOP Umbria", Protected Origin of Denomination) it has conquered the national and international markets.
A LITTLE HISTORY
In 1565 there was published the "De bonitate et vitio alimentorum
centuria", written by Castel Durante da Gualdo Tadino, botanist and doctor, chief physician to Pope Sisto V. Regarding extra virgin olive oil, Castel Durante wrote: «The oil of the olive is much boasted about and very mild, and similar to nature, as when sweet of at least two years, but not too old, as with mature olives». You may be astonished, reading these lines; above all that of «sweet of at least two years» and marvel at our palates, in the habit of appreciating a fresher taste, younger, and not to despise the bitter component, which represent an essential element. A little like wine, it is necessary to take into consideration that the history of oil is a history of taste and not less than the techniques used; above all olive oil as a food, even in the historic periods of production, was not always customary.
In Umbria, one of the first regions in Italy to practice olive-growing, introduced by the Etruscans, a strong impulse came with the Roman civilization, when many patricians developed the region as a seat for their summer holidays. In effect in one villa in Montefalco (at Mura Saracene), in Giano dell'Umbria (at Quadrellana), in Trevi at Borgo), there were found some time ago containers for oil and, in the case of Trevi, an oil mill made from sandstone. The consumption of oil, perogative of well-off families, was however tied to cosmetics, more than for use as a food. After a long period in which, it seems, the Roman market became reduced due to frequent economical crisis, there was a notable reduction also in olive-growing, the first signs of renewal are seen with the reform of the agrarian properties and with the development of centres of catholic cults, which used the oil in their liturgies. A decree obligated the farmers into planting and grafting annually, a quota of olives: the superficial olive-growth, until reaching the mazimum dimensions.
In this new season for the olives, there spread the regular work of producing home-made oil which developed in the urban centres and, above all, that of the nutritional camp. Even if, at that time, the nutritional properties of olive oil were ignored, this resulted more convenient than animal fats and easier to preserve. A food for the poor citizens, therefore, used above all in medieval Umbria, by the urban population classes.
Period of the picking of the olives.
The best period for the picking of the olives is that in which yields the maximum production of oil with the best organoleptic characteristics (taste, perfume etc.).
On the contrary to how widely spread is the belief, this state does not correspond to the phase of the advanced maturation of the olives, infact with the maturing process this only increases the yield in the oil from the olive and is only outward; caused by a progressive loss of water from the part of the pulp and is not tied to a further increase of oil.
The picking therefore must be followed at the moment in which, reaching the maximum growth of the olive and a good ineolazione, the bunch has not yet suffered a condiderable loss in the product. In the course of the maturation there is help, in particular for some cultivar those of Moraiolo, Leccino and Dolce Agogia, of a progressive coloration of the olive (darkening) that initially affects the epidermis and then spreads, with the passage of time, to the internal part of the fruit.
For those who want to point at the moment of attaining an oil of the highest organoleptic characteristics and so to the "standardization" of the product, it is recommended that the olives be picked when they have reached a partial or total superficial coloration of the fruit.
Criteria for the storage of olives.
To obtain an oil with the highest characteristics of quality it is adviseable to crush the olive within a short time (maximum 1-2 days) after being picked.
It is not always, however, possible for the oil mill to produce the oil from the olives that are delivered daily and so it is necessary to provide for storage for those days in which the olives wait for the pressing. During this wait there may happen some chemical modifications to the fruit which bring about an increase in the grade of acidity and oxidization of the oil.
These processes happen rapidly if the preservation is more than 3-5 days, in particular if the conditions of preservation are not optimum and if we speak about olives in an advanced state of maturation, or damaged, bunched or attacked by the olive fly.
The best conditions for the preservation of the olives are the following:
- Low temperature (10-15° centrigrade).
- Low humidity relative (not superior than 50-60%)
- Storing in thin layers which allows a circulation of air between the different layers.
A system of the most rational methods of storing olives is that which consists of layers of a height not more than 10-12cm.
This method may be done using the pavement or better still using rush matting or superimposable frames. With these structures brings about notable economy and a better circulation of air; as an alternative it is possible to use drawers of perforated plastic, always avoiding layers superior to 20-30cms.
The cleaning operation.
Before beginning the process of extraction it is necessary for an accurate cleaning of the olives eliminating all the foreign bodies which may spoil the oil obtained.
Manually, or thanks to automatic machines of suction, the olives are separated from the foliage residue and other impurities.
Even if the olives have had contact with the ground, there exists a procedure of washing in running water (there exist special machines) that with a forced circulation can eliminate from the fruit every residue of the earth.
If however the olives where picked by hand and stripped of leaves, and are clean, the washing is no longer necessary and this contact with water, if not indispensable, is avoided.
The extraction of the oil.
The operation of extracting the oil from the olive may be divided into three principle phases: Pressing, Kneading, Squeezing.
Frangere (to press) (from which derives the name frantoio) means, literally, to break: in this phase in fact the pulp and the nuts of the olives are torn apart through an energetic treatment by the muller (an ancient machine with stone wheels) or with the modern hammer olive press.
This operation consists of a continuous and prolonged rubbing of the paste coming from the pressing (or crushing). That favours the breaking up of the water/oil emulsion, formed during the pressing, and the union of the small drops of oil in drops becoming always larger, from these the vegetable water is easier to separate.
Even if this operation favours, in the meantime, the rising up of defects in the oil, it is considered a "necessary evil", because, only through this process, may be reached the rendering of the total extraction of 80-85% of oil.
The possibility of the rise in defects in the oil during the kneading is caused by the fact that this slow and particular mixing brings about an increase in the temperature to around 25-30° and it is an intense exchange between the oil and the water, provoking both the passage from one to the other of two components and vice versa, and the activation or the continuation of the mechanism of the hydrolytic and oxidizing alterations.
All of this goes to cut into, a more or less, marked organoleptic modification of the product (phenolic concentration, etc.) which becomes much more intense the more mature the olives.
From this we can deduce that the time and conditions of the pressing and kneading are not able to be standardized, but must, instead, be carefully valued in base of the grade of maturation and to the hygienic-sanitary state of the olives.
Once the oily must is ready, there proceeds the phase of the true extracation, which brings about the definite separation between the three components of the paste, namely the marc oil, water of vegetation and the oil.
There exist various methods to arrive at the final product, but the large lines may be lead again to two large groups, founded on the discontinuing or continuing character of the operation.
The first group is at the head of the most traditional of the systems, the extraction by mechanical pressure: the paste is placed on disks of vegetable fibres (fiscoli, which today are frequently made of synthetic materials) and the disks are stacked under the press, where the pressure grows over an arc of about one hour and squeezes out a component oily liquid (must oil). The solid part which after the squeezing remains stuck to the fiscoli is the marc oil, an element of great importance in the traditional economy of olive-growing: an excellent combustible, the marc oil still contains from 2 to 6% of material fats, which may be separated using particular solvents, using with similar procedures of those used for seed oils. The methods continue, today used widely, have substitued pressure with other principles of physics that bring about the separation of the oil from the solid part.
The extraction system used is that of centrifugation, for example, exploiting the different weights specific to the single components, brings about firstly the separation of the marc oil and the liquid part, and then following that, isolates the oily component from the vegetable water.
Another method, the filtering, makes a lever instead by the different superficial tensions that the oil has in respect to the vegetable water; in the rhythmic immersion of thin plates of stainless steel into the olive paste, there comes progressively collected, the liquid that adheres to their surfaces.
With this system there is extracted from 60 to 70% of the oil contained in the olive.
The remaining is separated from the residue of the skin and seeds by a centrifugal system, and is still through another centrifugal treatment that the residue of the vegetable water is eliminated.
Independently from the methods used, at the end of these operations, the oil is left to rest, until all the foreign substances are deposited on the bottom (settling), after which proceeds the pouring off.
Preserving and maturing.
The oil which is not sold straight away is preserved in opaque containers, away from light and excessive temperatures.
The temperature, in fact, is maintained at a constant 14-15°C. Likewise the oil must be poured off again after some months to liberate it from the dregs which during this period has been deposited on the bottom.
A new pouring off must be effected at the end of another six months, during the autumn.
The perfumes and taste of the oil.
Oil may have different aromas: the principle ones are:
- harmonious fruity: an aroma that recalls the perfume and taste of the fresh fruit justly mature that remain intact during the course of storage of the olives and to the extraction of the oil;
- strong fruity: aroma of the same type but with more pronounced characteristics;
- mature fruity: pleasant aroma a little weak, nearly sweet, of oil obtained from over-ripe fruit;
- tired or extinguished fruity: fruity aroma characteristic of very old oil.