"Onlar birayı severler."
Translation:They like the beer.
If I had had to translate "They love beer" into Turkish, I might have erroneously said, "Onlar bira severler" because it isn't "the beer" but beer in general. But do you use "yı" ending because you always need the accusative with the verb "sevmek"?
"Onlar bira severler" is also correct. I think when talking about food and drinks, you can leave the accusative out if it's in the general sense.
Aha! So my instinct was not incorrect! Teşekkür ederim, Ektoraskan! If it wasn't 8:40 a.m. here, I'd have a beer! :)