Carlsberg and Heineken plan to only brew beer using malt produced from null-lox barley varieties by 2013, said Stuart Shand, sales director for sole null-lox agent, Gleadell.

Null-lox varieties were grown commercially in the UK for the first time last season and the area in the ground this year had doubled, he said. “It took up about 5% of the UK spring area last season, and we are hoping to increase this to over 15% next spring.”

Null-lox barley was developed by Carlsberg’s in-house research centre, with assistance from Heineken, to help keep beer fresher for longer. The firms plan to phase out malt produced from conventional varieties over the next couple of years, he said. “They really like it as it extends the shelf-life considerably.”

The reason the beer keeps fresher for longer is that the lox enzyme present in conventional barley kernels, which causes beer to lose its flavour over time, was bred out of the Null-lox lines, said Mr Shand.

Two null-lox varieties were currently available in the UK and five more were in trials, he said.