Alcohol
Isolated, alcohol smells sweet. Give the wine a good swirl for a few seconds and pop your nose in the glass. If you actually smell something sweet that reminds you of rubbing alcohol or feel what seems like a heat-driven tickle in your nose, the alcohol is too high for the style of the wine – it’s not balanced. You’re not supposed to notice the alcohol, it’s just supposed to be there.

The mouth-feel: Do you notice that your mouth feels warmer than it did before you sipped the wine? That's the alcohol talking and in a very pleasant way. If it's quite warm, or almost hot, the alcohol content is on the high side. If you actually taste the alcohol or feel like a fire-breathing dragon, it’s too high, not balanced. It seems to be most noticeable in the back of your throat. The alcohol also adds an oily, viscous sensation.

Why do you care? Alcohol gives the wine a great deal of its body or “heft.” A wine that’s meant to be robust in style feels thin and unsatisfying on the palate if the alcohol is too low. Alcohol is yet another preservative, which explains why Port-style wine can live so long in the bottle and actually keeps better than table wine once it’s opened (sugar also helps in that regard).

The source: The sugar in the grapes at harvest. In many parts of the world adding sugar is permitted. It’s called Chaptalization. During the fermentation the sugar is converted to alcohol.  

Descriptions: Warm, hot, weighty, sweet

Sugar
Well, this one’s easy – we all know sweetness, right? And that “dry” is the opposite of sweet? Sweetness also has a pleasant, slippery sort of mouth-feel.

Since sugar is so familiar, this is a good time to talk about perception vs. reality. The level of acidity can really play games with your head in gauging sweetness. It makes the wine seem less sweet than it is. Sparkling wines called "brut," for instance, are considered dry, but they may actually have as much as 1.5 percent sugar (our threshold for noticing sweetness in wine is most often at about .5 percent). They taste dry because they are so high in acid.

Try making some overly-tart lemonade and give it a taste. Then add a little sugar. Keep tasting and adding sugar until you reach a pleasant balance. Notice how the sugar has softened and rounded out the acid sensation? The acid level hasn’t changed, but your perception of it has.

Fruity flavors can also trick your palate into detecting sugar that isn’t actually there. The phenomenon is called auto-association.

If dry is .5 percent or less, off-dry can be up to about 4 percent sugar, medium sweet up to 10 percent sugar and anything over that is very sweet, indeed. But our perception? That’s another matter.

Why do you care? Who doesn’t love something a little sweet from time to time? Plus, besides its rounding effect on overly tart wine, a bit of sugar can cover a lot of sins in the production of inexpensive wine, and it’s another of Mother Nature’s natural preservatives.  

The source: The grapes. In most cases the sugar in wine is residual, unfermented sugar because the fermentation was stopped before the yeast converted all of the sugar to alcohol. In some cases, the winemaker ferments to dryness and adds back grape juice or grape-juice concentrate to sweeten the wine.  

Descriptions: Sweet, syrupy, off-dry, cloying, doux, Extra-Dry (sparkling wine), demi-sec (sparkling wine)

Antonyms: Dry, austere, Brut (sparkling wine), Extra Brut (sparkling wine), Brut Nature (sparkling wine), Zero Dosage (sparkling wine)     
 
Body
It’s all about mouth-feel and weight. Milk products make a good analogy:

•Light = skim milk
*Descriptions: Light, hollow, thin, lean, watery
•Medium = whole milk
•Full-bodied = heavy cream
*Descriptions: Heavy, full, fat, fleshy, lush, unctuous, concentrated, substantial

When the wine is balanced, the flavors, body and the relative level of the components interact harmoniously. Since alcohol gives wine body, a glass of red Bordeaux from a poor vintage that’s only 10.5 percent alcohol may feel thin and unsatisfying on the palate. Conversely, a Napa Cab from a hot vintage better have plenty of flavor and body to stand up to 15 percent alcohol. Otherwise, you will have spent a lot of money on something that makes you feel like a fire-breathing dragon.

The source: Mainly the alcohol and grape extracts (red); barrel-aging can increase the body due to evaporation.

For more wine tasting information from Nancy, check out her blog: thetastinggroup.com.