Drink in a fine yarn about California (9)
I believe the answer is:
americano
'drink' is the definition.
(type of coffee drink)
'a fine yarn about california' is the wordplay.
'fine yarn' becomes 'merino' (I've seen this in another clue).
'about' is an insertion indicator.
'california' becomes 'ca' (abbreviation).
'merino' enclosing 'ca' is 'mericano'.
'a'+'mericano'='AMERICANO'
'in' is the link.
(Other definitions for americano that I've seen before include "drink" , "Espresso diluted with hot water" , "Style of coffee" .)