Some authorities (such as Swan) suggest that we should not use the labels 'countable' and 'uncountable', but should instead talk about how a noun can be used. Some so-called 'uncountable' nouns are actually capable of being used both as an uncountable noun and as a countable noun. As a countable noun they can have a plural form, and the verb has to agree.
In your example, there are two distinct types of beer - English beer and Italian beer - so there are two beers.
It's possible to do this with other products - cheeses, milks, wines, butters...
It's also possible to use a plural with some beverages. We can ask for 'two teas' (= two cups of tea) or 'three coffees' (three cups of coffee). However, for some reason we don't, normally, ask for 'two wines' when we want two glasses of wine.
With 'completely' uncountable nouns (luggage, advice, furniture...) we cannot use a plural form and thus only a singular verb will do.