Wine casks developed eccentric quality (9)

I believe the answer is:

wackiness

I'm a little stuck... Click here to teach me more about this clue!

'eccentric quality' is the definition.
The definition suggests a singular noun which matches the answer.

'wine casks developed' is the wordplay.
'developed' indicates anagramming the letters.
'wine'+'casks'='winecasks'
'winecasks' anagrammed gives 'WACKINESS'.

Can you help me to learn more?

I've seen this clue in The Daily Express.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.

Connecting...