Untold story of CO2

Some useful Facts (Carbon Dioxide)

Another benefit of carbon dioxide (not in the form of dry ice) that is often overlooked is its application in the extraction process, such as extraction caffeine from coffee bean to produce decaffeinated coffee. The extraction process does not directly use dry ice. Rather, it uses carbon dioxide in the form of "Supercritical Fluid", which is the carbon dioxide gas that has been pressurized and heated until the point where distinct liquid and gas phases do not exist. This particular point is referred to as the critical point.

Above the critical point, carbon dioxide will behave as a supercritical fluid adopts the properties midway between gas and liquid, such as diffusing like a gas but with higher density than typical gas and can be melted like a liquid.

Due to these beneficial properties, supercritical carbon dioxide can be used to extract compounds or substances from one another by acting as an extraction solvent. As such, it can be used to extract caffeine from the coffee beans while retaining other characteristics such as color, smell and taste of the coffee.