The keg was tapped on the 172nd Oktoberfest beer party on Saturday, which is expected to draw some 6 million people to the fairgrounds in the southern German city of Munich during its two-week run.
One day before Germany went to the polls, Munich Mayor Christian Ude, a Social Democrat, cracked open the first barrel at the stroke of noon with the cry "O'zapft is!" (the keg is tapped) and presented a giant glass to State premier Edmund Stoiber, a member of the conservative Christian Social Union.
Thousands of revelers gathered in the Schottenhamel tent -- one of 14 on the fairgrounds -- cheered despite a steady drizzle.
"We want two weeks of beautiful weather and a peaceful festival, without violence, and everyone to have a great time," Ude said.
Bavarians donned their traditional Tracht (national dress) -- Lederhosen (leather pants) and embroidered braces for the men, long pleated smocks and low-cut blouses for the women -- as tourists from around the world came to glimpse a peculiar slice of German culture.
"I love the outfits, the costumes, and I especially the size of the beers," said Jonah Hartley, a 24-year-old builder from Cambridge, England.
Despite the general election yesterday, 1 million people are expected during the first weekend of the festival alone, consuming beer and sausage served up in giant tents to the oom-pah-pah of brass bands.
Each visitor drinks around one liter of beer on average, organizers said.
Bavaria, a conservative state, was expecting to toast the victory of Christian Democrat candidate Angela Merkel over Chancellor Gerhard Schroeder at the event last night.
Stoiber, respecting the Oktoberfest's long tradition of not mixing beer and politics, said only that he was "satisfied" with the conservatives' chances in the election.
The first Oktoberfest was held in 1810 to celebrate the marriage of the prince of Bavaria, the future King Ludwig I, to Princess Therese of Saxony-Hildburghausen for whom the park grounds are named. It has been cancelled only 24 times, for outbreaks of war or cholera.
For the 172nd year of the Oktoberfest, restrictions on the volume of music have been imposed until 6pm, although at its newly-set level of 85 decibels it is still as loud as an articulated truck.
The Oktoberfest format has been exported to the Malaysian capital Kuala Lumpur and the Taiwanese capital Taipei, and Bavarian authorities have struck an agreement with the southern Chinese industrial province of Guangzhou to hold one there.