It's not a magic elixir that builds strong souls and guarantees immunity from sin. But the milk produced by the pope's dairy herd must certainly taste like heaven.
Each morning, a truck with Vatican license plates delivers 120 cartons of the milk to three local coffee bars.Within hours, they're sold out.
"We don't have enough to meet the demand," said the waitress at Mirko's Bar on Via Garibaldi who gives her name only as Manuela. "It sells like hot cakes."
Milk from holy cows?
Actually, it comes from 30 black-and-white Holsteins on a small farm inside the walled compound of the 17th-century papal palace.
Until recently, this thriving dairy operation was the least-known of the public services offered by the Vatican, which also runs a postal service and pharmacy in Vatican City in the heart of Rome.
The farm at Castel Gandolfo, the pope's hilltown holiday residence, covers about 60 acres on the palace grounds and is surrounded by pine, cypress and olive trees. In addition to milk, the farm produces eggs, olive oil and other products for distribution at the Vatican market, open only to Vatican employees and their families.
The farm has been operating since 1933, but the sale of milk to the public began only six years ago.
The cows produce 130 gallons of milk a day, most of which is transported to the Vatican market, and the remaining 31 gallons to the three cafes.
Few people outside of Castel Gandolfo knew about the milk operation until the Rome newspaper Il Messaggero recently published an article titled "The Pope's Milk, How Tasty."
Since then, people have been traveling 15 miles from Rome to sample the product at the two bars in Castel Gandolfo and one in nearby Albano. The milk comes in distinctive yellow and white cartons with the label "Fattoria Ville Pontificie," meaning the Pontifical Villa Farm.
"Our regular customers are getting upset because there's not enough left for them anymore," said Manuela, as she served up a cappuccino with steamed Vatican milk. "They're asking us to put aside cartons for them."
One client, Rita Grecco, said she is taking no chances.
"I buy two or three liters every day," she said.
The bar also receives 30 cartons of milk a day from another supplier but usually manages to sell only five of them, Manuela said. Price is not a factor. Both brands cost the same, about $1.10 dollars a liter.
Even before its popularity reached outside the area, the locals put their faith in the Vatican milk when they were looking for products free of contamination following the 1986 Chernobyl nuclear disaster.
The milk was considered safe because the cows were kept inside their barns and fed hay and fodder that had been stored in protective silos, said Saviero Petrillo, director of the papal village.
"There was a much greater demand, especially from mothers with young children," he said. "Today, in an era when there's a lot of emphasis on ecology and the environment, people are more conscious of products that are healthy and genuine."
Vatican services seem to have a special allure for Italians and foreigners, who view the tiny city-state as a rock of efficiency in a land often associated with confusion and chaos.
Many post their mail at the Vatican, knowing they can cut days, even weeks off the delivery time of a letter abroad. In 1988, the Vatican post office helped give the city-state a $13 million surplus.
But does the Vatican's milk taste better than others? Some customers swear it does.
"It's creamier," said Grecco.