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  • 2.10.6-THE MARKETS FOR COFFEE-THE DECAFFEINATION PROCESS

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  • The decaffeination process

     
     
    Arabica coffee beans contain 1%–1.5% caffeine, whereas robusta contains more than 2%. Caffeine is an alkaloid with stimulant properties that are pleasing to the majority of coffee drinkers, but not to all. Decaffeination caters for those who for whatever reason do not want the stimulant effect of caffeine.

    The caffeine in the green coffee beans has to be extracted. Different processes are used. The solvents are water, organic extraction agents or carbonic acid. The processing steps are vaporization, decaffeination and drying. All these steps are carried out using the green coffee bean.

    First the green coffee is treated with vapour and water to open up the bean surface and the cell structure to access the crystalline caffeine taken up on the cell walls. The second step is the extraction of the caffeine by an extraction agent which has to possess the ability to extract only the caffeine. The caffeine extraction is not a chemical process but a physical one. No chemical changes take place. Instead differences in the characteristics of the extraction agent, which has to absorb the caffeine, and the beans containing the caffeine, are used. The extraction agent absorbs the caffeine selectively. Once the extraction agent is saturated with caffeine the next processing step removes the caffeine and the extraction agent can be used again.  This cycle is repeated until practically all the caffeine is removed from the coffee bean. Then the wet coffee, from which the caffeine has been removed, is dried until once again it reaches its normal moisture content. It can then be roasted as usual.

    The following decaffeination agents are allowed in the European Union: methylene chloride, ethyl acetate, carbon dioxide, and watery coffee extract from which the caffeine is removed by active carbon. All conventional decaffeination methods have undergone intensive scientific examination and are considered safe. In the European Union the absolute caffeine content in roasted, decaffeinated coffee may not exceed 0.1%, or 0.3% in soluble coffee. In the United States, 'decaffeinated' is generally taken to mean that the caffeine content has been reduced by 97%, or to less than 3% of the original content.