Pressing matters | Olive oil
Olive oil is part of the Mediterranean diet and features on nearly everyone’s shopping list… but what kind of olive oil to buy? Virgin, extra virgin, pomace, filtered, cold pressed, stone milled… the list goes on. One thing is for sure though: not all olive oils were created equal.
Rachel Zammit Cutajar
Virgin olive oil is obtained from the olive only, in conditions which do not alter the oil in any way. It is pure fruit juice, so to speak. It also meets a set of chemical standards. Extra virgin is the best of these, pressing with perfect flavour, aroma and minimum acidity.
Refined olive oil is obtained by treating low quality or defective virgin olive oil with the use of charcoal and other chemical and physical filters.
The term 'olive oil', when used alone, refers to a blend of refined olive oil and virgin olive oil.
Pomace is the ground flesh and pits left after the extraction process. Olive-pomace oils are obtained by treating it with solvents or other physical treatments.
Cold-pressed oils are pressed maintaining a temperature of 27°C or colder, after which the chemical components of the oil begin to alter. Heating olive oil beyond this temperature will compromise the flavour and aroma or the oil. Therefore, it is advisable to use expensive premium olive oils on salads or drizzled over pasta, or with a chunk of Maltese bread, rather than for cooking.
Olive oil is best at its freshest, as light and oxygen begin the deterioration process of the oil. Therefore it is best to purchase an olive oil with a harvest date, or an expiry date and store the oil in a dark air-tight container.
During the Roman rule in Malta, one of the main characteristics of the Maltese landscape was large villas that included a vast number of olive groves on their land which were used for the production of olive oil. During the British reign however, many of these olive trees were removed to make way for barracks or other herbs.
The poor quality alkaline soil found on Maltese hillsides reduces the acidity found in the olives, making for excellent olive oils.
Today, olive oil production on the island is experiencing a rebirth, with a handful of Maltese companies producing premium olive oils using the remaining local olives and more and more olive trees being planted on the island.
Infusing olive oils at home with herbs and other ingredients will intensify the flavour of olive oils. However there are safe and unsafe ways of doing it.
Anything which contains any trace of water or moisture – including garlic, lemon peel, fresh peppers, fresh herbs and spices – will support the bacterial growth, and is thus unsafe, even if in a sealed bottle. To avoid botulism bacteria, refrigerate infused olive oil and use within a week. Alternatively, ingredients can be dried before infusing in olive oil. This can be done in a food dehydrator, or simply left to dry in the sun. The safest way to flavour olive oil is to add ingredients to the olives during the pressing stage, however you have to have your own olive press to use this method.
