Wolverhampton & Dudley Breweries (W&DB) has defended its record on cask ale as the deal to buy Jennings draws closer.
Jennings shareholders have an initial deadline of May 19 to decide whether to accept W&DB's £45.8m takeover bid.
However, there has been widespread concern that the Jennings brewery at Cockermouth in Cumbria is not safe.
Critics cite the example of the Mansfield brewery which W&DB purchased in 1999 - and closed only two years later.
However, Alistair Darby (pictured), managing director of W&DB Brands, said the Jennings brewery was not in danger. "The Jennings brands and brewery will be just as protected under our stewardship," he said.
"Obviously the closure of Mansfield upset our customers. But those same customers all agree that the Mansfield beers we produce are still bloody good."
However, Jonathan Mail, public affairs manager for the Campaign for Real Ale (CAMRA), said: "The best way to ensure the future of the brewery is for Jennings to remain independent."
CAMRA has set up a petition at www.camra.org.uk.