Hey dpurdy, thanks for your reply.
Uhm, turned out that I was wrong, and stupid. Long story short, I had to clean up (I do my mixing at the kitchen table) and after putting everything in bottles I had 5L after all. (Strange, because I weighed it (on a scale going to 5kg) after removing +- 1L it still weighed about 5kg...)
I was thinking of removing this post, but since I had troubles finding something about this, I'm going to let it be. Carry my stupidity into the future!!!