The latest round of whinging on about CAMRA in the world of internet beer nerdery lead me to post a fundamentalist rant of my own. Slightly surprisingly one of the comments my rant received was asking a serious question so I thought I'd better do a more serious post.
Jason Stevenson of Lovibonds brewery asked "Why do you assume that because beer is in a keg it somehow has to be filtered or pasteurised?". Elsewhere Jeff Rosenmeier of Lovibond's has said that it is a myth perpetuated by CAMRA that keg beer is filtered and pasteruised.
Now at the simplest level kegs are cylinder shaped draught beer containers. In theory they could be filled with whatever you like, you could fill them with engine oil if you wanted to. Sticking with beer though, according to Lewis and Young in the standard industry text book Brewing: "A major change in brewing technology was the filtration and pasteurization of the beer in the brewery and packaging under pressure of carbon dioxide into metal kegs."
CAMRA was formed in reaction against this change to keg beer, and in defence of unfiltered and unpasteruised cask beer or real ale as they define it.
People from Lovibond's have said that they neither filter or pasteruise their keg beers, but this is not what kegs were designed for and must surely be a rarity. Even if other breweries apart from Lovibonds make unfiltered and unpasteruised keg beer I'd be very surprised if production topped 10,000 barrels a year.
Over 13 million barrels of keg beer are sold in the UK each year, so according to my estimate over 99.9% of keg beer in the UK is filtered. So that's why I assume keg beer is filtered or pasteurised, not because of some CAMRA myth, but because 999 times out of a 1000 I'd be right.