Sadly, it’s impossible to remove caffeine without sacrificing a bit of aroma and flavor from other chemical compounds that get removed along with it. A chemist explains the 3 methods used:

1. High-pressure CO₂ taking the caffeine from moistened beans

2. The swiss water process: cooking batches and using activated charcoal

3. Solvents: either soaking the moist beans directly in the solvent or in a water solution containing the solvent