There are eight 45,000-liter drums lined up at the edge of the yard of the Ostankino Experimental Factory for Non-Alcoholic Drinks. Whatever is in them, it is not kvas.


The tanks have outlasted their usefulness by at least two years, said plant worker Tatyana Zhdanova dolefully, as the sweet brown liquid cascaded through a large hose into the back of a truck. Ever since foreign interlopers such as Coke and Pepsi arrived on the scene, consumption of Russia's second national drink has been sliding downward fast, said officials at the city's main kvas plant.


She points up at a single 25,000-liter reservoir. Then, in contrast, she looks at a stumpy 10,000-liter holding tank.


"This is all we need these days," she said, shaking her head in disgust.


In June, Interfax published an opinion poll claiming that kvas remains the most popular non-alcoholic drink among Russians. The beer-like drink, which is made with fermented yeast, has been a vital part of Russia's summer culture for generations -- praised for its nostalgia quotient and its miraculous healing properties. When Russia converted to Orthodoxy, Prince Vladimir supposedly ordered barrels of kvas (from the verb kvasit', to ferment) to be ladled out to people in the street by way of celebration.


As this summer heated up, 19 percent of 1,209 Russians across the nation still said they preferred the drink to Pepsi, Fanta or Coke. But that is little comfort for the city's kvas producers, who have watched their trade dry up over the last two years.


The factory used to supply around 500 kiosks with about 3 million liters of kvas a summer, but now that number has dwindled to 150,000 liters. The price has climbed from kopeks to about 500 rubles a liter, which is comparable to most other soft drinks.


Sergei Mironov, the factory's assistant director, said kvas could make a comeback if there were money for advertising.


"If we had the money for advertisements -- posters with a hand holding a bottle of kvas, for instance -- then we would sell more," he said. "It's a tough market."


From the truck, the factory's kvas will be handed over to kiosks across the city, where kvas is distributed razlyv, or on tap, into customers' bottles. The kiosk business, too, has dropped off dramatically, vendors say.


Ten years ago, the kvas distributor on Ulitsa Babushkina Petchika sold 900 liters per day, at a price of 6 kopeks apiece, said manager Andrei Bystol. Now, he is lucky to sell 350 liters, at a rate of 500 rubles. Another outlet in south Moscow said its trade is down from 1,200 liters a day five years ago to 600 liters a day now. Yeva Strakhova, commercial director of the Russian Kvas store on Ulitsa Menzhinskovo, said it has become vastly more practical to make kvas at home. Her shop's sales have dropped from 1 1/2 tons a day to 300 liters.


"It's more expensive than beer now," she explained. "No housewife would pay that much for something she could make herself."


But all of them defended the honor of the drink, and the part it still plays in Russian life.


"Our kvas is the best in the region, possibly in the country," said Lyudmila Yakushina, who has worked as a manager in the Ostankino factory for 15 years. "I love our kvas. Our kvas is real kvas. It's Russian kvas."