Crossword Genius

Port in Germany? Why not wine? (5)

Ross

I believe the answer is:

rioja

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

'not wine?' is the definition.
'rioja' can be an answer for 'wine?' (I've seen this before). I'm not certain of the 'not' bit.

'port in germany? why' is the wordplay.
'port' becomes 'rio' (Rio de Janeiro is a port).
'in germany? why' becomes 'ja' (I can't explain this - if you can you should give a lot more credence to this answer).
'rio'+'ja'='RIOJA'

Can you help me to learn more?

(Other definitions for rioja that I've seen before include "kind of red" , "North Spanish wine" , "Spanish table wine" , "Dry red wine from Spain" , "Spanish drink" .)

Want a hint initially instead of a full solution? Install my app