What is Dryness?
The tactile mechanism behind dry sensations
In previous posts, we looked at how the tongue perceives the basic tastes and how the nose identifies aromas. This leads naturally to another question: how do we perceive dryness?
Dryness is not a basic taste. It does not come from taste buds or olfactory receptors. Instead, it is a tactile sensation that emerges from how certain chemical compounds interact with the mouth.
The Astringency Mechanism
In wine, dryness is closely linked to tannins. These compounds, found in grape skin, seeds and stems, bind to proteins in saliva. When this happens, saliva becomes less effective at lubricating the mouth. This results in an astringent, drying, slightly rough sensation on the tongue and cheeks.
Tannins however, are not the only contributors. Alkaloids and Polyphenols can produce similar effects.
Caffeine can create a noticeable drying, puckering sensation. Polyphenols in fruits such as quinces, persimmons, and green bananas can also trigger a dry, chalky mouthfeel.
These compounds act on the mouth mucous membranes in a way comparable to tannins, reducing smoothness and lubrication and contributing to the sensation of dryness.
Spirits such as Whiskey also show dryness. During ageing, the liquid extract tannins and phenolic compounds from the wood. These contributes bitterness, structure, and a drying finish, influencing both flavour and mouthfeel.
How does it work?
Dryness works by changing the friction inside the mouth. When these compounds bind to salivary proteins, they reduce the natural lubrication on oral surfaces; with less lubrication, the tongue and cheeks move against each other with slightly more resistance. This increased friction sharpens the sensory input coming from both taste receptors and mechanoreceptors (the touch receptors in the mouth). It becomes easier for the brain to detect small shifts in acidity, bitterness, or aromatic lift, because the mouth is no longer coated in a smooth film.
When dryness is balance, this increase in friction makes tastes feels clearer and more defined. If the effect becomes too strong, friction rises too far, saliva is stripped away, and both taste and aroma becomes less detectable. In short, Dryness improves perception only within this narrow controlled range.
Dryness highlights the complexity of flavour perception. It reminds us that flavour is not just aroma and taste; texture and tactile sensations are part of the experience.
In a separate post, I will explore how to work with dryness deliberately when creating drinks.