My experience at the store/ when ordering drinks has been that I'd get the replies more often than not in Finnish and had to switch to English myself when it was something that I didn't understand. Key is to get the pronunciation right - which is far easier as a German.

And yes, younger people know English well and will usually switch to English if you're struggling - unless they think that their English is too bad (which it usually isn't).

Alcohol is very expensive though!