Added: Thursday, December 1st 2011
Marston's will launch Fast Cask during Cask Ale Week (29 March-5 April) with the aim of attracting thousands of new pubs to real beer.
Fast Cask involves a form of yeast treatment that allows beer to drop bright quickly while still undergoing a secondary fermentation. The system is the brainchild of Richard Westwood, Marston's director of brewing. He was asked to tackle the problem that cask beer is not available in 46% of pubs and bars in Britain as a result of a lack of cellars or the misplaced belief that real ale is difficult to look after and serve.
Fast Cask, which will initially be used for Marston's Pedigree and Wychwood Hobgoblin, involves removing yeast at the end of primary fermentation and replacing it with "beads" of fresh yeast.
The beads are produced by a process in which fresh yeast solidifies into small beads that act like tiny sponges. The sugars in the beer diffuse into the beads and a secondary fermentation takes place. Marston's is not yet prepared to reveal the process used to produce the beads as patents are pending.
As the beer drops bright almost immediately, it can be served from upright casks that can be moved around at will. In a demonstration at Banks's Brewery in Wolverhampton, Richard Westwood produced two samples of beer in tall glass laboratory cylinders. One contained traditional yeast cells, the second the new beads.
When he agitated the cylinders, the traditional yeast remained in suspension while the beads immediately dropped to the bottom of its cylinder.
Stephen Oliver (right), who runs Marston's Beer Company, said the system would eradicate the age-old problem of casks being knocked in small, crowded pub cellars followed by a delay of several hours until the beer dropped bright again.
While casks using the system can be stillaged in the usual horizontal manner in pub cellars, they can also be stored upright if no cellar exists and the beer has to be kept in small spaces at bar level.
Both Oliver and Westwood were at pains to stress that casks will still have to be tapped and vented to allow them to breathe. But Fast Cask will enable real ale to become available to many more pubs and also to such outlets as trains and cruise ships.
They also pointed out that pubs serving Marston's cask beers in the traditional manner will continue to be supplied with beer that contains normal yeast cells.
Richard Westwood said the beads were similar to tea bags. Extensive trials in Marston's laboratories have measured secondary fermentation using the beads. It was found that the amount of yeast within the beads is within the range usually found in cask beers but the beads give a more consistent secondary fermentation due to the precise amount of yeast that is added.
Fast Cask has undergone trials in 70 pubs since November 2009 and there has been no adverse consumer reaction. Marston's will seek a patent for the yeast beads but it will consider sharing the technology with other brewers in the future.
One advantage of Fast Cask is that finings made from fish bladders will not be needed to clear the beer and as a result real ale will be acceptable to vegans.
* As of 15 March 2010 The Campaign for Real Ale has yet to approve Fast Cask. Members of CAMRA's Technical Advisory Group are due to meet Richard Westwood on 27 March to discuss and analyse the system. ends