Essence was a poetry "little" edited and published by Joseph Payne Brennan (1918-1990) in New Haven, Connecticut.
Essence ran 47 issues from 1950 to 1977.
Among the many poets who contributed over the years were George Abbe, Duane Ackerson, Judson Crews, August Derleth, Alan Donovan, Alfred Dorn, Janet Fox, Skip Galloway, Joseph Joel Keith, Lilith Lorraine (Challenge, Different, Flame), John Francis Murphy, William J. Noble, Lori Petri, Sydney King Russell, Wade Wellman, and Celeste Turner Wright.
Joseph Payne Brennan also published the literary fanzine Macabre.
Joseph Payne Brenna entry at Wikipedia