LONDON (Reuters) - Brewers face an uphill struggle to persuade more drinkers to buy their beer in plastic bottles, according to a new report.

Drinkers prefer glass because it embodies craftsmanship and quality and represents ``phallic hardness vs the feminine suppleness of plastic,'' a survey by Brand Futures Group, a unit of advertising agency Young & Rubicam (NYSE:YNR - news) which tracks consumer and lifestyle trends, said on Thursday.

Top U.S. brewers Anheuser-Busch (NYSE:BUD - news) and Miller Brewing Co. (NYSE:MO - news) have tested the mass market for plastic-bottled beer, especially among younger consumers, and many companies, including Dutch-based Heineken , already offer niche products in plastic containers.

Plastics experts say they have developed unbreakable bottles which are seven times lighter than glass, offer better flavour and have a six-month shelf life.

But environmental groups are worried that new generation plastics designed to make bottles air-tight cannot be recycled as easily as conventional materials.

The Brand Futures survey said many respondents felt plastic-bottled beer would be good for sporting events, concerts and the beach, but it would ``in the context of social drinking, communicate a lack of taste and refinement.''

``Others said they'd never buy beer in plastic bottles for guests for fear of appearing cheap and insensitive.''

Many respondents were sceptical plastic-bottled beer would remain cold and fresh. ``Others worried about the taste, with a strong minority comparing plastic-bottled beer to plastic-bottled soda, which they felt was an inferior product.''

Leading packaging group Sidel has estimated that by 2002 plastic could take five percent of the beer packaging market, estimated at some 300 billion containers per year.