Lost Thunderbrew Recipe

The Lost Thunderbrew Recipe shows how to brew Thunderbrew Lager, an ale created by Ragnar Thunderbrew which is reported to give the inbiber great strength. The recipe was stolen by Hurley Blackbreath of the Dark Iron Dwarves.

Source
This item drops from Hurley Blackbreath in the Grim Guzzler tavern in Blackrock Depths.