Jennings Brewery was established 1828 in the village of Lorton, between Keswick and Cockermouth. The brewery was started by John Jennings. Jennings moved to its present home, the Castle Brewery in Cockermouth, at the confluence of the Rivers Cocker and Derwent in 1874.
Jennings Brewery brew a range of ales using lakeland water drawn from the brewery's own well, malted Maris Otter barley from Norfolk and Goldings, Fuggles and Challenger hops from Kent, Herefordshire and Worcestershire. The malt used by Jennings brewery is screened and crushed rather than ground into a flour to keep the husks as whole as possible. The hops used are flaked rather than the increasingly popular hop pellets available nowadays.
In May 2005 Jennings Brewery was purchased by the national brewer, Wolverhampton & Dudley Breweries, renamed Marston's PLC in January 2007. The purchase was opposed by the Campaign for Real Ale, which feared W&DB would close the Cockermouth brewery. These fears seem to have been unfounded, however, as in June 2005 W&DB announced it would invest £250,000 to expand fermenting and cask racking capacity in Cockermouth, this work had been completed before the end of October 2008
Following the takeover by W&DB, the brewery's distribution centre in Workington was closed and its tied estate of 127 pubs absorbed by the W&DB pub company. Due to the takeover and subsequent name change, Marston's Pedigree is becoming more common in Jennings pubs.