When CAMRA was formed in the early 1970s, it settled upon the definition of “real ale” as involving the beer undergoing a secondary fermentation in the container from which it was served. For most British cask beers at the time, that was the case but, taking a wider historical perspective, might it have been more of an aberration than a universal principle?
A commenter on one of the beer blogs (I think it was Tandleman’s) recently said that, going back 60 years, pretty much all draught beer in the world was cask. But, apart from the British Isles and some isolated pockets in other countries, by that time virtually all of the world had adopted the bottom-fermenting lager technique for making everyday beers. This involves a period of cold-conditioning in tanks or barrels, during which time the beer will stabilise and drop bright. By the time it is released for sale, it is no longer experiencing any kind of fermentation. It may be unpasteurised, served using its own CO2, cloudy even, but it’s inert. The same is true of German top-fermenting styles such as Alt and Kölsch.
Even if we look at British top-fermenting beers, it has been by no means always the case that they were served by the current “cask-conditioned” method. Historically, many beers, notably porters, were matured for long periods in vats, during which time, as with lagers, they would have stabilised prior to barrelling and despatch to pubs. A famous example of this was the 1814 London Beer Flood. And all that IPA sent out to India didn’t continue working away during the three-month voyage. It effectively became a barrel-aged beer that was preserved by being kept in airtight casks.
In more recent times, Martyn Cornell in his excellent book Amber, Gold and Black points out that most mild was sent out from the brewery with a minimal or zero amount of yeast with the intention of being served within a few days. It was effectively “re-racked” beer. The presence of significant secondary fermentation was the feature that distinguished bitters from milds. This is why slops were put back in the mild, as they would stir up the yeast in the bitter.
While undoubtedly in 1970 cask-conditioned British bitters experienced a significant secondary fermentation, they were pretty much the only draught beers in the world that did. And that doesn’t even venture into the territory of bottled beers.
So a test of “good beer” that could be applied more widely in other countries with different brewing and beer-drinking traditions might have focused more on the absence of pasteurisation and the non-addition of extraneous CO2, allowing beers to settle out naturally or only being rough-filtered and, yes, the quality of ingredients.