Diving instructor Christian Ekstrom said the bottles are believed to be from the 1780s and likely were part of a cargo destined for Russia. The nationality of the sunken ship has not yet been determined.
“We brought up the bottle to be able to establish how old the wreck was,” he told The Associated Press. “We didn’t know it would be champagne. We thought it was wine or something.”
Ekstrom said the divers were overjoyed when they popped the cork on their boat after hauling the bubbly from a depth of 200 feet (60 meters).
“It tasted fantastic. It was a very sweet champagne, with a tobacco taste and oak,” Ekstrom said.
The divers discovered the shipwreck Tuesday near the Aland Islands, between Sweden and Finland. About 30 bottles are believed to be aboard the sunken vessel.