MENTION "TOAST" to a wine lover and the response surely will be "champagne!" It's mightly evocative, that word champagne: a symbol to attach to celebrations and moments of homage. Surely few of us who plan to toast our way through the upcoming holidays and greet the new decade on bended elbow won't at some point encounter a glass of sparkling wine.

Americans have been drinking more and more of "the bubbly," as Bing Crosby called it in "High Society." In 1978, 25.6 million gallons went into distribution, a 5.7 percent increase over 1977. Despite rising retail prices. consumption continued to increase this year. Nonetheless, there are those who just don't care for sparkling wine. Happily, Santa Claus is not among them. I know that because a young lady who dwells in my house asked, at the age of 4, what snacks were being left for Santa on Christmas Eve. Cookies and milk, she was told. "Santa doesn't want milk," she announced. "He likes champagne." Sure enough, Christmas morning the champagne glass was empty.

Others feel it causes them to become ill.After starting the obvious (that too much of anything can make anyone ill) and the almost as obvious (any wine that is too cheap may be badly made), let it be said that I've been served good sparkling wine when ill and it has made me feel better. Then I've been served sparkling wine when feeling well and it has made me feel much better. Whether it is the psychological lift or the very real stimulation of this delicate but heady carbonated wine, it works for me and I find myself more and more partial to it.

There are many complexities and rituals to sparkling wine, but there is one basic truth that no novice drinker should forget. It always should be served well chilled. Warm champagne is suitable only to be placed in a sauce or an ice bucket. Don't drink it!

Perhaps the first complexity to deal with is the question of what is and what isn't "champagne." The French claim that only sparkling wine made from specified grapes grown within the appellation controlee boundaries in the region of Champagne should be called by that name. The United States has never accepted this restriction, so you will find "American champagnes" on the market. While more than 80 percent of what we drinking is domestically produced and several of our home-grown products deserve to be counted among the world's great sparkling wines, they are not champagne in the true sense of the word. They have characteristics and personalities distinct from the French product, as do sparkling wines made in other regions of France.

What is more important to someone trying to choose a bottle of sparkling wine is the way in which it was produced. The key is methode champenoise. On a bottle of sparkling wine, no matter where made, that means the classic method of production has been used. The wine has been fermented twice, the second time in a bottle that is hermetically sealed.

It's a time-consuming, expensive process (by law in Champagne, at least three years from harvest to release for sale) that produces wines with the delicacy and sophistication one has a right to expect from true champagne. Far easier, for example, is the practice of injecting carbon dioxide into a vat of still wine. It produces bubbles, but you don't have to be a wine steward to taste the difference.

To give a one-minute crash course on the making of champagne: It comes from either red pinot noir or white chardonnay grapes, although two other graps provide a minute portion of the wine. (Champagne from all white grapes is called blanc de blancs. It is more delicate, too delicate for some palates.) For still wines, grapes are crushed and dumped in open tanks where yeasts cause a fermentation in which sugar becomes alcohol. In Champagne, the fermentation is stopped before it is complete. In the spring the yeast, bolstered by a shot of cane sugar syrup, starts to work again. But this time the wine is placed in a bottle and corked. Thus the carbonic acid gas is trapped inside. It will reach a pressure of 90 pounds per square inch, so the important of strong bottles and wire fasteners for the corks should be apparent.

After the wine has aged, the most publicized step in the process takes place. The bottles are placed in racks, cork downward. Gradually, skilled workmen turn the bottles and increase the angle so that the sediment from the second fermentation works its way into the neck of the bottle. Then the necks are frozen in a brine solution, the dirty piece of ice-wine pops out and the bottle is topped off with fresh champagne and another dosage. The intensity of this dosage determines how dry of sweet the finished champagne will be.

The bottle then is sent off to age among the 670 million other bottles currently stored in caves in the Champagne region. Most are blends of wine from two or even three vintages made in such a way to give a distinctive style. Champagne producers set great store in providing consistency of taste. sEventually it will be labeled and sent off.

While secondary fermentation in wines was not uncommon (even today, you may find a mild spritz in badly made still wines), the process could not be perfected until the development of a bottle that could take the pressure and the innovation of corks as stoppers to provide hermetic seals. This came about at the end of the 17th century when, legend has it, a winemaker-monk named Dom Perignon succeeded in taming the second fermentation. He was blind and supposedly reacted to the first taste of his new wine by saying, "I am drinking stars."

Almost immediately, it became the drink of the stars. By mid-century Madame de Pompadour has said of champagne, it "is the only wine that leaves a woman beautiful after drinking it." Champagne has enjoyed favor in high places ever since. But it has not been reserved for the French. First the Russians came to Paris following Waterloo and began shouting. "Bis! Bis" ("More! More!") to get additional bottles of the bubbly (and at that period quite sweet) wine. The zinc-lined bars where they shouted became bistros. After the Russians left the English kept up the chant more discreetly and by the end of the century no civilized indiscretion in Paris or London could be brought to fruition without the aid of champagne.

Is popularity here fell off during the post-Prohibition cocktail era, but the rising tides of affluence and white wine comsumption have brought it to the fore again.

Therefore, in any wine shop, you will find a range of sparkling wines, usually grouped by country of origin and separated by great gaps in price. With the thought in mind that price often is the determining factor in a purchase decision, the Food Section conducted a tasting of 14 sparkling wines that were divided into four price categories.

Most of the wines were blends without vintage date. Vintage year and top-of-the-line champagnes cost far more than our highest price ($14). The vintages currently on sale are 1970, 1971 and 1973. These are years when growing conditions are exceptionally good and the wines should be better than blended, non-vintage bottles from the same producers. The taste distinction is not always as apparent as the price distinction, however. Of the Cadillac wines, Moet's Dom Perignon was the first and is the best known, but other leading houses (as Champagne wineries are called) have their own and are certainly competitive in quality. They are always vintage dated. Of them Ruinart's Dom Ruinart is clearly the best value.

You should look, as well, for a discriptive term on the bottle. If it is "nature," the wine will be very dry, even tart; "brut" means dry, the wine for aperitifs or to drink with most food; "sec," rarely seen here, is mildly sweet; "demi-sec" is sweet and about as far along the scale as you should go. Serve this with desserts or pastries.

Once you have your bottle (or bottles) of sparkling wine at home, there are several other complexities to deal with.

The wine itself is very resilient, but the cork may not be. Severe changes in temperatures may lead to shrinking and a resultant loss of carbonation. Flat champagne is drinkable, but not much fun. Therefore, chill it not more than a day or so before serving and don't risk sticking it in the freezer.

Open the bottle with care. The cork is potentially a dangerous projectile.

Remove the wire, taking care that the cork is not pointed toward anyone, then cover the top with a towel or napkin and either work the cork upward with your thumbs or twist the bottle (not the cork) to lossen it. Slow the extraction so there is no pop. The pop means lost carbonation and less bubbles.

Experts plead with novices to avoid the flat champagne coupe as a drinking glass. Too much surface is exposed and the coupe usually is filled to the rim. They prefer a narrow, tall Glass (best of all, tulip shaped) where the bubbles can drift upward slowly and the level of the wine is an inch or more below the rim. These glasses should be dry, not chilled with ice, as a wet surface tends to kill the bubbles.

What food to serve with sparkling wine? It is superb as an aperitif, by itself or with -- perhaps best of all -- caviar. It goes very well as the wine with a cold lunch of supper featuring lobster or chicken. It accompanies some hot fish dishes (oysters or scallops in a sauce made with champagne), though not all, and -- in its demi-sec or midley sweet form -- is ideal with cakes.

You will never get the original cork back in a champagne bottle, but an ordinary wine cork for metal recorking device will keep out the air and the open wine will survive a day or more with its sparkle intact.

The testing results given here were obtained in a "blind" tasting. A scale of 1 to 20 points was used, with 20 representing a "perfect" wine. None of the participants knew the identities of the wines, nor the price categories. The ideal brut champaign should b crisp to the taste with a clean bouquet that suggests grapes but not sweet fruit. It should be at least faintly golden in color and the bubbles should be small, concentrated and dissolved slowly over a relatively long period of time.

Perhaps the most significant result of this tasting was that the four French champagnes were the four most popular wines. The fifth, Domaine Chandon, is made in California by a firm owned by Moet & Chandon. The prices given were those at the store of purchase, Chevy Chase Liquors. They may vary at other wine shops.