"Bitter" for Tea and "Bitter" for Beer

George Orwell said “ Tea is meant to be bitter, just as beer is meant to bitter” in his writing, A Nice Cup of Tea.

I like it, but my interest here is the word “bitter”. 

Unlike English language, Japanese has different words between bitter for beer and the one for tea. I mean “nigai” for beer, and “shibui” for tea. Also we say “nigai” chocolate for bitter chocolate, and "nigai" coffee for bitter coffee. We say “shibui” green tea for bitter green tea.

I know that English language has the word, astringency, for tea. But it is interesting to know  that “bitter” can be covered the taste both of beer and tea. 

Shibui” is astringency like tea while “nigai” is bitterness like beer, coffee, dark chocolate etc. If you are a tea person, it does no harm to know it.