When you enter a grocery, shopping for cooking oil, what drives your decision to buy a particular type of oil? Let's assume for a moment that you already know about the nutritional value of olive oil and you've even dipped a fair amount of bread into the golden-colored liquid at your favorite Italian restaurant, so you head directly to that section of the 'cooking oil' aisle that houses row upon row of oils made from the fruit of the olive tree. There they are, clear bottles, green bottles, bottles with labels that promise 'First Cold Press' or 'Extra Virgin' or, wait a minute, there's one that says 'Single Varietal' and yet another with a picture of a beautiful Italian Estate, that one MUST be the best oil in this store! Then, happy that you've perused the labels until you found an oil that will taste absolutely wonderful with that fresh baguette you have jammed under your arm, you slide the bottle off the shelf and stride confidently to the cash register. Sound familiar? Yeah, that's what we used to do, too, that is until we started traveling to the country touted as the greatest producer of olive oil in the world - Italy. In Italy, olive oil is taken for granted, to say the least. Olives and the oil produced from the lucious, crunchy fruits, are simply part of life. Nearly every dish cooked in Italy begins with an ample amount of olive oil. Why olives? Where do they come from and how is this finest of cooking oils extracted from the fruit of this craggy tree?First, a little history . . .
The olive tree belongs to the Oleaceae family and has a life span of around 300-400 years. The precise origins of the olive tree are shrouded in mystery, Persia, Jordan, the Valleys of the Nile each have their advocates. The best that we can say with certainty is that cultivation began a very long time ago, somewhere in the Near East and spread slowly westward to Spain. All major civilisations of the Mediterranean have played a part in the dissemination of the olive throughout this region: Egyptians, Phoenicians, Greeks, and Romans.CULTIVATION OF OLIVES - HARVESTING AND PROCESSING
For the olive oil to travel from the tree to your table, it must first pass through an extensive process, always labor intensive, and only after being properly cultivated. Of utmost importance are such things as, the correct choice of trees, method and time of planting, watering, fertilization, harvesting and transport, then the actual crushing, extraction of the oil and finally storage.The olive has to undergo various procedures in order to become oil. However the immediate picking of the olives, the cleanliness during the gathering process, as well as the shortest possible time from collection to the oil-press and the crushing process, will offer the best results. In general, it has been proven that a delay in the crushing of the picked fruit will negatively affect the quality, acidity and aroma of the oil.
THE FRUIT
Olives are the fruits of the olive tree which is indigenous to the Mediterranean countries but also cultivated nowadays in other parts of the world, including Australia and North America. There are many different kinds of olives. Some are used for making oil, while others are for eating (these are usually larger in size). There are also some varieties which are used for both oil and consumption.The olive tree blossoms in spring and, shortly afterward, the olive fruit starts to grow. Bright green from the outset, the fruit has a fleshy skin and gradually ripens, becoming fully mature towards the end of autumn.Olive oil is the natural juice of this fruit, a pure product, obtained through either the use of modern machinery or by other, more natural means. The oil of the olive is found in the fleshy part of the fruit. Olives reach their maximum oil content when they are fully ripe, but the finest oil is obtained from olives that are just beginning to ripen.
In Spain, for instance, there are over 260 types of olives, the main varieties being:
Arbequina: Mainly found in the Catalonian region, it is recognized for its aromatic fruitiness, low bitterness, pungency and stability.
Cornicabra: Found in the La Mancha region of Central Spain, is very fruity and aromatic with medium bitterness, pungency and stability.
Picual : Mostly found in the Jaen region of Southern Spain and, when harvested early, produces a pleasantly aromatic, fruity oil that has medium bitterness and very high stability due to its high percentage of oleic acid.
Manzanilla: Found in the Caceres region of Southwestern Spain is fruity, aromatic and herbaceous, has medium bitterness and stability, and is strongly pungent.
Hojiblanca: Mainly found in Malaga and Cordoba in Southern Spain is fruity, aromatic, mildly pungent, is slightly bitter with low stability.
THE OIL EXTRACTION PROCESS:
1.Harvesting: The process of collecting the fruit from the trees begins in autumn; black olives are usually harvested from November to February while green olives are harvested earlier. Olives can be picked by hand or beaten from the tree (usually with flexible poles so that the olives fall onto canvases placed at the bottom of the tree), they can also be harvested using mechanical tree shaking methods.
2. Transportation: Following collection, the fruit is placed into bags, baskets or trucks in bulk form and then transported to be pressed. The olives must be handled carefully, as damage or lack of ventilation may cause fermentation. Upon arrival at the mill, the olives are washed and separated from their twigs. It is critical that the olives be processed within 24 hours of harvest, if quality olive oil is going to be produced.
3. Crushing: This process breaks the skin of the olive, cracks the pit and mashes the pulp.
4. Pressing: In order to extract the liquid from the mass of pulp it must be pressed. There are two types of oil presses:
- The classical or traditional type, maintained through the centuries, where the ground paste is placed between "capachos", special round mats and then pressed to squeeze out the oily liquid. This liquid is made up of vegetable water from the olive itself and oil.
- Separation by Centrifuge: The paste is made more liquid by adding 1 litre of water per kilogram of paste. A centrifugal decanter spins the olive paste in a horizontal drum with the heavier flesh and pit going to the outside and the water and oil being tapped off at the center.
The oil we have from the oil presses at this stage is natural olive oil. There is still some oil in the residue that has accumulated in the oil-presses. These stacks of residue are called oil-cake and contain some oil, depending on the efficiency of the oil presses, and is called seed-oil.
5. Storage: Olive oil is very light sensitive and will oxidize when exposed to sunlight, roomlight, etc. For this reason, olive oil is best when stored in dark, glass bottles. It can be stored in clear glass, as long as it is kept in a dark place. Ideal storage temperature is 10-15 degrees Celsius, or 50-59 degrees Fahrenheit.CHARACTERISTICS OF OLIVE OIL:
COLOR.
Color does not always prove the quality of an oil. The color of a good oil can range from green to golden yellow. As color is not a sure sign of quality, experts test olive oil in dark glasses. The color of the oil actually depends upon the fruit's chemistry. For instance, if the fruit contains a high level of chlorophyll, then the oil will be greener, but if carotene is predominant, then the oil will be more golden yellow. In addition, olives gathered at the beginning of the harvest usually produce oil of a greener color, while oil produced from ripe olives tends to be more golden yellow due to the increased amount of carotene they contain.
TASTE AND SMELL.
Olive oils typically possess flavors or odors reminiscent of fruits or nuts or may have a freshly pressed taste, all generally desirable. Expert testers try to pinpoint these qualities and typically use them to describe the oil. A bitter or slightly bitter taste means the olives used where not ripe when picked. A pleasant smell and taste can also be attributed to the area in which the olives grew and the way they were cultivated.
ACIDITY.
The degree of acidity in olive oil indicates the oleic acid content. Methods of harvesting, storage and pressing can affect the level of acidity. The degree of acidity greatly affects the taste. Olive Oil with a higher level of acidity will have a pungent, spicy, unpleasant taste. The highest quality oils will possess an acid content of 2% or less.
OXIDATION.
Oxidization readily causes olive oil to spoil (become rancid). Conditions during storage, such as presence of light, oxygen in the atmosphere, etc. all speed up the oxidation process. An expert tester will quickly detect this problem with a simple taste test.