Molson Coors plans to spend up to $500 million to build a new Montreal brewery instead of modernizing its 231-year-old facility along the St. Lawrence River.

The brewer's decision, which follows a two-year study, was announced to employees on Wednesday.

The location of the new brewery hasn't been determined yet, said Molson Coors spokesperson Francois Lefebvre.

"It's too early to determine where the new brewery will be," he said. "What we're doing right now, we started a business plan to determine where the best location for us will be. We're talking about the size and location of the new brewery and what we're going to do with our heritage site here."

Molson Coors Canada CEO Fred Landtmeters says building the new brewery will be more efficient than updating the existing operations.

The brewer plans to maintain a microbrewery and sales venue at the historic site near Old Montreal, with the rest being sold for redevelopment under the auspices of the city.

"We want to make sure we're keeping a legacy for Montreal and for Quebec here on Notre-Dame St," said Lefebvre.

Molson Coors employs approximately 1,000 people in Montreal between its Notre-Dame St. brewery and its Dickson St. distribution centre. Eric Picotte, president of the union representing Molson Coors workers, said the announcement is good news, as it promises to keep jobs in Montreal. However, 

"We have a big concern about what kind of production is going to be made in this new factory. If Molson makes all the production in cans instead of bottles, it's going to result in a big decrease in the number of employees. Our bottle line needs 16 workers per shift in each line to produce the beer. Our can line only needs four workers per shift for each line."

He added that in the five years since cans of beer began being made at the Notre Dame facility, 100 jobs have been eliminated as more and more production space was dedicated to the cans. More than half of the products now made at the factory are in cans, he said. 

Lefebvre said that while plans are still in the preliminary stages for the new facility, both canned and bottled products will be made there. 

Molson Coors sold its operations in Vancouver last year. The company will continue to produce beer at that site for up to five years while it builds a new facility in Chilliwack, B.C.