Mouthfeel is paramount in the assessment of wine quality. It is one of the last aspects perceived during the wine tasting process and can mean the difference between a good wine and a great wine. Wine mouthfeel is mostly a tactile sensation. Mouthfeel is made up of several distinct factors: fullness, smoothness or roughness, particularity, oral dynamics, irritation or heat, mouthcoating, dryness, and length. In the case of particularity, wine is evaluated for the sensation of particles being present e.g. the sensation of talc vs. chalk. Oral dynamics is a very interesting concept which describes how your lips and cheeks move on account of the astringency of the wine. Do your cheeks pucker or is there as sensation of adhesiveness between your lips and gums?
Astringency in wine
Astringency, which is a combination of the mouthfeel factors defined previously, is an important part of the mouthfeel perception in red wine. The common theory for the perception of astringency in wine is that the tannins in wine bind with the protein compounds in saliva. This causes the saliva to precipitate and leaves our oral tissues unlubricated, thereby causing the rough sensation. However, scientists agree that this is by no means the only way in which astringency is perceived. The exact combination of chemosensory, somatosensory, and mechanoreception in the perception of astringency in wine mouthfeel is yet to be scientifically pinpointed. The perception of astringency also differs from person to person. Number of taste buds, speed of salivary flow, and age all impact on the perception of astringency. The type of acids in white wine e.g. tartaric acid or malic acid also affects the extent to which tannins bind with salivary proteins thereby impacting on the perception of dryness and astringency.
The perception of body
Perceived viscosity or body in wine is largely influenced by the physical viscosity of the liquid. However, pH also influences the perception of viscosity, especially in white wines. This is partly due to a structural change that occur in polysaccharides at high pH which increases the perceived viscosity of the wine. Polysaccharides occur in white wine due to the breakdown of yeast cells toward the end of fermentation or during extended yeast lees contact. Wines made in this style often have more body.
Sweetness due to sugar content or even glycerol content also modulates the perception of body in wine where wines that are sweeter has more body. Glycerol, which occurs abundantly in white wine, is naturally very viscous and one would think that increased levels of glycerol would impact on the viscosity of wine. However, any perceived effect is likely due to the perceived sweetness of glycerol and not its physical viscosity.
The effect of alcohol content on wine mouthfeel
Alcohol content is a big contributor to mouthfeel sensations, impacting on the perception of heat, dryness, and body. There are many theories as to how ethanol affects astringency. Some scientists have found that increased ethanol prevents the de-lubrication effect of tannins while others suggest that it does not affect the total perception of astringency but rather modulates the qualitative perception e.g. velvety as opposed to grippy and coarse.
Which is better?
A wine with intense mouthfeel is often described as big. Is a big wine better? That depends. Often in wine shows, bigger wines perform better than leaner wines. This is partly because wines with less intense mouthfeel can appear insipid when they are tasted directly after a big wine. Many wine critics also have a penchant for big wines nowadays. However, when it comes to drinking wine in social settings, a less intense wine is easier to drink leading to increased volumes sold. It really depends on what the winemaker is aiming for i.e. a show wine or a scale wine. There is certainly room for both. Of course, wines from some varietals, especially Cabernet Sauvignon and Chardonnay, are expected to be big whereas other varietals such as Pinot Noir are expected to be more delicate.
Evaluating mouthfeel in wine
Your wine tasting technique will affect how you perceive mouthfeel. A small sip will not allow you to perceive all the mouthfeel sensations, while keeping the wine in your mouth for too long will cause sensory overload. There is no golden recipe for evaluating wine mouthfeel, but there are a few guidelines that you can follow. The important thing is that you taste all the wines in your flight in the same way. If you’re going to swirl vigorously, you must apply the same technique to all the wines. It is also worth it to allow enough tme between wines to ensure that most of the astringent perceptions have disappeared. It is better to take more than one sip when tasting. With the first sip, focus on the palate weight, smoothness, particularity, and mouthcoating effects. With the second sip, you can focus on heat, oral dynamics, dryness and length.