Blend of Irish drinks bottled by Catholic church (8)
I believe the answer is:
coalesce
'blend' is the definition.
(synonyms)
'of irish drinks bottled by catholic church' is the wordplay.
'of irish' becomes 'o' (O' roughly means 'of' in some Irish surnames).
'drinks' becomes 'ales' (ale is a kind of drink).
'bottled by' is an insertion indicator (bottle can mean to contain).
'catholic' becomes 'c' (abbreviation as in RC for Roman Catholic).
'church' becomes 'ce' (abbreviation for Church of England).
'o'+'ales'='oales'
'c'+'ce'='cce'
'oales' inserted within 'cce' is 'COALESCE'.
(Other definitions for coalesce that I've seen before include "Combine with others as political parties may do" , "To bring together" , "Grow together, amalgamate" , "Make one whole" , "'Fuse, combine (8)'" .)