eli5 How exactly does one “de-caffeinate” coffee? Are they actually removing the chemical?

Question

eli5 How exactly does one “de-caffeinate” coffee? Are they actually removing the chemical?

In: 548

Answer 1

The beans are submerged in “supercritical” carbon dioxide. A supercritical fluid is a state of matter with both the properties of a liquid and a gas. The liquid property of the fluid allows substances to be dissolved in it (in this case the caffeine), the gas like properties of the fluid allow it to fully permeate the beans, extracting caffeine from within.

If the carbon dioxide was in normal liquid state it would only touch the outside of the bean, so only the surface level caffeine would be extracted