On 22 September, the world's most famous beer festival begins in Munich. But just as there is a misconception about when Oktoberfest starts - September, confusingly - so, too, there is one about its status as a beer pilgrimage. In truth, it's a Bavarian knees-up beloved by tourists and devoted to established brands. You can't wander around and sample; instead, the visitor must choose a tent belonging to one of the city's big-name brewers, sit down at a table and drink the same thing all night.
Britain's equivalent comes far closer to being a real beerfest, although it, too, is built on a glaring contradiction. Every year in August, tens of thousands of people converge on a huge, soulless hangar in central London in search of the rich cosmos that is Britain's local brewing industry - an abundance of bitter, mild and stout with names like Shropshire Lass, Pit Shaft, Golden Lance and Roaring Meg. Each beer has been uprooted from its natural ecosystem, lugged hundreds of miles in a lorry to central London and served up in a building with all the ambience of a bus depot in Ceausescu's Romania.
It's about as far from the fireside pint at the local as one can get, but people love it. Set up by the Campaign for Real Ale (CAMRA) in 1977, the Great British Beer Festival has become one of the capital's summer highlights since it moved to Olympia in 1992, and last year to the even more cavernous Earls Court, attracting 66,000 people over the five days. That's still only a hundredth of the attendance of the 17-day Oktoberfest, but not bad for a tipple that not so long ago was being read the last rites by drinks-industry analysts.
I'm a son of Burton-on-Trent, so really it's my solemn duty to go along. Real ale is special because it uses traditional ingredients that are left to mature in the cask through a process called secondary fermentation, which is what lends it its rich, complex flavours. So there I was again, on the opening day of the 30th festival, being issued with a pint glass and wondering which of the 700 brews to start with. I found myself at the stand labelled Central Southern England - CAMRA does love its confusing subregions - and began with a third of Moleton Silver from the Moles Brewery in Wiltshire.
Crudely speaking, my fellow drinkers could be split into three distinct groups - the demob-happy, after-work crowd in suits and shirtsleeves, the hardcore real-ale fans with the standard-issue paunch and facial hair, and last the tourists, delighted by what they had stumbled upon. It's usually a wider mix of ages than you get in most bars or pubs, and in ethnic terms there seem to be a lot of Chinese and Japanese drinkers, although real ale doesn't seem to have made many inroads with black Britons. But before the government starts drawing up proposals for an access regulator, it is worth pointing out that the festival's appeal is evolving organically. Although eight out of ten women have never tried real ale in the pub, there is a growing number of female enthusiasts and perhaps a third of drinkers in the hall were women.
This year CAMRA introduced the third of a pint measure to maximise one's opportunity to sample. And that is the event's charm: once you've paid your £8 to get in, you can, rather like an adult Charlie in the chocolate factory, explore every region of Britain at sub-London bar prices. The real fun comes in comparing notes with your fellow drinkers. My party variously decided that Burton Bridge's Golden Delicious was "seaweedy", Skinner's Betty Stogs Bitter was "sau sagey", 1648's Lammas Ale "would be good with chocolate cake" and Bushy's Pure Gold from the Isle of Man was "sessionable".
The picture one gets is of a brewing industry in rude health. But away from this one-off extravaganza, cask ale accounts for only 7 per cent of beer sales in the UK, with 55 per cent of all beer being sold at supermarkets and off-licences. The big four brewers - Scottish & Newcastle, Coors, InBev and Carlsberg - are global brands with more than 80 per cent of the domestic market that have ditched bitters to concentrate on buying up the world's most lucrative lager brands. Real ale is an irrelevance to them. But their lack of interest has left room for the larger regional brewers such as Marston's, Greene King and Fuller's, and beneath them hundreds of micobreweries.
Real-ale fans have mixed feelings about the medium-sized players. On the one hand they are serious about selling cask ale and investing in their breweries. On the other, they are predators, buying up the small and interesting and, in the case of Greene King, closing them down, moving production to their own Bury St Edmunds HQ, and forcing newly acquired pubs to replace local favourites with their own beers. The microbrewers are what the Great British Beer Festival is really about and on this score there are grounds for hope. They may account for only 2 per cent of the market overall, but they seem to be on a roll, aided by the trend for local food and drink.
It's not just about taste. Drinking beer produced by a local business five or ten miles down the road rather than shipped from the other end of the country seems sensible: "sustainable", if we must. And the thousands of vertical drinkers at Earls Court demonstrated another virtue - handling their booze. Without academic research into this murky area one can only speculate: is it the real-ale drinker's nature or the qualities of the drink itself that make its effects more good-humoured than the belligerent feeling lager drinkers get? A bit of both, I suspect. Perhaps officials at the Treasury should look into the practicability of bringing in a variegated duty for beer, with real ale benefiting from lower rates than "antisocial" lager.
The champion beer this year was a Shropshire brew called Hobsons Mild. But for me Butcombe Bitter from Wrington in Somerset won the day. The whole process is subjective, of course - not only do I like its nutty bitterness, but there's the fact that I discovered it some years ago in a pub in Pilton before a rain-sodden Glastonbury Festival. In beer, geography, memory and taste are all intricately linked, which is why our local breweries are so important to the country's heritage. The Great British Beer Festival brings this diversity together and inspires you afresh, so that in the end the contradiction of paying homage to a local craft in a big shed in Earls Court dissolves into your glass with the hops and barley.