A bottle of wine recovered intact four years ago from the 1864 wreck of a Civil War blockade runner that sank off the coast of Bermuda has been uncorked and sipped by a panel of experts on Friday during a food festival in Charleston, South Carolina.

The verdict: A heady sulphur bouquet with distinct notes of saltwater and gasoline.

The wine was uncorked at a Charleston Wine and Food event titled From Deep Below: A Wine Event 150 Years in the Making.

About 50 people bought tickets to watch as a panel of wine experts decanted and tasted it on Friday evening, organisers said.

"I've had shipwreck wines before," master sommelier Paul Roberts said.

"They can be great."

This one, obviously, was not.

To peals of audience laughter, the panel said the cloudy yellow-gray liquid smelled and tasted like a mixture of crab water, gasoline, salt water and vinegar, with hints of citrus and alcohol.

It could have been a Spanish fortified wine, a spirit, or medicine.

But after 151 years at the bottom of the ocean it is now mostly saltwater, they said.

Bouquet of camphor, sulphur and stagnant water

Wine chemist Pierre Louis Teissedre of the University of Bordeaux, who had analysed samples drawn through the cork earlier, said the "nose" of the wine was a room-clearing mix of camphor, stagnant water, hydrocarbons, turpentine and sulphur.

Analysis showed it was 37 per cent alcohol, he said.

The wine was one of five sealed bottles recovered by marine archaeologists from the Mary-Celestia, an iron-hulled sidewheel steamship that sank under mysterious circumstances during the US Civil War.

The boat was leaving Bermuda with supplies for the Confederate states when it struck a reef and sank in six minutes, said Philippe Rouja, a cultural anthropologist and custodian of historic shipwrecks for the Bermudan government.

Whether the sinking was deliberate or accidental has been debated.

Mr Rouja and his brother, Jean-Pierre Rouja, were diving on the shipwreck in 2011 after winter storms swept over the site when they found a bottle of wine inside a secret boatswain's locker in the bow.

Subsequent dives turned up the additional bottles, as well as sealed bottles of perfume, women's shoes, hairbrushes and pearl shell buttons, Mr Rouja said.

This year marks the 150th anniversary of the end of the Civil War, which was fought from 1861 to 1865 and began in Charleston Harbor with the Battle of Fort Sumter.

Reuters