THE FIRST thing to know about tasting wine is what you hope to get out of it.

You may be looking for wines to drink now, which means that the wine must be pleasing, and should probably taste more appealing than the wine you would lay away.

Perhaps you are looking for the best value, and a good way to do that is to taste wines blind, simply placed in order of price, so that if something tastes good early in the testing, it is clearly a better value than something that tastes good at the end of the tasting.

Maybe you're looking for a "house wine," either for your own house or a restaurant.

Are you collecting all of the available zinfandels to see which one you like the best?

Are you tasting everything in sight just for the sake of tasting?

Are you testing yourself with unmarked wines to see whether you can identify them? (You need someone to pour them for you, obviously.)

Are you a professional judging wines on a panel, knowing that your opinion can have a profound effect on the winery?

The purpose of the tasting will dictate its method. Let's suppose that you're looking at wines to lay away. There are certain elements that should be noted, and they don't necessarily taste too pleasant in a young wine with potential. (By the way, even though people use terms like "longevity" when talking about wines with potential, it is time to break the news that wine is not a living thing. A changing thing, yes; but wine is no more alive than a pickle. It does not reproduce itself--at least not the last time that I looked in my cellar!)

Wines that last for a long time need to have a fair amount of alcohol, which is usually accompanied by some glycerine. A young, alcoholic wine will burn your mouth a little, so in addition to reading the label for the percentage--which is allowed a degree and a half leeway in either direction--try to feel the alcohol. Your mouth is more sensitive than you think. Glycerine can be observed by an increase in body in the wine, and an observable density in the glass.

Tannin is important in keeping red wines for a long time, and is often referred to as the "backbone" of the wine. When the wine is young, tannin will appear as a bitter substance, and will make your teeth feel coated.

Now that we've touched on the burning of alcohol and the bitterness of tannin, it's time to talk about acidity, which will taste sharp in your mouth. Down the road, acidity will contribute to bottle bouquet, but in the early stages, it can be as unpleasant as alcohol and tannin. Makes you wonder why people even try to taste young wines!

Fortunately, another "preservative" of wine is sugar, and the great sweet wines of the world, such as sauternes and late-harvest rieslings from both Germany and the United States, last as long as they do because of their high content of residual sugar. At least these wines are delicious when young, and drinking them too early isn't always a mistake.

Wine tasting involves more than the sense of taste--it involves the sense of sight and smell as well. There is even a tactile sense as the wine enters the mouth. A person who is about to taste a wine should first look at it, then smell it and finally taste it. SIGHT

First, the bottle that the wine comes in should be looked at, as information can be gleaned from the size, shape, color and condition of it.

Second, the label should be examined to see the name and type of the wine, the vintage if any, the producer, shipper, distributor and/or importer.

The third thing to look at is the cork, noting the condition, length and any possible branding or writing.

Finally, we come to the wine. The glass should be held up to the light, or looked at in front of a white background. You should notice the color (hue) and density (depth). (See list of hues below.) One should also look for clarity and even brilliance. Dullness or cloudiness may indicate a problem with the wine, the storage or the service. SMELL

Before smelling a wine, the glass should be rotated so that the liquid will be aerated. This will help to vaporize the bouquet. You should then smell for such elements as cleanliness, freshness, maturity, fruitiness, floweriness, possible woodiness and often the varietal character of the grape. Obviously, not all of these elements will be present at the same time. Faults that can be picked up by the nose include corkiness, oxidation, acetic acid, sulfur dioxide and hydrogen sulfide. Since most of the sense of taste is actually part of the sense of smell, you will know a great deal about the wine before you ever taste it. Your eyes and nose can give you a great deal of information.

Rotation of the wine in the glass will also give you the opportunity to look at the density of a wine and the "legs," which are rivulets of wine that sheet down the sides of the glass and usually indicate higher alcohol or sweetness.

A word of caution: There are many fragrances that are very appealing under normal circumstances, but are a problem to wine tasters. The psychologists call their effect "interference." This can come from perfume or after-shave lotion, aromatic foods or the smoke from a good cigar. TASTE

Once the wine enters the mouth, it should be rotated within the mouth, so that all of the taste buds are exposed to the wine. A little air should be breathed in to vaporize the flavors even more. Flavors will include a range from sweetness to dryness. You should think about the level of acidity, and whether there is any astringency. See whether the wine appears simple and one-dimensional or complex, with many flavors present. Notice also the temperature of the wine, and its weight in the mouth. It may feel light or it may feel substantial. This is known as the "body" of the wine. Faults in the flavor of a wine might include oxidation (previously detected by the nose), excess acidity (which may or may not have been detected by the nose, depending on the kind of acid), bitterness and sometimes a metallic taste.

Remember that the taste of the wine will change with the length of time it spends in the mouth. There are concentrations of different flavor receptors (taste buds) on different parts of your tongue, and you will notice sweetness first and bitterness last. Meanwhile, the salivary glands in your cheeks are neutralizing acidity, so the acidity level appears to change as well. In addition, a mouth that is well oiled with cheese will perceive wines differently than a "virginal" mouth.

You should now think about the aftertaste or "finish" of a wine. The finish may be dry or sweet, and the aftertaste may last for a long time (a long finish) or disappear right away (a short finish). You should then consider the balance of the wine, going back to the original promise made to the nose and then reviewing to see whether that promise was kept.

People who taste professionally, especially when tasting comparatively, should then spit the wine, and not swallow it. Do not be self-conscious about this.

When drinking wine for pleasure, by the way, put all of these procedures aside, and do not be encumbered by this critical analysis.

If you're lining up wines for a blind tasting, remember that the order that the wines are in will affect your opinion of them. A dry wine after a sweet wine will taste very acid, for example. A good wine after a flawed wine may taste better than it would otherwise. It is important to taste the wines in both directions to remove some of these possibilities. There is also the psychological factor of thinking that the person who set up the tasting (if it wasn't yourself) put the best wine first--or last; you can't help wondering about it.

You should also know your own limits of "tasting fatigue." Eventually, with too much alcohol, tannin, acid or even sugar, you will get nose and mouth fatigue and your level of concentration will decline.

If you're tasting in a group, stick to your own opinion, and do not be influenced by a taster who is louder than you are and who likes to dominate a tasting. Be brave.

Try to avoid second-guessing in a blind tasting. You only end up worrying about extraneous things instead of concentrating on the wine.

If it turns out that you've guessed wrong, don't worry about it. Even though there are a lot of stories about fabled tasters who know what side of the hill the grape was grown on, it's not so easy to identify a wine. If you feel compelled to discuss it, here are some handy excuses that you can use:

"My wine was from a different bottle."

"The waiter mixed up my glasses."

"The wine changed in my glass."

"My glass was washed with detergent."

"I just came from the dentist."

"I have a cold."

"The waiter poured a different wine on top of my wine."

"It didn't taste that way at first, but now that the wine has aired . . ." WINE HUES

WHITE WINES: Pale Water White, Pale Yellow Green, Straw Yellow, Deep Yellow, Gold, Old Gold, Amber, Brown/Maderise

As white wines get older, they become darker and tend towards the browner tones. Sweet white wines will usually be more golden than dry white wines.

ROSE' WINES: Oeil de Perdrix, Tearose, Coral, Peach, Pale Pink, Deep Pink, Light Red

Since any wine that has any red color in it at all is considered to be a red wine, rose' wines are technically red wines. Because there are so many hues, however, they are listed separately for the sake of custom and convenience.

Rose' wines vary from very pale, almost like white wines, to wines that have a deep rosy color. These hues will vary with the aims of the wine maker and the grapes that are being used.

RED WINES: Purple, Ruby, Red, Garnet, Maroon, Red/Brown, Tawny, Amber/Brown

As red wines get older, the youthful purple color drops away, revealing orange tones. These wines also darken with age and get browner, while the rim of the wine becomes clear.