Archive for March 17th, 2010
Whether you call it unleaded or decaf coffee, many out there can’t drink the “real stuff” anymore. Here’s how they get the caffeine out but keep the taste in.
Various methods can be used. The process is usually performed on unroasted (green) beans, and starts with steaming of the beans. They are then rinsed with a solvent that contains as much of the chemical composition of coffee as possible without also containing the caffeine in a soluble form.
The process is repeated anywhere from 8 to 12 times until it meets either the international standard of having removed 97% of the caffeine in the beans or the EU standard of having the beans 99.9% caffeine-free by mass. Coffee contains over 400 chemicals important to the taste and aroma of the final drink; one can only imagine the difficulty of removing only the caffeine in this process.
While not every method uses the same exact process, the Swiss Water Process gives a good sense of how these processes work in general.
- A batch of green (unroasted) beans is soaked in hot water, releasing caffeine.
- When all the caffeine and coffee solids are released into the water, the beans are discarded.
- This solution then passes through a carbon filter that traps caffeine but lets the coffee solids pass through. The resultant solution is called “green coffee extract (GCE)”.
- New green coffee beans are introduced to the GCE. Since the GCE is coffee solids without caffeine only the caffeine diffuses from the new beans.
- The new GCE solution passes through proprietary carbon which captures the caffeine.
- Repeat process, filtering out all the caffeine until the beans are 99.9% caffeine-free.
- These beans are removed and dried, and they retain most if not all of their flavor.
Now you know, well, at least more.
Until next time – happy brewing.