"This oil is too acidic!" — how many times have you heard this phrase when tasting a very peppery olive oil? It's a common misconception: the acidity of extra virgin olive oil is not perceptible by taste. It's a chemical parameter, not a sensory one. Here's what it really indicates.
Acidity: what we're actually talking about
The free acidity of oil is measured in the laboratory. It indicates the percentage of free fatty acids (expressed as oleic acid) present in the oil.
Practical meaning: the free fatty acids indicate that the triglycerides (the form in which fats are "packaged" in the olive) have split. This happens when:
- The olives were damaged on the tree or during harvesting
- They were poorly stored before milling (piled up, fermented)
- Too much time passed between harvesting and pressing
- The olives had insect attacks or other pests
Acidity measures the quality of the olives and the process, not the taste of the oil.
Why acidity isn't perceptible
A surprising truth: the human body cannot perceive the acidity of oil using its senses, regardless of its value.
When you feel an oil "tingling" in your throat or having a "strong bitter aftertaste", you're perceiving the polyphenols, not the acidity. These are different things:
- Acidity = chemical parameter (free fatty acids). Indicates storage condition. Has no perceptible taste.
- Pungency and bitterness = sensations from polyphenols (oleocanthal, oleuropein). Indicate freshness and antioxidant richness.
Legal parameters
According to EU Regulation 2568/91, to be extra virgin oil must have:
- Free acidity ≤ 0.8%
But these are minimum legal standards. A good artisanal extra virgin oil typically has:
- Acidity between 0.15% and 0.30% — sign of healthy olives, harvested at the right time, processed quickly
- Our single-varietal oils range between 0.18% and 0.28% depending on the vintage
Polyphenols: the real "taste of quality"
Polyphenols are the compounds that give extra virgin olive oil its intense flavors and nutritional properties.
- Oleocanthal: responsible for the throat tingle. Has anti-inflammatory effects similar to ibuprofen (in small doses).
- Oleuropein: characteristic bitterness. Strong antioxidant.
- Tyrosol, hydroxytyrosol: cardiovascular protection
In the EU Regulation 432/2012, the EFSA recognized that olive oil polyphenols contribute to protecting blood lipids from oxidative stress. To display the claim on the label, at least 5 mg of hydroxytyrosol and derivatives per 20 g of oil (i.e., 250 mg/kg) and a daily intake of 20 g are required. A good Ortice exceeds this threshold for HT and derivatives.
How to recognize fresh oil
When tasting extra virgin olive oil, what you're really looking for is:
- Fruity: aroma of fresh olives, olive leaf, cut grass, almond, artichoke
- Bitter: present, sign of polyphenols
- Pungent: the "cough" in the throat, sign of freshness
- Clean: no rancid, moldy, or reheated sensations
The balance between fruity, bitter, and pungent defines the category ("light, medium, intense fruitiness"). None is better: it depends on use and taste.
FAQs
Is oil with low acidity better?
Low acidity (under 0.3%) indicates well-made oil from healthy olives processed quickly. But it's not enough: a good sensory profile (Md=0, Mf>0) is also needed. Low acidity + sensory defects = mediocre oil.
Why does my oil "tingle" so much?
The tingle is caused by polyphenols (especially oleocanthal). It's a sign of freshness and antioxidant richness, not high acidity. It tends to decrease over months.
What does "median of defects = 0" mean?
This is the result of tasting by certified panels. The median of detected defects must be zero for the oil to be extra virgin: no defects like rancid, moldy, reheated, or "morchia" (fermented) notes.
How is oil acidity measured?
With a laboratory titration: the oil reacts with a basic solution (potassium hydroxide) to neutralize free acids. The percentage of acidity is calculated from the amount of base used.
Can I trust the values on the label?
The values on the label are declared by the producer and must align with legal analyses. Reputable producers declare these values and accept random checks by authorities.