The travellers eventually moved out on May 28 but not before windows were smashed, walls were vandalised, doors were ripped off their hinges and rubbish was left strewn around the building in Penny Street.
On Tuesday, police carried out dawn raids at a traveller camp on Leverhulme Park in Bolton.
Detectives are questioning a 43-year-old man on suspicion of burglary and blackmail, a 32-year-old man on suspicion of burglary, a 33-year-old man on suspicion of burglary and shoplifting, two men aged 21 on suspicion of burglary and a 16-year-old boy on suspicion of burglary.
Assistant Chief Constable Jo Edwards, of Lancashire Police said: "The incidents at Thwaites over the Bank Holiday weekend understandably caused a huge amount of upset and anger in the local community and we recognise that.
"We have had a dedicated team of officers working hard behind the scenes to identify those responsible for causing these unacceptable criminal acts and this morning's activity is just the latest stage in our ongoing investigation.
"We continue to work closely with Thwaites Brewery and we have updated them with this morning's activity."
"I would like to remind people that we generally have good relationships with the travelling community and the level of destruction and damage caused to the Thwaites site is not reflective of the behaviour of the majority of travellers."
Earlier this month Thwaites confirmed it was unable to continue its 211 years of brewing beer at Penny Street because of the damage inflicted which cost more than £100,000.
Production will resume later this year when the brewery completes its planned switch to new headquarters in nearby Mellor Brook.