Stephen McGinty: Atlanta's elixir gives the best swig

It's the glass bottle and all that it involves that makes Stephen McGinty go for Coke rather than our other national drink

SINCE my licence to consume alcohol was revoked many years ago, my beverage of choice has been an ice-cold bottle of Coca-Cola. Just as James Bond prefers his Martini shaken, not stirred, so I favour the syrupy elixir of the gods served in the classic glass bottle designed by Earl R Dean in 1915, (for which his company rewarded him with a choice between $500 or a job for life - he took the job), for a Coke somehow tastes better from a glass bottle than a crushable can and, after all, a man does like to swig.

The glass bottle, which is now so iconic, was the result of a deliberate attempt by the Coca-Cola Company to create a unique bottle "which a person could recognise even if they felt it in the dark, and so shaped that, even if broken, a person could tell at a glance what it was." A competition was launched among the firm's suppliers and, at the Root Glass Company at Terre Haute in Indiana, Mr Dean sought inspiration from the picture of a cocoa pod he found in Encyclopedia Britannica. In the original design, the middle of the bottle was wider than the base with the result that it proved unstable on the production line, but once the waist was neatly nipped, it proved a winner.

On 8 May, Coca-Cola will celebrate its 125th birthday, and I, for one, plan to wish them well and hoist a few chilled bottles in celebration. For on that day at Jacob's Pharmacy in Atlanta, Georgia, the first of billions of glasses of the fizzy pop was poured. Coca-Cola had been developed by John Pemberton as a non-alcoholic version of his coca wine which had recently fallen victim to the state's new prohibition laws.

Customers at the time could still enjoy a kick for their 5, considering that the drink's principal ingredients, from which its name is derived were coca(ine) and the caffeine derived from the kola nut. The drink once contained 9mg of cocaine per glass, but this was removed in 1903. When first launched, Coca-Cola was a health drink, part of the then vogue for the health-giving properties of carbonated water, and Mr Pemberton swore by his product's ability to cure headaches, impotence and morphine addiction, from which he himself suffered.

The logo was present from the earliest days as it was created by Frank Mason Robinson, Pemberton's book-keeper who also coined the name and enshrined it in the elegant script known as Spencerian, which was so popular at the time.

The seeds of the global success of Coca-Cola were sown early by the company's grasp of advertising. Pemberton issued coupons redeemable for a glass of his product and by the 1890s used the model Hilda Clark raising a glass with the tagline: "Drink Coca-Cola".

While it is often claimed that the company invented the modern image of Santa Claus, with his red suit, black boots and white beard, during an advertising campaign in the 1930s, they merely projected an image which had been around for decades and used by other drink companies such as White Rock Beverages in 1923.

The company's global reach was helped by its decision to supply Coca-Cola syrup to independent bottlers around the world who produced the drink under licence but at arms length. This allows the company to distance itself from the domestic troubles at international bottling plants, as detailed in Mark Thomas's book Belching Out the Devil: Global Adventures with Coca-Cola. This listed a litany of complaints - that the corporation ignored the murder of union organisers in Columbia, how factories depleted the water level in India and where, in Mexico, bottlers refused to sell the product to bodegas that stocked competing brands.

Yet in Scotland the perception is that Coca-Cola has stiff competition from another drink brued from a secret recipe. Irn Bru is the Joker to Coca-Cola's Batman, the eternal foe with whom he had been locked in mortal combat for decades and without one it is hard to imagine the other, in Scotland at least.

Just as the secret recipe for Coca-Cola is, reportedly, know to only two executives in Atlanta, Georgia (we'll ignore the fact that it has been reproduced in a number of publications), so Robin Barr and one other unnamed executive are reportedly the sole keepers of Irn Bru's secret, with Mr Barr mixing up the formula once a month at its headquarters in Cumbernauld. Just as Coke syrup claims to settle upset stomachs, so Irn Bru is said to calm the rages of a hangover.

While Coca-Cola was born in Atlanta, so Irn Bru was formed 15 years later when, in 1901, the staff at the William Beardmore & Co steel work were looking for a non-alcoholic drink to quench thirsts produced by the heat of the furnace. AG Barr, a local drinks supplier, created Iron Brew but when, in 1946, the licensing laws prohibited any drink that was not fermented from being described as a "brew", the management at Barrs opted to change both names to a phonetic style that reflected the accent of its birth place.

The image of Irn Bru as the Joker is more clearly illustrated by its advertising campaign. Where in the past it was branded as the epitome of Scottishness, associated with the Forth Road Bridge as "Made in Scotland, from Girders", it now relies on humorous, mildly controversial ads. Alex Salmond wrote in The Scotsman five years ago: "Irn Bru's advertising has since gone alternative and Coca-Cola now outsells our national drink in Scotland. They should have kept the original campaign because the Forth Bridge reaches deep into the Scottish psyche; most of the things it touches are strong and positive."

Yet the perception that Irn Bru ever sold more than Coca-Cola has been described as an urban myth. Coca-Cola has always, it appears, been the first choice of Scots and today Diet Coke has sales of 63 million in Scotland, with Coca-Cola at 61m and Irn Bru languishing in third place with sales of 45m according to AC Nielson. Coca-Cola, which has invested 50 million in Scotland over the past 12 years and continues to employ 400 people, principally in East Kilbride, has recently exerted its dominance with a new sponsorship deal with the SECC in Glasgow, Irn Bru's traditional heartland.

So why do I favour the American import over our other national drink? Perhaps it's the iconography, the cultural heritage, the notion that, as Andy Warhol once said, Coca-Cola is uniquely democratic in that the bum on the street and the President of the United States enjoy the same taste. There is no such thing as a vintage Coke. But it's the rigmarole of hauling out the bottle opener, cracking off the bottle top, listening to the symphony of escaping gas and taking that first burning glug.

Then there are the stories, my favourite of which is of Marshall Zhukov, the Soviet saviour of Leningrad, who developed a taste for America's imperialist pop while negotiating with Eisenhower in post-war Berlin, but was prohibited from enjoying supplies upon his return, so the executives of Coca-Cola developed a colourless version, which was sent to him in a specially designed bottle marked with a Soviet red star.