et øl og en øl
I assume the difference is very nuanced, but quite what it is escapes me. Has anyone got any advice on this one, and are there more like this?
The one you will hear most often is "en øl". This would be used in the following circumstances:
Talking about "a beer", as in a pint/glass/bottle of beer. "Jeg kjøpte en øl i baren" - "I bought a beer at the bar".
Talking about type/brand of beer: "Hva slags øl liker du?" Jeg synes Atnabryggeriet har en god øl, den heter Rypeøl." (What kinds of beer do you like? I think Atna brewery has a good beer, it's called Rypeøl (ptarmigan beer)).
Et øl is more for talking about beer that is spilled, unnamed beer in large quantities, the liquid:
"Han tråkket i ølet som var sølt utover gulvet" - "He stepped in the beer that was spilled on the floor". "I Norges kongesagaer står det om kong Fjolne, han druknet i ølet som stod i et åpent kar i huset hvor han sov." - "In the Norwegian king's sagas there's a story about king Fjolne, he drowned in the beer that was kept in an open vat in the house where he slept."