Go into any real ale pub and you will see a man (or woman) holding their drink up to the light and gazing through the glass, through the beer.
A clear beer is the sign of a good beer (with the exception of wheat beer).
But I wonder how many drinkers realise that that clarity comes from ... fish guts.
Of course, you will never be told "oh, we use fish guts to clear the beer."
No, they will tell you they use Isinglass. That's the fancy word for fish guts.