Save Brewfest!

(Horde instructions for getting pre-quests; according to Miyari's Post it's NOT necessary to complete these to get the daily, Insult Coren Direbrew)

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• Have each party member complete "Welcome to Brewfest!" from Tapper Swindlekeg outside Orgrimmar.
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• Grab "Save Brewfest" from Slurpo Fizzykeg, on the road south towards Razor Hill. The quest is shareable if other members have completed "Welcome to Brewfest!" Turn it in to the Brewfest Spy in the Grim Guzzler, BRD.
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• Pick up the daily, Insult Coren Direbrew, from the Brewfest Spy. Turning this quest in to Coren aggros him and completes the daily. You only get one chance to kill him per turn-in; make sure 2 party members don't turn in at the same time, as it will waste one of your tries at killing him.
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Though this boss is a pushover for well-geared people, those needing his trinkets might have a bit harder time.

Here's a brief description of the fight:
1. He'll start with 3 non-elite adds. Tank should stay on Coren and have a designated DPS take out the adds. Non-elite adds will continue to spawn throughout the fight via tunnel-borer machines that pop up out of the ground. These are easy to kill quickly.
2. At about 66% and 33% health he'll summon an elite barmaid (Ilsa and Ursula Direbrew). DPS should ignore them (alternate strategy is to burn them down immediately, but not necessary unless your DPS/healers are very squishy). The tank should apply some aggro to keep them off the healer. They despawn (as well as all other adds) when Coren dies.
3. Coren does a whirlwind attack that hits players in melee range. Coren will also disarm the tank and everyone in melee range; there's a long cast bar preceding this. Watch for the drop in threat generation.
4. The elite barmaids throw out beers that land in your inventory, apparently at random targets. If you don't drink the beer ASAP, and they throw a second one at you, you'll get stunned for about 5 seconds.
5. Barmaids will randomly "Keg" party members. It seems this usually happens to the tank first; the keg lands on your head and CC's you for about 6 seconds. This is the hardest part of the fight if not controlled properly, as Coren will go after whoever is 2nd on the threat list. You can sometimes get chain-Kegged at maddeningly short intervals.

Hope this helps, and enjoy your trinkets!

Edit - updated quest pre-reqs and barmaid behavior, thanks to the posters below that pointed out the beers in the inventory.

OK, here's how to get the quest (horde side):

First get and complete the quest "Welcome to Brewfest!" from Tapper Swindlekeg, who is standing at the entrance to the main "Drinking area".

After that, head south towards Razor Hill, and there you will find Slurpo Fizzykeg, who now has the quest "Save the Brewfest".

Hijink - (EU)Twisting Nether

Okay, here's how it goes:

Starts by accepting the Save Brewfest! quest from Darna Honeybock in Kharanos (sorry, I know about the Alliance side only), which will ask you to talk to an undercover spy inside BRD.
Once inside BRD you click on a pile of booklike objects right by entrance to be teleported to Coren's room where you'll find the spy in question, Coren Direbrew and a few other dwarves (neutral). You finish the quest by addressing the spy, only one person does that per group.
This will trigger another quest that will require you to address Coren, then of course he attacks you.
(of course you can just skip all that and go directly to BRD to take the daily if you're not into following lore).

He's level 75-80 boss, pretty easy tank and spank fight, a few elite adds will pop but that's about it.

His loot table:
1st time you fight him, he will drop Direbrew's Dire Brew which you can turn into Ipfelkofer Ironkeg for 40 Brewfest Prize Tokens, then..

A) Guaranteed to drop one of these epic trinkets:
-Ancient Pickled Egg.
-Brawler's Souvenir.
-Mithril Pocketwatch.
-Coren's Chromium Coaster.
-Bitter Balebrew Charm.
-Bubbling Brightbrew Charm.

B) Lucky Groups have a slight chance to finding:
-Direbrew's Shanker 2.0.
-Direbrew's Remote.
-Tankard O' Terror.

C) Very Lucky groups have a slighter chance to finding:
-Swift Brewfest Ram.
-Great Brewfest Kodo.

Once you trigger the quest to kill Coren, that counts as a daily. But you can still go as many times as you want after that with other people as long as there's someone in group that hasn't done the daily yet. So it's a good thing to check the quest log to see if everybody in your group has taken (is able to take) the daily quest prior to starting in order to fight him 5 times, 5 chances to getting the mount/epic weapon/remote. Good luck all. :D