Olive Oil : Selection, Use, Storage.
June 24, 2013 Admin 0
Selecting the best olive oil can often be problematic due to the plethora of brands, varieties, colours, bottle types and prices at even modest supermarkets and grocery stores. Although most people have come to recognise the two main types, the lighter ‘olive oil’ and the darker ‘extra virgin olive oil’, there are actually several types and manufacturing processes which effect the end product considerably from a nutritional perspective.
Extra Virgin Olive Oil, is usually produced from the pressing of fresh olive crops and is the least acidic, the most palatable and has a desirable dark green-gold colour. It is more expensive to manufacture than regular ‘olive oil’ and therefore costs more, although most multiples will retail various brands on offer regularly. The acidity of extra virgin is usually under 1%.
It is advisable to look for extra virgin olive oil that has been ‘cold pressed’. By using heat in the extraction of the oil from the olives themselves both the structural and nutritional value of the oil degrades. It also effects the taste. Typically, heat from steam or hot water was used on the second pressing of olives in a bid to extract more oil from the harvest, yielding more oil per crop.
Just like olive oil itself, cold pressing and its use can also mean several things. Pastes of olives can still be warmed to room temperature during malaxation before being centrifuged and decanted yet still be deemed ‘cold pressed’. In Europe, particularly in Spain and Italy where the majority of olive oil is manufactured, certain EU regulations deem ‘cold pressed’ if pastes are kept under 27 degrees centigrade.
Virgin Olive Oil, has a higher acidity than extra virgin, sometimes up to or around 2%. Generally speaking it is lower in overall nutritional quality than extra virgin also.
Light Olive Oil, is an olive oil that is manufactured from refined olive oil, has a similar mono-unsaturated fat content to other olive oils and is generally lower in nutritional value than the virgin olive oils.
Olive Oil, can be sourced from olives or blends of olive oil and pomace oils. Pomace is the residuals of extra virgin olive oil processing, in general it is waste product, but only in the same way certain products of cheese manufacture are considered ‘waste’ but used for other purposes.
Olive oil (and labelled as just this), is the cheapest variety to produce. It has a weaker flavour than other varieties and the highest acidity. As it is likely to be heat damaged (and so is light olive oil) it is not recommended to be consumed at all. All things being equal, extra virgin olive oil, cold pressed (some investigation of the actual pressing temperatures is a good idea) is always the first and last choice when buying and consuming these products, both from a health and quality perspective.
Storage and Use.
When using and storing olive oil, certain measures should be taken to preserve its integrity. Although the oil is robust, you can encounter several issues and these can contribute to rancidity over time. Even though it is less susceptible to rancidity because of its high unsaturated fat content, reasonably good care must be taken to store the oil and prolong its use.
When purchasing extra virgin olive oil in large quantities, like metal cans, the oil should be decanted to a glass lidded jar or a screw cap bottle and kept away from light sources. A dry, dark cupboard will usually suffice. The ideal storage temperature is around 14 degrees centigrade, so cupboards away from potential heat sources like sunny windows or ovens is required. Storing the oil in a refrigerator is not recommended as it may lead to clouding. If the oil has to be stored in a fridge because the room temperature is too high, letting the oil sit out of the fridge for a while, before use, will allow it to return to its normal consistency.
Further reading on Olive Oils can be found within this article.
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