CO2 decaffeination of coffee

What is CO2 decaffeination of coffee?

The latest method of decaffeinating coffee developed by Kurt Zosel, a scientist from Max Plank Institute, uses carbon dioxide CO2 instead of chemical solvents. It acts selectively on caffeine, i.e. it releases the alkaloid and nothing else. It's not enough to just blow to eliminate caffeine. To do this, CO2 must be converted into its liquid form (called a solvent).

In the CO2 coffee decaffeination process, water-soaked coffee beans are placed in a high-pressure tank (operating at a pressure of about 250 to 300 times greater than atmospheric pressure) made of stainless steel. This so-called extraction chamber is then sealed and liquid CO2 is forced into the coffee at a pressure of 69 bars per square inch. At these pressures, carbon dioxide acquires unique "supercritical" properties that increase its usefulness as a solvent that draws caffeine from coffee beans and dissolves it, leaving behind larger-molecule flavor components. Once the caffeine has been successfully extracted, the caffeine-rich carbon dioxide is transferred to a low-pressure absorption chamber that allows the CO2 to return to a gaseous state. The caffeine-free CO2 gas will then be compressed into liquid form a second time in a pressurized container and once again introduced into the coffee beans. This is a slow process that continues until virtually all the caffeine has been removed from the beans - typically it can extract between 96 and 98% of the caffeine originally present in the coffee. This may take up to four days!

Using the power of nature in the coffee decaffeination process

The only ingredients used in the decaffeination process are water and carbon dioxide, which means it is completely organic! An example of coffee where caffeine has been released is carbon dioxide decaffeinated coffee Nicaragua Fincas Mierisch Los Placeres

What happens to the remaining caffeine?

EU regulations set a maximum caffeine content of 0,1% after each coffee decaffeination process. This means that 99,9% must be removed. The removed caffeine is then collected as a powder and compressed into chalk sticks. It is used in the pharmaceutical industry (e.g. flu tablets), food industry (e.g. cola, energy drinks) or is sold in powder form.
As some of you may have already noticed, the appearance of coffee beans containing caffeine differs significantly from those without it. And although all the aromatic and aromatic compounds remain locked in the coffee "chamber", these beans tend to turn chocolate in color with a dark central cut. You can read more general information about decaffeination of coffee and decaffeinated coffee itself here.