The Cornish brewer, which became part of the Molson Coors empire earlier this year, sold 9,088 firkins in the week to April 8, the highest weekly sales volume since the brewery's launch in 1994.
The company has ordered three new fermentation vessels which will increase production by a further 24,000 brewers barrels a year.
Head brewer Stuart Howe said: “We are delighted with the progress we are making. Sales of Doom Bar have grown by more than 45% this year, and are still rising.
“We are enormously ambitious for Sharp's Brewery, including Doom Bar and the whole portfolio of Sharp’s beers. The investment in the brewery is essential to keep pace with the growth we are experiencing and realise our goal of being the largest brewer of cask conditioned beers in the UK.”