WHATEVER YOU call wine tasting, organoletic analysis or sensory evaluation, it's very important to every wine lover. The surprising fact is that such an important detail of wine enjoyment has virtually no standardized method that is universally accepted and used.
Over the years, plenty of people have tried to standardize wine tasting. Each has his own idea about how to standardize it for everyone else but no single proposal has been widely received, especially without misunderstanding.
Let's keep it simple; if we don't I won't get it written. Analyze wine scientifically and you'll find that practically all table wines are 99 percent water, alcohols, acids, tannins and sugars. Perhaps 400 other compounds in varying proportions for various wines make up the other 1 percent. Yet those 400 gems make the difference between Chateau Terrific '45 and non-vintage Vin Plonk -- for they become what our palates recognize as the "overall flavor sensation" of each wine.
Alcohols: The major alcohol in wine is, of course, ethanol. Table wines with low ethanol content have a thin character, and those with too high a concentration often have a "hot" taste. The other alcohols, never present in large concentrations can be considered flavor components, especially in contributing something to the "nose" of the wine.
Acids: Natural acidity in grapes (and new wines) is mostly tartaric and malic acids; after malo-lactic secondary fermentation, the malic acid has changed into softer tating lactic acid, but the tarlaric acid remains unchanged through it all. Tartaric, in fact, remains unchanged through long-term bottle aging as well; I've heard people say that wine acid "softens" with age in the bottle. Not true! (Tannins soften will age, but acids don't change, unless of course the wine is chilled enough to cause cream of tartar to crystallize out of solution.) When that happens, you can see crystals on the cork or in the bottle but, even then, the taste of the wine is not usually changed significantly. Acidity gives the wine its "tart" taste, but equally important, acidity helps to protect the wine from spoilage during fermentation and during aging later.
Tannins or phenols, give the wine its red color, astringent or bitter taste (but not "tart") and much of what your tongue senses as "body" in the wine.
Tannin in wine comes from grape skins, stems (even seeds if they happen to get crushed) -- but also, important to the eventual wine flavor, from barrels the wine was aged in at the winery. Most white wines are lower in tannin than most red wines, but no grape is completely free of it. However, white wines aged in wood (chardonnay, sauvignon blanc and sometimes one or two other white varieties) can contain lots of tannin -- one of the reasons these wines live longer in the bottle than others. Tannins are natural antioxidants and, since oxygen is the great enemy of aging wine, tannins are responsible for extending the life of bottled wine. "Fresh and fruity" white contain much tannin -- and don't taste bitter or astringent and don't have long lives in the bottle.
Taste the sensation of tannin (as astringent or bitter) only at the very back of your tongue; taste the sensation of acid (as sour) only along the sides of your tongue. Distinguishing between the two is very important if you're a winemaker; but if you're enjoying a nice bottle of wine with dinner, it really doesn't make any difference.
Last, and maybe least, tannins have a natural affinity for viruses, and many other proteins. Certain red wine tannins have been shown to react irreversibly with certain viruses to inactivate them. I don't suppose this means anything prophylactically, but if you caught the flu recently, it certainly didn't come from the insude of a red wine bottle.
Sugars: We all say we like our wines "dry," but industry sales records indicate that lightly sweet wines far outsell wines that are completely void of sugar (dry). Ripe grapes have around 20 percent of their weight as sugar, but this is changed into about 12 percent alcohol by the yeast during fermentation. You'd therefore expect a fully fermented wine to contain zero sugar, but that isn't quite true. About 0.2 percent of something remains in fully fermented (dry) wine that analyzes out as reducing sugar. Supposition is that the 0.2 percent more or less, is made up of odd-ball sugars that the yeast can't handle. It really doesn't matter: Normal taste threshold for sugar is around 0.5 percent, so your brother-in-law who claims he can taste 0.2 percent can't.
So how do you evaluate wines by taste? Get a corkscrew and a bottle and use them, one at a time. And take notes.