Five thousand litres of beer were dumped yesterday after a burst water main affected production at the Emerson Brewing Company's Dunedin brewery.
Production manager Chris O'Leary said the lost brew of Emerson's Pilsener was the equivalent of 10,000 bottles.
"It will break a lot of people's hearts."
A truck and trailer unit in Wickliffe St is believed to have damaged the water main at 11am.
It was repaired by the Dunedin City Council, with the water supply affected again at 4pm.
"We can't run the brewery satisfactorily without water."
Water was required to chill the brew so yeast could be added, and also to fill the hot-water tank.
A planned batch of the seasonal beer, Taieri George, might also have to be dumped today, if the problem was not remedied.
The dumped brew could not have come at a worse time for the award-winning brewery.
It was trying to catch up on production following a "ripper" Christmas period, Mr O'Leary said.