Educate the curious: Decaf Process
A common belief is that coffee becomes decaffeinated by roasting it for a long time, but that is far from the truth. In fact, it takes the same amount of time to roast our decaf Colombian coffee as it does our regular Colombian offering.
There are four common methods for removing caffeine from coffee beans. These descriptions of the four methods are taken from How is Coffee Decaffeinated? Top 4 Methods written by Kate MacDonnell.
- Direct Solvent Process (also known as Ethyl Acetate / EA Process)
To make the decaffeination process easier, the beans are softened by either soaking in water or being steamed. When ready, the coffee beans are repeatedly exposed to a solution containing either solvent, methylene chloride, or ethyl acetate.
Usually, ethyl acetate is used for this method. It’s advertised as a natural way to remove caffeine from coffee because the chemical is naturally found in fruits. (For example, a naturally obtained byproduct of the fermentation of sugar cane.)
This process goes on for about 10 hours. Once the beans have been fully exposed to the solution, they are usually steamed to get rid of any remaining solvent.
This is the process used for our current Colombia Decaf coffee!
- Indirect Solvent Process
The indirect solvent process begins by soaking the beans in boiling water. This draws out all the water-soluble contents, including caffeine and a lot of flavor compounds. The coffee beans are then removed from the liquid, which now contains all the water-soluble contents of the beans.
Next, methyl chloride is added to the liquid. When the liquid is heated, the methyl chloride evaporates the caffeine. Once all the caffeine is dissolved, the coffee beans are then reintroduced to the mixture to regain the flavor compounds that were lost in the initial exposure. With this, the coffee beans never contact the chemical.
This process is the most widely used method for decaffeination.
- Carbon Dioxide Process
As with the above two processes, the supercritical carbon dioxide method requires water-soaked green coffee beans to start. These coffee beans are placed in a stainless steel vessel that acts like a pressure cooker.
The coffee beans are then exposed to 73 to 300 atmospheres of supercritical (highly compressed) carbon dioxide for ten to twelve hours. At this amount of pressure, carbon dioxide’s properties are enhanced, causing it to be dense like a liquid while still being a gas.
The caffeine-containing carbon dioxide that exits the container is usually filtered through activated charcoal. From there, the carbon dioxide is funneled back into the stainless steel container to repeat the process.
- Swiss Water Process
The Swiss water process is said to be the cleanest method of removing caffeine from coffee, since water is the main solvent. To start, the green beans are soaked in a mixture of water and green coffee extract.
The solution is filtered through activated charcoal, which separates the caffeine from the mixture. The solution is then channeled back into the coffee beans until they’re 99% free of caffeine.
This method began in Switzerland in the 1930s, but now the main facility operates out of Vancouver, BC. It’s also the preferred method of a lot of organic coffee companies.
Leave a comment