About how many grams of caffine could be extracted from 10lbs of coffee beans?

[Phhase]

Can I ask why the OP wants to extract caffeine from coffee?

Ah, well, strictly speaking, I'm playing in a D&D campaign where my DM and I are both chem enthusiasts, and I am trying to prepare a potentially lethal dose of caffeine by weight for a vampire my character has a vendetta against (caffeine has already been shown to act as a potent hallucinogen for vampires rather than a stimulant).

I understand that's semi-relevant context, and I would've posted this on the RPG board, but I was also interested for my own sake and thought this board might have a more precise answer, since the question really had no founding in any of the game's systems.




...what about the catgirls?