Taste
Taste is responsible for detecting four basic sensations: salty, sweet, sour, and bitter. This sense is made possible by taste buds—specialized structures located in the mucous membrane throughout the oral cavity, particularly concentrated on the tongue's papillae.
There are four types of lingual papillae: fungiform, filiform, circumvallate, and foliate. These vary in both their sensory function and the number of taste buds they contain. The receptors for the four basic tastes are not uniformly distributed across the tongue; instead, certain regions are more sensitive to specific flavours.
The tip of the tongue, which is rich in fungiform papillae, is particularly responsive to sweet tastes. The edges of the tongue, where filiform papillae are most prominent, primarily detect salty stimuli. Just behind these, foliate papillae are especially sensitive to sour flavours. Meanwhile, the back of the tongue, where circumvallate papillae are located, responds most strongly to bitter substances.

Smell
When a bad cold blocks our nose, we often struggle to recognize the taste of the food we’re eating—highlighting just how essential our sense of smell is in flavour perception. Olfactory cells, located in the upper part of the nasal cavity, are the key elements of this sense. By responding to the chemical signals of aromatic substances, they detect and categorize molecules with specific sensory characteristics.

Sight
The mere sight of food can trigger a range of involuntary responses - think of the sudden onset of hunger or, more precisely, appetite. When we can’t see what we’re eating, it can create a sense of unease or mistrust: try putting food in your mouth with your eyes closed or covered—you’ll probably hesitate. Colour is arguably the most important visible trait of food and can have a powerful psychological impact.

In the context of oil tasting, opinions differ on the importance of visual evaluation. Experienced tasters know that appearance isn’t the most critical factor, but it can still offer useful clues about an oil’s quality. For example, swirling the oil in a bottle can reveal insights into its clarity and roundness. A sample that leans toward an orange hue may indicate early stages of oxidation. For those without tasting experience, it’s generally recommended to taste the oil without looking at its colour.

The colour of olive oil is determined by a variety of fat‑soluble pigments - xanthophylls, chlorophylls, carotenes, and carotenoids. When chlorophyll predominates, the oil appears green; in contrast, a higher concentration of carotenes and carotenoids produces oils with shades ranging from pale to deep yellow. The aromatic nuances detected through smell and taste stem from numerous compounds, including alcohols, aldehydes, esters, hydrocarbons, and polyphenols.
These substances originate from specific compounds naturally found in olives that, through hydrolytic processes, become partially soluble in the oil. In many freshly pressed oils, bitter and pungent notes are predominant, often accompanied by a mouth-coating sensation - qualities largely attributed to the oil’s high content of flavonoids and secoiridoids.