Peter Ross: Raise a glass to Old Stoatwobbler and Sheepshaggers Gold

TWO o'clock on Wednesday afternoon and the Paisley Beer Festival is frothing with excitement. Judging for the Beer Of the Year award has entered its climactic stage. This morning the judges sampled 48 Scottish ales and have narrowed it down to 12. The winner used to be settled by public vote, but breweries were rigging it. "Let me get a beer, will you?" says Danny Matheson, the festival organiser and my guide for the day. "I feel naked without one."

He has plenty to choose from. Based in Paisley Town Hall, a giant Victorian building looming suicidally over a canal, this is Scotland's biggest beer festival, serving 14,000 pints in four days. Punters can sample more than 150 different real ales, including Old Growler, Old Stoatwobbler and the improbably named Sheepshaggers Gold, a brew which makes up in maltiness what it lacks in possessive apostrophes.

The six judges seated around a table near the stage in the grand central hall are not, for the most part, the same judges who were testing beer this morning. Those people will have drunk up to seven pints in two hours and by this point are probably unable to taste the difference between macaroni and macaroon. What's needed now is a clear head and sensitivity to flavour. There is a lot at stake. The winner today will go on to compete for the Champion Beer of Britain trophy. Brewers stand around nervously watching the judges sip and swill. Beer is brought to the table in unmarked plastic containers identified only by a letter and number. I suspect, though, that the brewers know their product well enough to recognise it from a distance. They can doubtless spot a pint of Hanged Monk at 20 paces.

Lisa McBryde, 41, has short dark hair and an accent that daunders between her native Philadelphia and her adopted Scotland. She is the sole woman on the judging panel, and has worked here since 1988.

There's a widely held belief that women and real ale do not mix – "you stick to the sweet sherry, love" – but the Renfrewshire branch of the Campaign For Real Ale is more or less a matriarchy. The chair, vice-chair and secretary are all women. The deputy in charge of the Scottish beer bar is called Bunty, which is about as far as you get from the whiskers and pipe cliché.

I'm told that half of the 3,000 punters attending the festival are women. Maybe so, but it's mostly men I see flooding in the door. These are divided into three physical types: men so stout they look as though some cosmic barman poured them into their skins and left the tap running; men combining Rapunzel hair with Rasputin beards; and men with noses so florid they could guide a sleigh through a snowstorm. There is also a tendency to eccentric dress. One man wears a black kilt decorated with an anarchy symbol, another sports the sort of gold cowboy hat that Madonna might put on to ride a mechanical bull.

McBryde explains that she and her fellow judges assess the beers on four criteria – clarity, aroma, taste and aftertaste. This last category is the reason beer buffs, unlike wine connoisseurs, don't spit after tasting. Between beers, the judges sip water and nibble crackers to cleanse their palates.

Each new beer is poured into a fresh glass. The judges shine torches into the liquid, looking for signs of cloudiness or worse. "I used to drink milds, which are so dark you can't see through the glass," Matheson says. "Once, I got down to the last third of a pint, tipped my glass up, and there was a slug at the bottom."

Urgh, was he sick? Matheson looks shocked at the question. "Aw no," he says. "That would have been a waste of beer."

He is a wee guy of 45 with a prow-like belly that bears witness to many voyages to the pub. A prison officer and taxi driver, he has organised the festival for five years and this will be his last hurrah. Every year it gets harder, thanks to health and safety regulations and increasing insurance premiums. Plus, there are always unforeseen rocks on which to run aground.

The present crisis is that all the cider – 128 gallons of the stuff – has been lost in transit. A simple case of damage en route, says the haulage firm, but Matheson suspects foul play. The scrumpy has been scrumped, and so he has spent the morning arranging couriers to pick up fresh supplies.

Happily, the casks of English ale arrived on Monday and have been left to settle. The foreign beers are in another room. These are the province of Bob Raine, a gentleman in his forties whose hair and beard bring to mind the late Charlton Heston as Moses.

Raine has toured Europe and beyond in search of the best beers and is presenting 54 of his favourites, including the fearsome Belzebuth, from France's Jeanne d'Arc brewery, which is 13% proof. Surely you can't drink many of them of an evening? "Well," Raine smiles wryly. "Folk try."

The foreign beer bar is the brightest part of the festival, decorated with flags of nations from which Raine has sourced booze over the years. As the festival has been going since before the fall of European communism, this includes a prominent Soviet standard. Paisley is not only a good place to get hammered; you can get sickled too.

America's stars and stripes is tucked down the side of the bar, almost completely out of sight. This, explains Raine, is a "political statement" designed to wind up McBryde. "She says, 'Nothing can hang higher than Old Glory,' and that's a red rag to a bull, so everything hangs higher than it. She moans every year, and every year Old Glory gets lower down and further away."

Back at the judging, the last few beers are being sampled, and soon the winner is announced – Red Macgregor, made in Quoyloo, an Orkney village beloved of beer-and Scrabble fans. Once the trophy is handed over, it's time for me to go. After hours at the festival, I'm starving, but sadly, the German sausage stall hasn't opened. The wurst, it seems, is yet to come.