Australian barley growers need to be aware of varietal purity when preparing their seed for the coming season.

GRDC Western Panel member David Capper said varietal purity of malting barley was critical as it dramatically affected malting and brewing performance and this was the time of year growers considered seed for sowing next year.

"Receival standards for varietal purity are 95 per cent, however export customers usually demand a 98 per cent purity minimum. Unfortunately, there is no receival point test for varietal purity, so the system relies on growers' declarations being accurate.

"Varietal purity isn't just an issue for growers. Everyone in the grain supply chain plays a part. Breeders, commercial seed growers, seed cleaners and bulk handlers can all contribute to varietal impurities and need to continually review their practices," Mr Capper said.

Varietal purity testing is available through numerous sources, including the CBH Group and the Department of Agriculture and Food.