Think they wash it in coffee. Caffeine leaches out, coffee flavour stays in. This is based on a brief glance at something 20 years ago.
They then sell the caffeine for more than they sell the coffee…
Not in that specific (Swiss Water) case, you wash the beans in ‘coffee’ then filter the coffee through charcoal to remove the caffine, then re-use the coffee. It’s the only process that doesn’t allow for the recovery of caffeine.
The other options are:
Super-critical CO2 (i.e. CO2 at such high pressure that it has the density of a liquid, but the viscosity of a gas).
Ethyl acetate.
Di-chloro Methane is used as well, but this is potentially carcinogenic. It is however viewed as ‘the best’ in terms of retaining coffee flavors, so still used. Especially if you’re buying from some posh swanky hipster artisan coffee roasters. I’d not worry though, the FDA safe level is 10ppm, after steaming it’s nearer 1ppm, it then spends 15minutes in the roaster at 200C (boiling point of DCM is about 35C), then you make coffee with it at 100C, there isn’t a notable amount in your coffee.
CO2 is used via the indirect process (CO2 is mixed with the water like the charcoal is in the Swiss process), the other two can either be done this way (so the beans only ever contact trace amounts of solvent anyway) or by directly soaking the beans in the solvent.
Ohh and ‘naturally decaffeinated’ usually means washed in ethyl acetate, why? Because ethyl acetate is naturally occurring in fruit. The fact that the stuff used to extract caffeine is likely from an oil refinery is an inconvenient truth.
