Wine tasting: Sight, Smell, Taste
The first sense used to examine wine is sight. There are three kinds of color receptor cells in the eye and each specializes in receiving stimuli from a different part of the color spectrum. By integrating the information received from these specialized cells, the brain makes it possible to discriminate several hundred different hues. A wine taster can take advantage of a large part of this capacity to distinguish a wide range of colors, from yellow-greens to brick reds and purples. In addition to evaluating hue, the wine taster is also interested in the intensity of color as well as the presence, formation, lasting power and size of the bubbles in the case of sparkling wines.
A well-made wine is completely clear and free from floating particles. The color of the wine is influenced by the length of fermentation, time the grape juice is kept on the skins, time in the cask and bottle aging. White wines range from virtual colorlessness to pale yellow-green to deeper shades of yellow gold to amber. A distinct green tinge is common in young white wines. Red wines vary in hue from deep purple to various shades of red to mahogany and amber. Rose (pink) wines range from pale yellow-pink to coral, peach and deep pink.
In addition to clarity and color, one looks for body. Body refers to the substance of a wine. One indication of wines body is its color- the deeper and more dense a color the fuller the body. A wines body is measured by swirling it around the glass and seeing how long it takes the wine to flow down the sides of the glass. Full-bodied wines are heavy and come down the sides of the glass in sheers. Medium-bodied wines are less thick and break into “Legs” (lines of colorless glycerin) as they flow down the sides. Light-bodied wines are not heavy and will not cling to the sides of the glass when swirled.
Smell is the most important sense associated with wine appreciation. Our appreciation of wine is mainly due to its odors. The sense of smell is the most sensitive and versatile sensory evaluation tool.
The sense of smell is used both when actively inhaling the odors of wine and while holding wine in the mouth to taste it. This is because the flavors that are experienced are primarily due to odors that reach the nose when the wine is held in the mouth. Humans can recognize the off-odor of hydrogen sulfide in concentrations of three parts per billion – the equivalent of locating a particular family of three in China. Even smaller amounts of the compound that accounts for the bell pepper aroma in Cabernet Sauvignon – one to five parts per trillion.
The “nose” or smell of a wine describes the perfume it gives off in the form of esters. Aroma is the part of the smell derived from the grape, as for example a flowery nose. Bouquet is derived from the aging of the wine in the cask and in the bottle as for example, a woody nose. Judge the nose by sniffing the wine in an open glass. The nose can range from very pronounced to moderate to subtle.
Air gets to the olfactory epithelium via two routes: directly through the nostrils and indirectly through the mouth and rear nasal passages as wine is held in the mouth to savor its flavor or during exhalation after swallowing the wine. When people drink, most think of the odors they are experiencing when sniffing through their nose as “smells” and the odors they experience indirectly through the retronasal route as “tastes,” even though moth are really smells. We may differentiate these “in-mouth smells” by calling them “flavors,” according to one definition in the Oxford English Dictionary: Flavor is “the element in the taste of a substance which depends on the cooperation of the sense of smell.”
When tasting and smelling wine, follow these simple guidelines:
- Because fewer components will be volatile when wine is excessively chilled, wine tasters may hold the bowl of a glass of cold wine in their hand to warm the wine to release more odorous molecules.
- Wine tasters swirl wine in the glass to increase its surface area so that the concentration of volatile molecules in the area above the wine will be higher when they put their noses into the glass to sniff.
- Wine aromas often seem more intense when the wines are in the mouth than when sniffing them. This is because wines in the mouth have been warmed up – raised to 98 degrees, compared to the serving temperatures of 40-68 degrees, this releases more volatile components.
- When wine tasters draw air through the wine as they hold it in their mouths, they are increasing the surface area of the warmed wine and enabling more odor-saturated air to reach the olfactory epithelium through the back of the mouth and nasal cavities.
A few items to look for when smelling wine are:
Pleasant nose –
- Fresh nose: wine is pleasant with youthful charm
- Flowery nose: wine is fragrant with intense aroma of lilacs, honeysuckle or other flowers.
- Fruity nose: attractive, fresh quality of ripe grapes, but not grapey
- Fragrant nose: attractive, naturally scented
- Spicy nose: wine has a scent of wood and spice
- Yeasty nose: suggestive of yeast or bread dough
Unpleasant nose –
- Metallic nose: unpleasant, usually due to metal contamination during winemaking or aging process
- Moldy nose: unpleasant nose imparted by rotten grapes, or stale, unclean casks
- Corky nose: distinct smell of cork
- Sulfuric nose: similar to the smell of rotten eggs
- Oxidized nose: stale smell due to exposure to air
- Vinegary nose: similar to vinegar, indicates wine is unfit to drink.
Taste is the most limited of the senses involved in wine tasting. The sense of taste can supply information about only four sensory properties: sweet, sour, bitter, and salty. Saltiness if very rare in wines so wine tasting is usually not associated with saltiness. The brain interprets this information and determines how well balanced a wine is for these tastes. Most of what is commonly called taste of a wine is due to flavors that are actually perceived with the sense of smell. The taste of a wine should confirm conclusions drawn from its appearance and bouquet.
The mechanism of taste stars with saliva. In order for solids to be tasted, they must dissolve. Because saliva coats the entire oral cavity, it efficiently delivers taste stimuli to the 10,000 or so taste buds located on the tongue, the roof of the mouth, the back of the epiglottis, and the tonsils.
Humans are most sensitive to bitterness and least sensitive to sweetness, sensitivities to sourness and saltiness are intermediate. To judge taste, swirl a reasonable mouthful of wine around in the mouth for all taste buds to experience.
The following are some items to look for when tasting wine:
Flavor: intensity and length of flavor reflect quality of the wine.
Dry or Sweet: Sweet wines have a taste similar to a solution of water and sugar. Degrees of sweetness range from very sweet to sweet to semisweet. Dry wines have an absence of sugar and range from semi-dry to dry to very dry.
Tart: Tart wines have an agreeable degree of acidity caused by tartaric acid. The tart taste in wine can be compared to the tart taste of orange juice. Degrees of tartness very from very tart, slightly tart, to lacking tartness.
Astringent: Astringent wines have a bitter taste, similar to cold coffee. A highly astringent wine will cause the mouth to pucker. The astringency is produced by the tannin in grape skins, and varies from very astringent to slightly astringent to lacking astringency. Reds are usually astringent, whereas whites lack astringency.
Balance: At the time when the wine is ready for drinking all the wines components are in harmony, with no excess tannin or acidity.
Aftertaste: The impression the wine leaves in the mouth after swallowing. Well-made wines have a clean, crisp finish. Poor quality wines finish “short” or tail off to a watery, insubstantial end. Top-quality wines have a long finish, often extending to a lingering aftertaste- a flavor that remains in the mouth after the wine has been swallowed.
In addition to taste, the mouth offers a sensation of touch. Through the mouth and nose people respond to the tactile stimuli in wines. These include viscosity, dissolved gas, textures, serving temperatures, astringency, and heat from alcohol, as well as sulfur dioxide content.
Wine tasters refer to the thickness or viscosity of the wine as “body.” For example, wines with relatively high sugar concentrations or high alcohol content have more body and seem more mouth filling. The bubbles of carbon dioxide in a sparkling wine bounce around in the mouth and tickle the touch receptors and in the nose.