The distillers are organizing an online petition to the Department of the Environment, Food and Rural Affairs, The Times of London reported. They say the Scotch Whisky Association, which proposed the "blended malt" designation, is promoting large liquor companies over the interests of small distillers.

Blended Scotch now describes a mix of grain and malt whiskey. Whiskey combining malts from different distillers is sold under a number of names, including "pure malt."

Jim Murray, author of "Jim Murray's Whisky Bible," believes the association is making a big mistake.

"It is boom time for the industry but this is totally confusing and it has to be stopped," he said.

The association says adding categories will be helpful to drinkers. The plan, which must be approved by Parliament, would have five categories: single malt, single grain, blended malt, blended grain and blended whiskey.