Lost Thunderbrew Recipe

It is rumored that the Dark Iron Hurley Blackbreath has stolen a recipe for ale. This ale, Thunderbrew Lager, is said to infuse its imbiber with great strength and courage. We wish to study the drink. Perhaps, we will find other applications for its virtues... applications more in line with Forsaken objectives. Delve into Blackrock Depths, find Hurley, take from him the recipe for Thunderbrew lager and bring it to me. And to find him, you may have to entice him by threatening his precious ale.