Kyle Cooper, 20, and Callum Lawson, 21, knew the bizarre event was going to happen due to its inclusion in the programme of the Spirit of Speyside Whisky Festival but were unable to escape their workmates.
The ritual for the two apprentices at Speyside Cooperage in Craigellachie, Moray, acts as a coming-of-age ceremony dating back to the 14th century and usually happens when an apprentice completes their four years of training.
The apprentice coopers, who make and repair casks for the whisky industry, were hard at work when they were suddenly seized by their workmates.
Warning - Adult language is used, viewer discretion is advised
After a futile escape attempt, they were stripped down to their underwear buckets filled with black sludge were thrown and smeared over them.
The pair were then covered in feathers and flour before being put in the last casks they had completed as apprentices, and rolled across the factory floor, while their family and friends - as well as some members of the public who were lucky enough to get tickets - watched from the safety of the viewing gantry above.
Flour and treacle was again thrown over the pair just to ensure the completion of the ritual and the boys were then given a dram of the Cooperage's own whisky, which has been specially bottled for them by a Speyside distillery, the identity of which is a closely guarded secret.
After cleaning himself up, Kyle, from Keith, Moray, explained that the boys knew the ritual was set to happen but that they didn't know exactly when, he said: "It has been coming for a while. I tried to get away from them but I just couldn't."
Andrew Russell, general manager of the factory, helped plan the ritual for the apprentices. He said: "We tried to keep it quiet but they knew something was happening.
"They are both good-natured guys so they have taken it in good humour."
Gill Reid, the cooperage's visitor centre manager, explained the history of the bizarre ritual. She said: "It dates back to the 14th century, back then it was called trussing the cooper, but now it is called a blackening.
"It's a bit watered down from what it was before.
"It's bad enough now but back then they probably wouldn't know some of the things that they were being covered in."
The Blackening was included in the Festival's programme and was voted best new event at the closing ceremony.