Five years ago, the Katzes of Kensington were on a fishing vacation in Wisconsin. They stopped one night at a campsite. The youngest Katz, Victor, then 8, was dispatched to the general store to buy a few things.

"I walked in and noticed that the owner had beer cans all over the place," Victor Katz recalls. "I said to myself, 'Why would he collect beer cans? He must be crazy.'"

It might indeed seem so, since most people consider the can merely the surroundings, and the contents the point. But something bit Victor Katz that summer day. It stayed below the surface for years. Eleven months ago, it sprang forth.

"Dad," announced Victor to Larry Katz one day, "I wanna collect beer cans."

Holy Heineken!Hadn't this lad grown up in a family of only occasional drinkers? Wasn't it true that this cherubic 13-year-old had barely ever tasted beer? Wasn't this the same kid who had been indifferent to stamps and coins and baseball cards all his life?

Well, yes, yes and yes. But his parents agreed, and now they are glad they did. For Victor Katz has proven to be one determined dude. He has a collection of beer cans that would make a lobbyist for the aluminum industry proud.

Victor Katz doesn't have the biggest stash of cans in the world, or the country, or the state of Maryland, or even the Rock Creek Palisades neighborhood where he lives. Still, as of last week, Victor had collected 262 beer cans, or more than 20 a month since he started. That would have to make him a leading contender for Beer Can Rookie-of-the-Year, if there were such an honor.

But numbers are not really the point in the case of Victor Katz. For him, beer cans are the consuming passion.

A typical Sunday will find Victor and his mother driving along a main drag somewhere in Montgomery County.

Every few hundred yards or so, Gerry Katz will pull onto the shoulder and Victor will clamber out. There, in the ditch, will lie a feast of Schlitzes, Nationals, whatevers. Even if he already has these models, Victor will pick them up as possible material for trades. "At least we're helping the environment," Mrs. Katz says.

Every couple of weeks, Mrs. Katz and Son will hit the flea markets. Particularly at their favorite, in Frederick, the Katzes are likely to find an obscure can, and old one, a rusted one, maybe even a rare one. They pay an average of $1.50 a can. "That's a lot cheaper than some of the things kids want today, I'll tell you," said Gerry Katz.

Victor's collection has been fruitful and has multiplied. It now consumes about a fourth of the basement of the Katz home at 11122 Dewey Rd.

The collection is laid out in neat rows, and in alphabetical order, on plywood shelves that Victor built. Nearby he keeps duplicates he uses in trades, and a card file describing each can. On the walls and othe nearby shelves are Victor's satellite collections, of mugs, coasters, posters and pitchers.

About half the collection is big-name brands. The rest is local beers from all over the country and world. The collection runs the alphabetical gamut from Alps Brau of Chicago to Yuengling Premium of Pottsville, Pa. It includes cans of 10 countries, five sizes,rs.

Victor's favorites? He admits to a soft spot for his five Scottish cans, all of which once contained Tennent's Lager.

The back of each features a blonde named Penny, in different costumes, or lack of them. Victor has the whole set - Penny in the morning, at noon, at the end of the day, in the evening and at night. What Penny has is very plain.

Another unusual can is one that once held Amana Beer, pride of Amana, Iowa. The can is a real period piece - from the period before the marketing boys decided that beer cans should explode with color. Victor's Amana is solid black, with plain white lettering. It looks like it should have held motor oil.

You say you swill Schmidt's of Philadelphia? Bet you didn't know there was a Schmidt also, without the apostrophe or the S, from La Crosse and Sheboygan, Wis. The two Schmidts are side by side on Victor's shelf.

Victor even has 12 ounces of history - in the form of a can of Prinz Brau dated Sept. 22, 1976. Prinz is the first beer produced in Alaska, and Sept. 22 was its debut day.

But Victor Katz's favorite can never held beer. It is a 1960 Coke can, all red and silver, the first can into which Coke ever put its famous product. The can occupies a place of honor: Top shelf, center. For Victor, it is there as a matter of loyalty. "It's just about all I drink," he said. "I don't think I could ever like beer."

The beer that Victor's cans once held is often drunk by nobody. "My dad has a tough time finishing one of those," said his son disdainfully, as he fingered a seven-ounce Rolling Rock. More often than not, Victor simply dumps the beer down the drain, after carefully opening each can on the bottom to preserve its looks.

Neither Victor nor any serious collector collects full cans "because 1,000 12-ounce cans would weigh close tt would threaten the continuing existence of Victor's shelves, and might discourage some of his "connections" - relatives around the country who now provide him with local empties.

Victor Katz is aware of how costly his habit is, and with an allowance of only $1 a week, he must often rely on his mother for funds. He knows that selling his collection some day would more than reimburse her, but he disclaims any interest in profits.

"I'm aiming at a couple of thousand by the time I'm 20," said Victor. That's cans, not dollars. "I just want a good collection. There are lots of ways to make money."

Right now, Victor admits, his collection is "at a bit of a standstill." He is weak on cans from the beer-happy Pittsburgh area, and he must wait until the summer, when his mother has agreed to drive him there, with side stops in West Virginia and western Maryland, to flesh things out.

On the local front, Victor is busy negotiating with several embassies so he can upgrade his foreign stock. In his spare time, he pores over collectors' bulletins and magazines, always on the lookout for something that, with a little bath of oxalic acid, will look as good as new.

So cans are Victor Katz's life, and he claims, with 13-year-old certainty, that they always will be. When he goes away to college, the collection "comes with me." If a potential spouse doesn't share his hobby, or condone it, "I won't marry her."

The crowning stroke is that Victor is "sure" he wants to be a veterinarian. "Because a veterinarian in Ohio has the biggest collection in the state," Victor explains.

"I know some day I'll stop getting interested in it," says Victor Katz, pawing his page-boy out of his eyes. "But then I'll just go back and get interested in it again."