Alternative to a beer (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
cider
(Other definitions for cider that I've seen before include "Scrumpy" , "Alcoholic drink made from apples" , "Alcoholic drink (to be taken with Rosie?)" , "Beverage from apple juice" , "Alcoholic drink from fermented apple juice" .)