The most common and most likely answer to this crossword clue is the 12 letter word DISTILLATION
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result DISTILLATION
Buddy explains!

The straight part
We know that "Essence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case essence = distillation.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DISTILLATION mean?
DISTILLATION noun- The act of falling in drops, or the act of pouring out in drops.
- That which falls in drops.
- (chemical engineering) The separation of more volatile parts of a substance from less volatile ones by evaporation and condensation.
- The substance extracted by distilling.