Beer is a more than a thirst-quencher: It is virtually a national pastime. Summer celebrations are incomplete without it. We carry it wherever we go, in knapsacks, picnic baskets and ice chests -- by the six-pack and the case.

Despite this consumptive accolade, many people feel that American beer, like the proverbial apple pie, is not what it used to be, that it has become standardized to the lowest common denominator.

As a result, some have turned to home-brewed beer and found it less expensive and better-tasting than commercial varieties.

Moreover, it is legal. Public Law 95-458, which went into effect February 1, 1979, states that any adult may produce up to 100 gallons of beer per calendar year for personal or family use -- 200 gallons if there are two or more adults in the household.

Terry Robinsion of Alexandria -- who started brewing beer back in 1958 and provided the formula which follows -- believes that home brewing is a simple operation with almost immediate rewards: "because you can drink your beer within a month from start to finish."

Man has been making suds for over 8,000 years by fermenting the extract derived from cereal grains or starchy materials. Most cultures developed some form of alcoholic beverage. When land was not fertile enough to support grapes, as in northern Europe, mead -- a honey wine -- and beer became popular.

Most beers are made from barley, flavored slightly with the bitterness of hops. When the barley sprouts, a complex of enzymes are produced which facilitate the conversion of starches into sugars, which are readily accessible to fermentation by the yeast cells. The sprouted barley mass is then toasted -- a process called malting -- and the darkness of the beer depends on how much it is toasted.

Hops is a perennial plant, Humulus Lupulus, whose ripened and dried cone-shaped female flowers are added to the beer primarily to counteract the sweetness of the malt. Toasted malt and hops are boiled together until a dark brown sypup extract is produced. For more bitteerness, add more hops.

Yeast is the other essential ingredient in converting the liquid -- or wort -- into a savory beverage. Use a beer yeast, not baker's yeast -- they are different. "You don't want your beer to taste like a muffin, "says Robinson, "so use a 'yeastie beastie' which is specially laboratory-grown for beer."

For the beginner, "robinsion recommends a simple pre-mixed malt syrup extract with hops just add sugar, water, yeast and let it go.

Keep a log of your ingredients, when you added them and the reactions. Later the notes can help refine the process.

Beginner's Recipe [makes 10 gallons]

2 cans Blue Ribbon Malt Extract, Hop Flavored Light 5 pounds white, granulated sugar 2 packets of Superbrau beer yeast 1 1/2 cups sugar for secondary fermentation cold water to make up 10 gallons of liquid Mixing. Premark your vat in one-gallon increments.

Before opening the malt extract, slip off the label and clean the can under very hot water to remove the glue and dirt. Open the can and totally immerse it in a gallon of boiling water to get the malt out. When the extract is very hot, take a pair of kitchen tongs and slosh out the gooey residue. Pour the dissolved malt into the fermenting vat.

Boil a second gallon of water. Add the 5 pounds of sugar and stir until completely dissolved. Pour the sugar solution into the fermentation vat with the malt solution.Place the vat on a low table where it can remain for the duration of the ferment; this avoids having to lift 10 gallons of wort to the table for siphoning. Set your vat in a relatively warm spot with very little fluctuation [ideal temperature: 55 to 60 degrees]. In summer, the basement is fine.

Add cold water to make up 10 gallons of liquid. For stout -- fuller-bodied beer -- add only up to 9 gallons. Add the beer yeast and stir the wort; cover it with a tight-filling lid or plastic snugly taped down. Stir the worth gently every day.

Fermentation. A thick foam appears on the surface during the first few days of fermentation, then subsides. Bubbles continue to rise to the surface and break for several days. As the amount of alcohol increases, it inhibits yeast activity until the sugar is completely used up and bubbling stops.

It will take the wort from seven to 12 days to stop bubbling [closer to seven days in the summer]. After it has stopped, let it sit at least one day or two for the liquid to clarify and most of the yeast to settle to the bottom.

Siphoning. Siphon what is now flat, unfizzy beer into another container. But do not siphon the lees -- yeast deposits -- or you will have cloudy beer.

Secondary fermentation. Take several cups of beer, warm it on the stove, and dissolve 1 1/2 cups of sugar in it. If the yeast is still working, it will start to foam -- this is a good sign. Add the sugar-and-water mix to the siphoned beer and stir it thoroughly.

A word of caution: Two cups of sugar is the absolute maximum. Going over that amount increases the likelihood of exploding all the bottles in the true Prohibition tradition -- when unmeasured amounts of sugar added to the bottles would erupt like Chinese firecrackers.

Bottling. Siphon the sugar-dosed beer into the bottles. Don't fill them to the top: It is imperative to leave 1 to 1 1/2 inches for the gas pocket to form. Cap the bottles using crown caps and a bottle capper. It is easiest with one person filling and one person capping. Store your beer in a dark place or in green or brown bottles.

There is an art to serving home-brewed beer. Americans generally drink their beer too cold to really taste it. But a 45 to 50 degree temperature enhances the flavor.

When pouring your beer, do not roil up the sediment. Pour slowly and continously into a glass. Keep it level, do not tip it back upright before pouring the next glass.

Variations. Robinsion used the following sequence of hop flavored malt extracts in his brewing this past year to produce different taste and body: [1] Blue Ribbon -- 10 gallons water -- 2 lights; [2] Blue Ribbon -- 9 gallons water -- 1 light, 1 dark; [3] English John Bull -- 10 gallon water -- 2 darks; [4] English John Bull -- 9 gallons water -- 1 darks, 1 bitter.

Equipment. Use brewing equipment made of plastic, glazed crockery, glass, enamel dor stainless steel.

For the fermentation vat, a white food-grade plastic container is our best choice. It should have a tight-fitting lid and be a third larger than the amount you are brewing. White is preferable since the colroing agents used in other plastics may leach out during fermentation. Large garbage cans may or may not be safe.

Other items: Siphon tube -- a 6-foot piece of flexible plastic gubing. Sink [or weight] to anchor the tubing and avoid siphoning the lees. Kitchen tongs. Large brew kettle in which to dissolve first the malt, then the sugar. Wooden spoons: a long one to stir the wort and a smaller one to stir the malt and sugar solutions. Crown caps: their jagged edges are pressed back during the capping procedure, giving a close fit. Bottle capper, ranging in price from the hand variety at $4.75 to the adjustable lever-arm types, costing up to $31.95.

Bottles. You need approximately five cases of regular, returnable beer bottles to hold the first batch of 10 gals. Commercial bottles are designed to withstand the pressure of secondary fermentation. You cannot use twist-off or non-returnable bottles since they will not seal properly resulting in flat beer.

Ask a bartender to save you his bottles; drink your way through a few cases of beer with returnable bottles; buy cases of returned bottles from a beer distributor [for the cost of the deposit, 75 cents a case] or from a wine-supply distributor [for the cost of the deposit, 75 cents a case] or from a wine-supply shop [a case of used quart bottles is $4.50 at the Wine Cellar].

Cleanliness. The smallest amount of dirt, bacteria or mold can spoil a brew. Clean all equipment thoroughly in scalding water, and repeat the process before and after you use any piece of equipment. Hardened yeast deposits are particularly difficuilt to clean, so rinse the fermentation vat an beer bottles immediately after use.

Before using any new plastic equipment, clean it with a strong solution of baking soda and very hot water. Use only a plastic scouring pad to clean the plastic fermenting vat. Never use soap on any brewing equipment; detergent can be used, but it must be rinsed thoroughly. Use the fermenting vat only for beer or winemaking.

These area shops carry beer-making supplies: The Cellar, 10314 Main St., Fairfax, Va., 591-4668; Wine Hobby Shop, 36 Market Space Mall, Annapolis, Md., [301] 268-3317. Or mail-order from these suppliers [free catalogues available]: Wine-Craft, 3707 Valley Hill Dr., Randallstown, Md. 21133. [301] 655-0529; Wine Hobby, Box 396, Hagerstown, Md. 21740. [301] 797-8070; Semplex of U.S.A., P.P. Box 12276, Minneapolis, Minn. 54112. [612] 5220500.

For additional information about brewing, try "The Beginner's Homebrew Book," by Lee Coe, which describes the basics in a simple, straightforward manner. CAPTION: Picture 1, no caption, by Don Carstens for The Washington Post; Picture 2, no caption