The feel of wine: what exactly is it?

If, during a tasting, someone mentions the feel of wine, don’t get the wrong idea: you’re not meant to dip your fingers into your glass to judge its roughness by hand. We’re talking about how wine feels in the mouth. In fact, the mouth contains almost a quarter of the human body’s touch receptors (yes, really!), and they allow us to feel and appreciate the texture of the food we eat and the drinks we enjoy.

The same goes for wine tasting: a wine’s mouthfeel is about more than its flavours and aromas; it has a whole tactile dimension too. Let us guide you through this often underestimated yet vital part of tasting.

Let your tongue do the talking

As well as the familiar taste buds that detect sweetness, saltiness, acidity, bitterness and umami, the tongue has touch receptors. Concentrated mainly towards its tip, these receptors help us perceive the geometry — that is, the shape — of foods and drinks, along with their texture and consistency. There are five types of receptor, each responding to different stimuli according to its function. They are generally activated by moving the tongue: unlike taste, touch is an active sense.

That’s why it’s important to move your tongue when tasting wine: to appreciate all its tactile qualities, not just its aromas and flavours. The curious wine lover can then mindfully explore the tactile qualities of what’s in their bottle (or, better still, their vial).

Surface textures: vibration receptors

First, focus on the wine’s surface by pressing your tongue against the roof of your mouth and letting just a little liquid pass through to assess how it feels: is it smooth or rough? What material does it evoke to the touch: silk, velvet, canvas? Does it leave a sensation of dryness?

Some receptors identify a wine’s texture through the amplitude and frequency of the vibrations generated when the liquid touches the tongue. For example, we might call a wine silky if it feels soft on the tongue, its tannins seeming to glide smoothly over the mucous membranes, like the fine weave of silk with its minimal friction. Conversely, we call a wine rough if its tannins seem to rub against the mouth as though their surface were grainy: this is the sensation of harshness, generally associated with young, immature tannins.

Structure and consistency: pressure receptors

Next, lower your tongue into the middle of your mouth to move the wine around and appreciate its weight, density and fluidity. Now the aim is no longer to assess its surface but its depth: how is it structured? What does its consistency remind me of, or bring to mind?

The tongue is a muscle, so put it to work: by applying pressure, these receptors help us sense a wine’s consistency. We can thus assess its viscosity: a sweet white will be thicker and more viscous than a dry white. Likewise, some red wines feel thick in the mouth, denser or even heavier. These are the receptors that convey those sensations to us.

Geometry and shape

Talking about the geometry of wine may seem a little absurd, given that a liquid takes the shape of its container, but we’re about to do just that. Some prefer the term ‘shape’, which better describes how wine settles in the mouth. What we’re really assessing is how the liquid spreads out or draws together, largely depending on how it reacts with saliva.

Some even talk about horizontal or vertical wines (what on earth does that mean?). It is, of course, a metaphor: a horizontal wine coats the whole mouth, while a vertical wine reacts with saliva in such a way that a cushion of spit forms around the sides of the mouth. The wine is then concentrated in the centre of the tongue, making it “vertical”.

Of course, many geometric terms are really metaphors. A classically ‘round’ wine isn’t actually round, as we can surely agree; it’s a wine that feels pleasant in the mouth, with low acidity and little tannin. We talk about roundness because it evokes the satisfaction of a wine that fits and coats the mouth perfectly without making the receptors contract… But hang on, is that the perfect segue?

Astringency: deformation receptors

When they come into contact with certain substances, the mucous membranes tend to contract or expand, and the sensation of contraction is particularly noticeable. Some people enjoy it; others hate it. These are the tactile effects of acidity or bitterness, for example, which act on receptors for both taste and touch. This effect is known as astringency, a well-known property of tannins, which cause the mucous membranes to tighten considerably.

Astringency, then, has little to do with taste and much more to do with touch. To assess the tannins in a red wine, it’s important to hold it in your mouth for a while: their effect only emerges several seconds after contact with the mucous membranes. Why? Because tannins’ astringent effect results from their binding to certain proteins in saliva. So both time and the amount of saliva produced greatly influence how different people taste and appreciate a wine. If you produce plenty of saliva, you’ll perceive a wine’s tannic subtleties much more clearly than someone with an unfortunate case of dry mouth.

Ageing matters too: over the years, oxidation causes tannins to depolymerise, so they bind less readily. In short, after too much exposure to air, they simply lose some of the arms they use to grab the saliva proteins making eyes at them (not for scientific purposes). They then seem more pleasant and rounder in the mouth. In fact, they lose some of their astringency and gain subtlety.

Warmth and tingling

Thermal receptors

The temperature of wine is, of course, perceived by the taste buds, which is why different wines have different ideal serving temperatures. But beyond actual temperature, these receptors also detect an illusion of heat: notably the warming sensation caused by ethanol (particularly in spirits) or very spicy wines. The opposite can happen too: menthol and eucalyptol, for example, create a sensation of coolness in the mouth.

Irritation receptors

Sometimes wine has a prickling quality: another tactile sensation familiar to chilli lovers. Spicy wines or chilli-infused spirits (such as chilli-infused rum) can irritate the mucous membranes in this way. But it’s not just about jalapeños: carbon dioxide also activates these receptors (albeit more mildly), and you may feel this irritation when tasting sparkling wines.

Follow this way for the complete guide to the stages of wine tasting!