Job cuts would come from the brewing and tanking room, packaging, warehousing, planning, engineering and management teams.
In total 83 workers will be involved in the “consultation process” with plans to restructure the business, leaving just 58 jobs.
The proposed restructure will see Thwaites move from a three and two shift operation to a single, extended 12-hour shift.
The brewery said the move is “in response to the loss of a number of packaging contracts and increased customer pressure to reduce costs”.
It would mean Thwaites ends contract packaging, aside from a small number of legacy agreements which will run the course of their contract.
Elsewhere in the business there are proposals to cut the customer administration and reception teams by two members of staff.
Thwaites has said it hopes to minimise job losses through “redeployment and a voluntary redundancy programme” and is offering all affected staff a series of “outplacement sessions”.
Managing director Steve Magnall: “It’s obviously a very difficult and upsetting time but this is very much about getting us fit for the future and having the right size and scope of team for the new brewery which will be a significant milestone in the history of our strong and successful company.”
Chief executive Rick Bailey added: “These are incredibly tough times for all businesses and most companies in our sector and elsewhere are focusing on ways that they can save costs and work more efficiently, unfortunately this also includes considering job losses, which is the hardest decision to make.
“It is imperative that we continue to adapt our business to reflect changes in the market and remain competitive whilst not compromising on the quality of the beers that we brew for our customers.”