A properly filled mug known as a Maß is rare at Oktoberfest, according to testing by the League Against Fraudulent Pouring (VGBE), which visited 12 separate beer tents to order almost 100 mugs.
Instead, many Maß, which cost about €9 each on average, are only being filled to 90 percent, because Munich's government allows a variance of up to 0.1 litre, the organization said.
“The tolerance level has to go,” said the VGBE's president, Jan-Ulrich Bittlinge, who called the results of the test “sobering.” “We ordered and paid for seven mugs in every tent. But, in fact, we received on average only six litres of beer.”
Some results were particularly bad: In one tent the mug only contained 0.73 litres of beer, meaning the customer was cheated out of €2.43 worth of beer.
VGBE, which was founded more than 100 years ago to protect beer drinkers' rights, has become famous for uncovering beer-pouring fraud throughout the country. Its roughly 4,000 members are particularly active during Oktoberfest, but have also appeared at festivals in Köln, Stuttgart and elsewhere in Germany.
In addition to using typical tools, such as tape-measures, at this year's Oktoberfest, the organization's members are using a smartphone app called “Beer Inspector,” which can calculate beer levels by analyzing a simple photograph.