Rock 'n' roll is synonymous with excess, and alcohol-fuelled antics have often put the fizz into showbiz. Rock music has always enjoyed a shaky relationship with the demon drink, but in recent years the marriage has become rock steady, thanks to increasing support from major drinks companies and breweries.

The once-flagging Irish music industry is now being propped up by sponsorship from such brands as Heineken, Budweiser, Bacardi, Guinness and Carlsberg, all of which are eager to target the young, trendy drinkers. Thanks to events such as the Heineken Green Energy Festival, the Bud Thud, the Guinness Blues Festival, and the Carlsberg Kilkenny Roots and Country Festival, Irish rock and alcohol now enjoy a respectable relationship.

It might be intemperate to say there would be no Irish music industry without sponsored support from drinks companies, but it would not be far from the truth.

Next weekend, the capital's biggest yearly music event, The Heineken Green Energy Festival, will bring some of Britain's top bands to play in the grounds of Dublin Castle, including UB40, The Beautiful South and Catatonia, plus numerous other acts such as The Happy Mondays, Jewel, Faithless and Mercury Rev in other venues around town.

Now in its fourth year, the festival has become a sort of convention, bringing music industry people from around the world into Dublin for the May Bank Holiday weekend.

Every concert, seminar and club event of the weekend will be lit up by a galaxy of red stars, the trademark of Heineken. As the crowds rock to The Cardigans, dance to Mani from The Stone Roses, and discuss burning musical topics with Boyzone manager Louis Walsh, they will be constantly reminded just who is underwriting this shebang. Pints of Heineken will be pulled at the Castle, while pubs will display the red star prominently about their premises.

Meanwhile, in Galway, Budweiser will be leading young drinkers on a merry May Day dance in the company of top DJs Goldie, David Holmes and Talvin Singh, at the second annual Bud Thud. Further south, in Cork, is the Guinness Roots & Reggae Festival, hoping to add some froth and sunshine to the Bank Holiday and in the south-east, Carlsberg is the sponsor for the Kilkenny Roots & Country Festival.

Without these high-profile events the May Bank Holiday would be a dull affair. But are drinks companies the saviours of Irish rock, or has the music industry become too drink-dependent?

The argument in favour of drink is that sponsorship is needed to nurture rock and aid in its future development. Heineken makes much of its "grassroots" involvement in Irish rock, through such events as the Heineken Rollercoaster Tour, which brings young Irish bands to audiences around the State, and the Heineken Demo Marathon, in which young hopefuls get advice and encouragement from a panel of music industry professionals.

The Bacardi Unplugged Competition is another grassroots event, designed to give a hand up to young Irish bands. The competition has been running for five years; when it started, the prize fund was around £6,000 (€7,620). At this year's final in the HQ on Abbey Street on May 14th, the winning band from an entry list of 400 will walk away with around £20,000 worth of equipment, studio time, and CD production services.

Bacardi Unplugged is also designed to tap into the company's target market of young drinkers, what Bacardi's brand manager Ms Katrina Sheridan refers to as "the recruitment market".

Although the Unplugged competition is Bacardi's biggest sponsorship project, the company also plays on its Cuban origins by giving ad hoc support to salsa and carnival events. This year it sponsored the Cuban music band in the St Patrick's Day parade, and it regularly backs gigs by such Cuban groups as Sierra Maestra and Havana Che.

None of the drinks companies will divulge the exact amount of money spent on sponsorship, but all admit that it accounts for a "significant" percentage of their marketing budget. Murphy Brewery (Ireland), which markets the Heineken brand, is the most highprofile music sponsor in the field, spending more than £2 million a year on such events as the Heineken Green Energy Festival, the Heineken Band Challenge and the Heineken Weekenders.

"Music and drinking go together in Ireland," says Ms Jo Kramers, marketing manager at Murphy's and director of the Heineken Green Energy Festival.

"For most young people aged 18-24, their main activities happen in pubs, clubs and music venues. Since I came to Ireland, I've been amazed to see how central music is to young people's lives. Our target market is harder to reach through standard media such as television, so we reach them through music sponsorship. We want to be associated with successful music events, because that will maximise our brand's exposure, but we also have to treat our consumers with respect, and give them what they want in a credible way."

It is easy to identify a target market, but it is harder to quantify the tangible benefits to the drinks company for its involvement. "We continually monitor our brand health in the market," says Bacardi's Ms Sheridan. "We can quantify things like how much press exposure we get for the Unplugged competition, and the size of the crowd which comes to the various heats around the country. There are three essential requirements for good sponsorship: it must be the right idea, the sponsor must be single-minded in its support, and it must give a long-term commitment, because the benefits will only accrue in the long term.

"I suppose the Irish music industry could survive without sponsorship, but it would be a very different industry. For one thing, there would be fewer niche acts coming into the country - only the commercially-viable blockbuster acts would be able to visit. For instance, we brought Nick Cave in to play for a select audience in the Guinness Hop Store recently, which wouldn't have been possible without sponsorship."

Ms Grainne Wafer, brand PR manager with Budweiser, says that the Bud Thud's success will be measured by the number of people who travel to Galway for this weekend's event, regardless of what they drink.

"Besides the main events, we also have a Budweiser Pub Trail which takes in 15 different pubs around Galway. The typical Bud drinker is aged between 20 and 25 and interested in dance music, so we would expect a good attendance this weekend. Budweiser will get maximum exposure around the city, and after the weekend has ended, we can evaluate its success and see how people feel about the brand."