The country's oldest stout brewery, Beamish and Crawford in Cork, will fully shut down by the end of May.
Its new owner Heineken confirmed that it had been due to shut the plant today but logistical problems have delayed the closure.
80 of the 160 workforce have already been made redundant. 40 others have transferred to Heineken's Cork headquarters, while the remaining 40 workers will oversee the fermentation and bottling of the final beer product at the historic South Main Street plant.
Heineken has also confirmed that it intends to sell the four-acre site in the heart of the old city of Cork, once decommissioning of the plant is complete. This process could take up to eighteen months.
According to Corporate Affairs Manager Declan Farmer, Heineken is not in the business of developing property, and while the company is aware of both the historic and heritage value of the site, once a sale is agreed, his company's involvement in the site will cease.
Historians say there has been a brewery on the site since the mid-1600s. Beamish is the oldest porter in the country.
Heritage campaigners are concerned about the future of the site and its famous Tudor counting house, whose frontage is preserved.
The National Conservation and Heritage Group, which persuaded Guinness to develop the Guinness Storehouse in Dublin, say they will take their campaign to save the site to the streets, if the multi-national brewer does not 'engage with them in a meaningful way'.
They want the company to develop a micro brewery style tourist attraction at the historic site.
Earlier this week, Heineken confirmed that Beamish will no longer be sold anywhere outside Ireland. The company says it is to focus on selling it in the Irish market north and south.
