Which method is used to decaffeinate coffee?

The decaffeination process of coffee primarily involves three main techniques: water processing, the CO2 method, and solvent-based methods.

In water processing, often referred to as the Swiss Water Process, beans are soaked in water to dissolve the caffeine. The water is then passed through a carbon filter, which captures the caffeine, allowing the flavors and oils to remain in the water. The beans are then reintroduced to this caffeine-free water to reabsorb the flavors.

The CO2 method employs carbon dioxide under high pressure, which selectively binds to caffeine in the coffee beans while leaving most of the other compounds intact. This method is highly effective at preserving the coffee's flavor profile.

Finally, solvent-based methods involve using chemical solvents, typically ethyl acetate or methylene chloride, to extract caffeine from the beans. The beans are steamed to open their pores before being rinsed with the solvent, which then removes the caffeine.

The other options do not accurately describe recognized methods for decaffeinating coffee. Electrolysis and heat extraction are not standard practices in the decaffeination process, and filtration, while it might remove impurities, does not specifically relate to the removal of caffeine from coffee beans.