Actually the sentence can be read in two ways.
The logical way is to understand that you are talking about a man (can be the guy standing over there) and say about him that he is a wise man, who invented beer.
In that case, a comma could be added after man, but it is not necessary. If "inventing beer" is the reason I call him a wise man, no comma is needed.
Compare to:
He is a smart man who founded Microsoft.
Now, it is reasonable to assume that the man who invented beer, in contrast to Bill Gates, is no longer among us, which means it is unlikely I will refer to anyone in this way.
The interpretation that is left then is indeed
The man who invented beer was wise.
Whether that happened a long time ago or yesterday is not relevant.
I would not say he is if I wanted to convey that message though, I would say:
It was a wise man who invented beer.
To avoid the possible interpretation that I am talking about an actual person that we should somehow know about.