how is coffee decaffeinated?

by John Herriott

Coffee is decaffeinated through a process that removes most of the caffeine from the coffee beans while preserving the flavor compounds. There are several methods of decaffeination, and each method involves extracting caffeine from the green coffee beans before they are roasted. Here are some common decaffeination methods:

  1. Solvent-Based Processes:

    • Direct Solvent Method:
      • The green coffee beans are steamed to open their pores.
      • A solvent, such as ethyl acetate or methylene chloride, is used to extract caffeine from the beans.
      • The solvent is then removed, taking the caffeine with it.
    • Indirect Solvent Method:
      • Similar to the direct method, but the beans are first soaked in water to dissolve caffeine.
      • The water containing dissolved caffeine is then combined with a solvent to extract the caffeine.
      • The solvent is separated, and the water is returned to the beans.

  2. Swiss Water Process:

    • This is a non-solvent method.
    • Green coffee beans are soaked in hot water to extract caffeine and coffee solids.
    • The water is passed through activated charcoal filters, which selectively remove caffeine while allowing other coffee compounds to remain.
    • The caffeine-free water is then used to decaffeinate a new batch of beans.
    • The beans are rehydrated with the caffeine-free water.

  3. Carbon Dioxide (CO2) Process:

    • Green coffee beans are soaked in water to expand them.
    • The beans are placed in a high-pressure chamber with liquid carbon dioxide.
    • The CO2 acts as a solvent, extracting caffeine from the beans.
    • The caffeine-rich CO2 is separated from the beans, and the beans are then dried.
    • The caffeine can be recovered from the CO2 for reuse.

  4. Triglyceride Process (Sugar Cane Ethyl Acetate):

    • Green coffee beans are soaked in water and a solution of ethyl acetate derived from sugar cane.
    • The ethyl acetate binds to the caffeine molecules and is then separated from the beans.
    • The beans are steamed to remove any remaining solvent.

After decaffeination, the green coffee beans are dried and ready for roasting. It's important to note that while these processes remove most of the caffeine, they do not eliminate it entirely. Decaffeinated coffee typically contains a small amount of residual caffeine.

Consumers can choose decaffeinated coffee based on personal preferences and considerations, such as the decaffeination method used and the desired flavor profile.

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