Acidity is one of the parameters that measure the quality of olive oil, but it also depends on the variety of the olive and the place of origin. For this reason, it cannot base the quality of the oil solely on acidity. Prestigious brands are using acidity as a classification parameter for olive oils, actually confusing the consumer.
The quality parameters of olive oil are year of production, organoleptic score, level of peroxides, acidity, k-232, k-270, etc. In our shop in Las Rozas de Madrid or online shop we offer you all this information, such as the origin of the oils and their varieties: Baena, Sierra Magina, etc.
Fatty acids can appear in oils or in their molecular form as free or as radicals that make up triglycerides. The acidity of the oil, or degree of acidity, refers exclusively to the percentage amount of free acids in a sample.
The index or degree of acidity is defined as “the amount by weight of free acids in 100 grams of oil”. However, it is agreed that the index or degree of acidity, given the majority proportion of oleic acid, is defined, for olive oil in practice, as follows: “the amount by weight of free oleic acid in 100 grams of oil”.
Therefore, when we say that the degree of acidity of an oil is 0.4, it means that in 100 g of oil there is 0.4 g of free oleic acid.
Olive oil 0.4 Information or deception?
There are therefore oils with different degrees of acidity, this index being generally, together with others, a measure of the quality of the oil, but it has nothing to do with the flavour of the olive oil, as these components do not give the olive oil any flavour, colour or smell.
Hydrolysis is responsible for the elevation of the degree of acidity in the oils. Therefore, in general, the higher the degree of acidity of an oil, the more deteriorated it is. However, it is necessary to take this data with caution because there are quality oils with high indexes, because the acidity is also determined by the variety and climatological factors of the place of origin.
In order for hydrolysis to take place, the presence of water and an increase in temperature are necessary. Thus, there are two factors that favour the hydrolytic process: heat and humidity, which are responsible for the high degree of acidity of an oil.
The deficient milling with excessive time of beaten and the elevation of the temperature that it entails, or the elevation of temperature itself on the part of the manufacturer in its desire to extract more extra virgin olive oil and the presence of water coming from the excessive washing of the fruit previously, are determining factors for the control of the acidity. A good milling is fundamental to obtain a quality oil.
The hydrolysis process is also favoured by the presence of enzymatic catalysts coming from microorganisms, in contaminated oils, in particular the presence in the fruits of the parasite “Dacus oleae” or “olive fly”, endemic in many areas, produces increases in acidity. The fruit to be ground must be free of parasites.
Hydrolysis is also encouraged by the prolonged atrophy of the olive, which encourages the appearance of various parasites in the fruit, especially in very ripe olives, by the presence of damaged fruit and largely by the lack of cleanliness and hygiene of the facilities of the mill.
In any case, low acidity guarantees good quality extra virgin olive oil. In the rest of the refined oils it is not indicative of quality, since this is lowered by means of chemical processes.
Photo: Olive oil analysis
Acidity of sunflower oil and other refined oils
The oil of sunflower, peanut, corn is obtained by means of processes of chemical extraction and high temperatures, using authorized solvent. That they are authorized has nothing to do with being healthy, since hexane is used, which is very poisonous, although it is then subjected to high temperatures for its complete elimination.
It should be borne in mind, unlike virgin olive oil, that the seeds can not be obtained oil only by physical procedures, squeezed, because of the seed, despite how much squeezing, no drop of oil comes out.
Subsequently, in order to correct defects of these chemical processes may have created the extraction, it undergoes a refining process. During the refining process, phospholipids, metals and free fatty acids are eliminated, the latter being the ones that give the acidity to the oil. Likewise, during extraction the oil can take on darker colours, so that it could also undergo a deodorisation process, finally obtaining a lighter and more uniform oil.
Can our palate detect acidity?
Known oil brands have set the acidity of the oil as a differential value. The acidity of the oil can only be detected by a laboratory and has nothing to do with taste. It is true that acidity is a sample of quality, but in the case of all refined oils, it is a chemical variable that can be adjusted to the values one wants.
the best option is to stop consuming refined oils, which are all from seeds and use for every culinary dish a good extra virgin olive oil. If the extra virgin olive oil of the most common varieties, picual, cornicabra or other softer, such as hojiblanca seem somewhat strong and flavored, you should go to the varieties of extra virgin soft, arbequina and empeltre.
An extra virgin olive oil contains all the benefits of the fruit from which its oil comes, the olive. Refined oils have undergone complex processes where most of their beneficial components have been left by the wayside.