Tasteless, if popular drink I had (7)
I believe the answer is:
insipid
'tasteless' is the definition.
(synonyms)
'popular drink i had' is the wordplay.
'popular' becomes 'in' (something that's 'in' is fashionable).
'drink' becomes 'sip' (sipping is a kind of drinking).
'i had' becomes 'i'd' (I'd).
'in'+'sip'+'id'='INSIPID'
'if' is the link.
(Other definitions for insipid that I've seen before include "Lacking in flavour or interest" , "Dull" , "Bland, flavourless" , "Lacking flavour or banal" , "Lacking 10" .)