It is 9 o'clock in the morning and Mario and Biaggio, the snack bar's two "baristi" or barmen, are washing cups and cleaning up the "espresso machine" after the first morning onslaught and in anticipation of the day's second surge, the mid-morning coffee break.

Like almost everywhere else in the coffee-drinking world, coffee prices have shot up here in recent months. But in Italy, where the "tazzina" (the little cup of espresso) is sacred and coffee drinking is a cult, consumer reactions so far have been sluggish.

Without 'il cafe' the average Italian just cannot conceive of life," one Roman coffee freak commented dramatically. he explained that while most bars serve other hot beverages such as tea, hot chocolate and chamomile tea, such alternative hot drinks are considered poor substitutes that cannot begin to offer the stimulative and social qualities of good espresso coffee.

Indeed, coffee-drinking in Italy is a time-honored custom that makes the American habit appear luke-warm by comparison. In economic terms this means that coffee is basically an inelastic product here. The price may have increased but the corresponding drop in consumption has so far been minimal and both bar-keepers and grocers think sales, which recently dipped some, will soon be back to normal.

After all, the average Italian begins his day with straight coffee or caffe-lattee (cafe au lait) at home, then proceeds to an "espresso" downstairs in the local bar before starting work and follows with a third cup sometime in mid-morning when he usually vies nosily with friends and colleagues for the right to pick up the tab.

Another "caffe" is generally downed after the heavy midday meal. And real coffee stalwarts will probably have another shot late in the afternoon and, in the case of bona fide fanatics, again after dinner.

Moreover both the forms and languages of coffee are extremely specialized and varied here. The "cappuccino" (coffee mixed with frothy, vacuum-pressurized milk) that Italians drink only in the morning is often referred to as a "cuppuccio" - which in Italian also means "hood" - and can be asked for either "acuro" or "chiaro" (light), either "bollente" (boiling hot) or "tiepido" (lukewarm).

Espresso, too, comes in various sizes. A caffe "lungo" approaches the brim of the classic "tazzina" because it is made with added water. A caffe "ristretto" barely covers the bottom of the cup because the normal 6 1/2 to 7 grams of coffee is brewed with even less. And a caffe "hag" (pronounced "aag") will give you caffe without caffeine.

The quality of coffees is also stressed. This means that certain bars (in Rome they are"Sant' Eustacchio" and "La Tazza d'Oro," both near the Pantheon) are likely to win a reputation as a coffee-drinker's mecca.

The emphasis on quality also means near-religious rites for home preparation and washing up. For home use there are two types of coffee pots (Neapolitan and mocca) for those who have not yet spent $100 on a portable espresso machine. In both cases the coffee is to be prepared with cold water only and the dirty pot is to be washed with cold water alone and left open to dry.

A cup of espresso, furthermore, is to be drained at a single gulp and not sipped gingerly as foreigners are wont to do. Down South, in cities like Naples, the ceremony is even more complex. There, for example, a real connoisseur will never, but never, raise a "tazzina" to his lips without first having cleansed his plate with a tall glass of water.

With centuries of ritual behind it, the Italian coffee habit will thus be difficult to change. The first big price leap in 1975 to 1976 season led Italians to import 10,000 more tons of coffee than they had the year before. And an official at the Italian Ministry of Foreign Trade says a 10 per cent drop in sales this January is "unfortunately" likely to remain stationary. "I can't see Italians adopting any kind of coffee substitute or partial mix," he said, "which is too bad seeing that the present world price of $3.87 a pound is likely to make a gigantic hole in our already troubled balance of payments."

He added that so far Italians seem to have adapted to the current crisis mainly by changing the composition of their bland. Last year 30,000 less tons of Brazillian coffee were imported while imports from Zaire, the Ivory Coast, Uganda, Cuba and Kenya increased.

Daily habits, however, have changed only slightly. "Most of my steady customers come in at least four times a day," says Oreste, a former film production manager who now runs a small bar not far from the Trevi Fountain. "Some people have cut down on their daily intake by perhaps one cup," he admits. "But as of today my total coffee turnover has fallen only slightly, from about eight pounds a day to slightly less than seven."

That small drop in consumption was in part the result of a 20 lire hike (about two cents) in the government-administered price of a cup of espresso. But most of the current dip came after a major press campaign last month that sought to dramatize the fact that between January and March alone the price of a kilo (2.2 pounds) of quality blend had risen by over 20 per cent.

Italians were urged to boycott coffee fro an entire day on April 14 in the hopes of getting the government to give active support to a plan for coordinated purchase policies by the nine-county Common Market.

Coffee importers, bar managers and Roman merchants joined together in distributing leaflets and posters urging Romans "not to come and have a coffee at our place," a negative play-on-words of the title of a popular book.

But in a country with absolutely no tradition of consumer activity the result was generally uninspiring. True, in some low-income neighborhoods where left-wing parties have sensitized public opinion to such issues, there was a temporary drop in coffee consumption. "My husband joined in because we no longer can afford to spend over a thousand lire (about $1.14) for only an etto (3.4 ounces) of coffee," said a housewife in a working-class neighborhood.

Downtown, however, life - and coffee-drinking - went on more or less as usual. "We did have a couple of people asking for old wartime substitutes like barley or chickory coffee," said Oreste, "but conversion to that kind of coffee production is not a simple matter."

A survey of Rome's first, second and third category bars where espresso prices now range from 200 to 250 lire (capuccino costs more) reveals no slack in the customary coffee trade. But underlying the current complacency is a note of preoccupation.

Oreste, for example, has still not raised his prices from the old 180 lire per cup to the current standard price tag of 200 lire even though he is currently brewing expresso as a slight loss.

"I guess I'll have to get around to it sooner or later," he said. "But for a bar like mine which makes most of its money on coffee, a new increase might haye some kind of an effect. It's not likely," he added, as a group of blue-overalled workmen came in shouting for "il caffe," "but one never knows."