Dampened Spirits

Dampened Spirits is a quest given to you after joining the Thieves Guild. After completing the quest 'Loud and Clear', Brynjolf will tell you that Maven Black-Briar wants to speak to you.
 * 1) Speak with Maven Black-Briar.
 * 2) *She will be waiting for you upstairs in the Bee and Barb. She'll tell you that she needs you to get rid of the competition, a brewery that's just opened and wants you so find out how Sabjorn has managed to fund such a costly project.
 * 3) Speak with Mallus Maccius.
 * 4) *He'll be waiting for you in the Bannered Mare in Whiterun. He asks you to talk to Sabjorn so you can get into the basement to clear out the pests he's having a problem with and poision the vat in the process.
 * 5) Poision the nest and Honningbrew vat.
 * 6) *Speak with Sabjorn and he'll let you do the job without many complaints.
 * 7) *Getting to the nest is pretty straight forward, there are quite a few skeevers and a few frostbitespiders to deal with. What you need to watch out for is Hamelyn, a man who appears to have been living next to the nest, he has a fairly powerful fire attack so keep an eye on your health bar. If you are having trouble with him and have the ability to transform into a werewolf I recommend doing so; your growl will cause him to go into "fear", you then have the chance to kill him.
 * 8) *Continue through the tunnel to the Honningbrew Boilery, go up the stairs and pour the poison into the vat. The key for the door is hanging up right next to it so you can leave without having to backtrack.
 * 9) *Go back into the meadery and tell Sabjorn the job is done.
 * 10) Attend the tasting ceremony.
 * 11) *Commander Caius tastes the mead and is unhappy with it, he then puts Mallus in charge and drags Sabjorn off to Dragonsreach Dungeon.
 * 12) *Talk to Mallus Maccius and he'll tell you where the books are that will help you locate Sabjorn's 'silent partner'.
 * 13) Identify Sabjorn's silent partner.
 * 14) *Go upstairs and look in Sabjorn 's dresser there should be a promissory note.
 * 15) *Unlock the door to the right of the dresser. Inside this rooom you will find the Honningbrew Decanter, which you sell to Delvin Mallory.
 * 16) *Travel back to Riften and give Maven Black-Briar the note.
 * 17) *She tells you to take the information to Brynjolf.

Rewards
Upon returning to Maven Black-Briar you will be given a reward of a leveled weapon with a random enchantment on it.

Note: If you do not speak to Maven Black-Briar shortly after being given the quest, the quest will bug out and you will not be able to continue with the Thieves' Guild quest line. This is an issue as of 10/17/2011.