Open Monday through Friday, 11:30 a.m. to 2:30 p.m. and 6 to 11 p.m.; Saturday, 6 to 11 p.m. All major credit cards.Reservations.

If you consider the origins of hamburgers and hot dogs, you could say that Washinton is full of German restuarants. But once you consider Alpenhof, you know we have had a lot to learn about what a German restaurant could be.

You would never know it had been a Mexican restaurant a few months ago, this Alpine dining room, its wood paneling now looking typically Bavarian. The long bar is hung with tiny flags, above them a balcony, to the rear a raised and curtained dining alcove. The Alpine style reverberates from the large fieldstone fireplace to the flowered cushions tied to the seats, echoes in the soft music, repeats in the waitresses' dirndls and the waiters' vests. You are not required to wear a coat and tie, but you are tempted to wear lederhosen.

The look is German, the mood is German, the waiters' accents are German, and Alpenhof has been drawing some German clientele. Washington is full of ethnic restaurants, but few of them create such a total ethnic environment. And few restaurants in Washington present such high style at such reasonable prices.

A German restaurant leads one to consider beer. On tap at Alpenhof are Lowenbrau, Wurzburger and Beck's from Germany, served in sizable glass mugs. Heady golden Austrian beer is available in bottles, to be poured into Pilsner glasses.

From beer one inevitably thinks of food, particularly the spicy, piquant sort that is the right foil for beer. The appetizers at Alpenhof hit the right tang, the most remarkable being head cheese, that slightly vinegary mosaic of tongue and less-identifiable meaty bits in a shimmering, clove-scented gel. It is cubed and tossed with onions, garnished with gherkins, eggs and tomatoes, nearly a meal in itself. Herring is very good, very briny, rolled around pickle spears as rollmops. Rareties in Washington are Swiss air-dried beef, thinly sliced and garnished with horseadish, and smoked eel - so rare, in fact, that the kitchen was out of it until the next week.

While the soups are an interesting variety - oxtail, liver dumpling, potato, onion and goulash - they fell just short of what they might have been with a little more devotion. Goulash soup, for instance, was generous with meat and brave with high quality paprika, but the paprika retained a raw taste that could have been easily rectified in the kitchen.

Think of a German kitchen, and wiener schnitzel and sauerbraten come to mind. At Alpenhof these particular dishes lack character, so seek the less obvious German representatives. Wiener backhaenchen, for instance, is chicken treated like wiener schnitzel, crumbed to a golden flaky crust, but emerging juicier than its thin veal counterpart. Both are attractively garnished with anchovy rolled around capers and centered on a lemon slice, accompanied by lingonberries, the European cousin to cranberries.

Roast pork may be the best choice of all. Thickly sliced and pale, very faintly herbed, it is delicate roast pork the likes of which we hardly find in restaurants any more. The menu also lists smoked pork loin, trout, liver, brochettes and several steak variations, and at lunch boiled beef cooked to an unfortunate dryness. Much attention is devoted, as one would expect, to delicatessen meats both hot and cold weisswurst, knockwurst, bratwurst, landjaeger, legerkaese, and on from there. Some of them taste too Americanized, without the bite and texture one would find in Germany, but the country-style schweinswurst comes close. Even better than the wursts are their accompaniments. The winy, caraway-studded sauerkraut is outstanding, the fluffy bread dumplings as light as quenelles. Cold potato salad is tangy, its only deficit that it had been refrigerated too long, All the side dishes exhibit personality the chewy golden knockerl, the lightly browned hashed potatoes, yellow squash with crimson pimento, mildly sweet red cabbage. The a la carte tomato salad, though its basic ingredient not nearly as fine as the small German tomatoes, is artistically arranged and pungently dressed.

For dessert it is wise to ask which are made on the premises, for the commercial bakery products are as bland as they are beautiful. The in-house production of apple strudel, however, is flaky and tart with full-flavoured apples as if it had come from a Bavarian bakery. Black Forest cake was also said to be made in the kitchen, but it was unavailable.

And there is the rub. As pleasant - and reasonable - as the Alpenhof is, it holds out even greater promise, and falls short of fulfilling it. One evening at dinner the smoked eel was out, the weiswurst and bratwurst unavailable. The Black Forest cake was gone early in the evening. The major frustration, however, was in the wine list. At first look, it was extraordinary, the range of German wines of good years being offered for prices like $4.50 to $7. On sighting a trockenbeerenauslese being sold by the glass for $5, we immediately reserved a glass. Not possible. They were no longer selling it by the glass, didn't even have it in stock any longer. But they hadn't slipped it out of the plastic pages in the wine list. No wonder; if they did that, the wine list would look emaciated, for wine after wine was no longer available.

As delightful as Alpenhof can be, it has further to go, deeping its kitchen and wine cellar supplied, everseeing the waiters, who are unfailingly cheerful but failing in removing empty glasses from crowded tables and refilling water glasses. Rapid and personable service are not sufficient when they bring the wrong dish and never get around to replacing it with the right one.

Alpenhof goes to extra lengths, lengths such as offering a choice of three white house wines, including liebfraumilch. And sometimes it overreaches, falls short. But somehow allthese merits and flaws add up to a gemuetlich gestalt.