Beer festivals spring up and die as fast as hops. The enduring success of Frocester's is due almost entirely to the enthusiasm and skilful organisation of its founder, Dennis Haddrell, whose family ran a wood-turning business in Dursley.
In 1979, along with a fellow member of Stroud Lions Club, he started looking for a site out in the countryside, equipped with electricity but away from dwellings, and he approached the cricketers of Frocester with the idea of holding a festival on a triangular piece of ground behind their pavilion. Profits (or losses) would be shared fifty-fifty.
His idea was simple enough: to lay on a large variety of brews from different parts of the country, and let customers loose on them amid basic amenities. The festival soon became amazingly popular. In 1982 - the first year for which figures survive - the organisers sold 1,800 tickets at pounds 1.50 each before the day and pounds 2 on the gate. Last year 5,000 tickets at pounds 5 apiece were snapped up a month in advance, and this year they went just as fast. In 1982, 7,000 pints of beer, cider and perry went down the hatch; in 1998 consumption passed 27,600 pints, along with 574 bottles of wine.
Since there are only two sessions - Friday, 6pm to 11pm, and Saturday, 11 am to 11pm - and a total of 17 hours' drinking time, it is easy to calculate that the pints must go down at the rate of about 1,800 an hour, or 30 a minute.
Most of the customers naturally come from the surrounding Stroud valleys, but a good number are from farther afield. Some of them hold university reunions on the site, some wear Viking-type horns, and others, such as the Costa Frocester gang, buy special rugby shirts for the occasion.
Over two decades arrangements have scarcely changed. On arrival each ticket-holder is given a pint mug or a wine glass, which is his or hers to keep (the clientele is thought to be about 60 per cent male and 40 per cent female). The punters then buy strips of vouchers which they can exchange for drink or food. Music is provided by bands playing in an open- fronted, 40-ft trailer, and there is plenty of solid fare to soak up the ale; last year the crowd got through 28 whole pigs and 700 beefburgers, besides a mountain of sandwiches.
The main attraction at the festival, though, is the beer. This year there will be exactly 100 brands on offer. The barrels are ranged on steel racks down the back of a long, open-fronted marquee, and the bar itself is deliberately made minimal - the steel rail is so uncomfortable to lean on that it encourages customers to move off quickly, as soon as they have bought their pints.
Pride of place goes to the local Uley Brewery, in recognition of the help that its proprietor, Chas Wright, has always given to the festival. He alone is provided with a proper wooden bar, reinforced with angled scaffolding poles to withstand the pressure late on Saturday night when, with other brews running out, connoisseurs throng the pitch six and eight deep, rooting for his Old Spot and Pig's Ear ales.
The most remarkable feature of the festival is its cheerful atmosphere. With plenty of 20-pint men on site, you would expect violence to erupt fairly often.
In fact fights are almost unknown, and if one does break out, it is instantly quelled by the security team who throw brawlers into, or through, the hedge. Camping and caravan space is provided for those too far gone to travel, and taxis can be laid on to cart off the incapable.
Another strange fact is that the weather seems to make little difference to the success of the event. The throng of boozers is too large for everyone to squeeze into the marquee, so if it rains, hundreds are left jumping up and down in the open.
Nobody seems to mind - and indeed, one year when the heavens really opened, some of the wilder spirits took the opportunity to embark on a bit of mud-wrestling in the centre of the arena.
In Dennis Haddrell's view, the festival succeeds because the setting is exactly the right size. "Some people have said we should move to a bigger site," he says, "but then we'd lose the atmosphere." To Chas Wright, the point is that "there's no feeling of menace, and no one's trying to prove anything. Everyone can get happily pissed without any aggravation."
The cost of putting on the festival has rocketed, but so have the profits - to more than pounds 40,000. Last year pounds 5,000 apiece was given to playground appeals in Frocester and the nearby village of Leonard Stanley. The cricket club and the Lions shared the remainder - and of their pounds 15,000 the Lions gave pounds 2,000 to the North Nibley church bells appeal, pounds 2,000 to the Dursley day centre, pounds 2,000 to the Cotswold Care Hospice, pounds 3,000 to the Willow Trust (canal trips for the disabled), pounds 3,000 to Rednock School for a summer literacy scheme for backward children, and pounds 2,000 to the Severn Auxiliary Rescue Foundation.
It seems only fair that over the years the festival has made a substantial contribution to the fortunes of Frocester Cricket Club, one of the most successful village clubs in the area, which fields one junior and three senior teams. So far this season none of the senior sides has lost a match; the first and third have already won their leagues, and the second looks likely to do the same.
Still better, secure finances recently enabled the club to acquire a second playing field, mainly for the benefit of junior players. To buy six acres, re-seed them, lay a square and build a new pavilion cost more than pounds 50,000, and although a handsome slice came in the form of a lottery grant, much of the rest was down to sales of beer.
The festival, in other words, has become a major benefactor in the area. On Friday morning, to make sure that standards do not drop, Dennis will taste every brew on offer - Gaol Ale, Stairway to Heaven, Tanglefoot, Skullsplitter, Bitter & Twisted, Utter Nutter and Whistlebelly Vengeance among them.
He'll send away anything that's "off" - but there is one beer that he definitely won't be criticising, and that is the Old Dennis Ale, specially created by Mel Griffiths, the head brewer at Uley, for the 20th anniversary of the festival and the 70th birthday of its founder.