Full Idea
Aristotle never thought of an essence as comprising all the necessary properties of an object. In Met VII.4 he limits per se predication appropriate to essences to the definition, and in Topics he distinguishes definition from the 'proprium'.
Clarification
'Proprium' translates 'idion', and means non-essential properties
Gist of Idea
Essence is not all the necessary properties, since these extend beyond the definition
Source
report of Aristotle (Metaphysics [c.324 BCE]) by Charlotte Witt - Substance and Essence in Aristotle 4.1
Book Reference
Witt,Charlotte: 'Substance and Essence in Aristotle' [Cornell 1994], p.106
A Reaction
[Topics 102a20-25] There seems to be consensus among scholars about this, and only a few misguided modern metaphysicians identify essences with the necessary properties (or maybe the non-trivial necessary properties).