Go to the Black Morass in the Caverns of Time and obtain 10 Essences of Infinity from Rift Lords and Rift Keepers. Bring these along with 5 Elixirs of Major Defense, 5 Elixirs of Mastery and 5 Elixirs of Major Agility to Lorokeem in Shattrath's Lower City.
WARNING! You can only select one alchemy specialization.
These are the amount of materials needed to create all of the elixirs:
I've devoted my life to perfecting my elixirs. Despite my success, I haven't been able to create an elixir of eternal life.
This intrusive time-shifting creates tears in time itself, twisting it infinitely into crystallized essences. Bring these to me along with samples of your work and I'll teach you all I know.
The essences! Do you have them?
You will learn: Elixir Master
Note: If you have already specialized in a different mastery and would like to respecialize in this one, you are not required to complete this quest. You are only required to pay the 150 gold to unlearn your current specialization. See Alchemy Specializations.
+250 Lower City faction
You are very good with elixirs, if these are any indication. You will make a fine student.
These essences will provide me enough materials to formulate my recipe. I will be known among all alchemists for this discovery!
Now, if you're willing to learn, I am willing to teach.
There is only a 3% percent chance that a Rift Lord/Keeper will drop the Essence of Infinity required for this quest, so expect to spend a lot of time wading around in the Black Morass. (Note: the chance drops to 1% in Heroic mode.)