I do not know if you have noticed the detail but for a while now the vinegars that we acquired or that are placed at our disposal in a hospitality service include the data of their acidity (or should do it, because it is an element of obligatory mention) .
Often, given that this product is usually combined in its use with that of oil (which sometimes also offers a data referring to its acidity) it usually generates some confusion since one acidity (that of vinegar) and another (for example that of an oil) have little to do with it. And its measurement is also done differently.
Acidity in the vinegar
In Royal Decree 661/2012, referring to the quality standard for the production and marketing of vinegars, it is stated that the acidity or degree of acidity of a vinegar is expressed as the grams of acetic acid contained in 100 mL of said product . The data may be accompanied by the symbol “grade” (º) in superscript or in the form of a percentage (%) and as stated in article 11 of this RD it is a mandatory information.
Acidity in food
In general, it is necessary to consider that in food, whatever its nature or origin, the degree of acidity indicates its content in all the free acids of the food and is expressed on the basis of the most characteristic or most of them, data that only Sometimes it has a direct relationship with the known pH or hydrogen potential. This value, that of the pH is only applicable to aqueous solutions. Thus, in the case of vinegar its degree or percentage of acidity (I have already said that it is the same) it will have a direct relationship with its pH, but not in an oil since it is an oily solution. To understand the concept of pH in food in a few words I suggest you follow this link .
To make this fact more understandable, it may be useful to know that in other foods , unlike vinegar, that acidity (not pH) will be expressed based on the acids of each food . For example: the acidity of a juice is usually expressed by virtue of its citric acid content; the one of the milk by the one of lactic acid, et cetera. And in the oils …
Acidity in oils
In the case of oil (regardless of its origin) its acidity will be defined by the amount and proportion of free fatty acids in unit volume . These free fatty acids come from the hydrolysis of glycerides. The percentage of free fatty acids (and therefore of acidity) in oils is usually calculated in relation to the fatty acid with the highest content of that oil , the most typical being oleic acid. However, in certain oils such as coconut, palm (and others) it is expressed on the basis of lauric and palmitic acid respectively.
However, unlike what the vinegar standard says , in the case of oils the mention of acidity is not obligatory in its labeling. Moreover, the inclusion of this information in the case of oils is discouraged by the European Union to the extent that the following is said in Commission Regulation (EC) 1019/2002 on the rules for marketing olive oil. :
The acidity, mentioned in an isolated way, makes us think falsely of an absolute quality scale that is deceptive for the consumer , since this criterion only corresponds to a qualitative value within the set of other characteristics of the olive oil in question. [consideration nº9]
So among the data that optionally , never mandatory, have to appear on the labeling of olive oil is that of acidity … but with a clear consideration: this data may be included as long as it is accompanied by others , now , of obligatory form. That is to say, the degree of acidity is yes, but if it is mentioned, others such as the peroxide index, the wax content and the absorbance in the ultraviolet will have to be included. This is mentioned in Article 5 regarding the optional information present in the labeling of olive oil:
The indication of the acidity or the maximum acidity may only appear if it is accompanied by the indication, in characters of the same size appearing in the same visual field, of the peroxide value, the wax content and the absorbance in the ultraviolet, determined in accordance with Regulation (EEC) No 2568/91
A circumstance that I have rarely seen fulfilled according to this norm . In the few cases of olive oils that still contribute today the data on acidity offer, in most cases in isolation … I am convinced, sadly, that this type of maneuvers respond to the interests of who do so trying to take advantage of the general lack of knowledge about this fact and the unfounded popular legend that gave greater acidity in the higher acidity to a greater intensity in the flavor and to those with lower acidity a greater “softness” organoleptic. A myth that still exists today and that seems difficult to eradicate.
Although it is true that the physico-chemical qualities of an olive oil determines to a certain extent its organoleptic qualities , especially its profile of fatty acids (oleic, linoleic, etc.) and volatile compounds (esters, aldehydes, ketones, alcohols, etc.) .); and that from the transformation processes of these lipids (lipolysis and lipooxidation), free fatty acids and peroxides are formed (increasing the acidity and the peroxide value, respectively) with which the organoleptic properties will be modified , including those affect their “intensity”. Although it is true, as I say, that “intensity” depends on multiple variables , many of them associated with the variety of the olive, degree of maturation, and so on. That is, although the organoleptic qualities especially those related to the intensity of flavor and aroma depend on several factors and being the acidity one of them, this is not or is usually the unique element and defining element to endow it with that intensity. Without going any further, we have that most of the Extra Virgin Olive Oils (AOVE) that are awarded annually as the best EVOO of the year (and many of them provide an “intensity” that pulls back) tend to have an acidity 0.2 … and even 0.1; always, of course, according to the norm, below 0.8.
On the controversies in this regard, I suggest you visit this link where it is wonderfully explained why and why not the issue of the presence of the acidity data in an EVOO or in a “normal” olive oil.