有一种东西叫谷歌

来源: dudaan 2009-10-26 09:18:33 [] [博客] [旧帖] [给我悄悄话] 本文已被阅读: 0 次 (2804 bytes)
三种方法:
The Swiss Water Process Method

The Swiss Water Process is popular among its advocates because it does not use chemicals. Instead, a green coffee extract is used. This green coffee extract is almost caffeine-free. Due to chemical solubility laws, the caffeine will move from an area of higher concentration (the bean itself) to an area of lower concentration (the extract). Since the extract contains essential oils and the other valuable components of the bean, mostly caffeine seeks its way into the extract and leaves behind the desirable components of the coffee. Done properly, this organic method successfully removes 94 - 96% of the caffeine while it retains more of the flavor compounds present in the essential oils than the chemical methods. Keep in mind that Swiss Water Process coffee beans are generally more expensive than beans treated with a chemical solvent. This is due to the fact that Swiss Water Processing almost always accompanies high-quality arabica beans, while chemical processes are used on both arabica and robusta beans.

The Chemical Solvent Method

The chemical solvent method is the most commonly used method for removing the caffeine from coffee. Chemical methods remove the caffeine better than the Swiss Water Process method because the solvents used can target caffeine most evenly and effectively. Common solvents include methylene chloride, ethyl acetate, and highly pressurized carbon dioxide. After the green beans are moistened they are then immersed in the solvent. After the solvent performs its action, the beans are rinsed with water. After the beans have been rinsed, they are steamed. Residual solvents evaporate in the steam. The rinsing and evaporation systems collect the solvent for recycling and re-use. Any remaining solvent will be burned off in the roasting process. The chemical caffeine method will remove 96 - 98% of caffeine.

The Supercritical Carbon Dioxide Method

The Supercritical Carbon Dioxide method is a chemical method that is somewhat dissimilar to the other chemical methods; therefore it deserves special attention. This method uses carbon dioxide at 250 - 300 times normal atmospheric pressure. Carbon dioxide in this form looks like a liquid in terms of its density, but it has the viscosity of a gas. It is a very effective solvent at the high pressures. When the coffee beans are exposed to the solvent, the caffeine migrates to the solvent. When the removal of caffeine is complete, the now caffeine-rich carbon dioxide is passed through either an activated charcoal bed or a bath of water to absorb the caffeine for re-use. Like other chemical methods, the Supercritical Carbon Dioxide method removes 96 - 98% of the caffeine. Carbon dioxide is inexpensive to obtain and non-toxic.

所有跟帖: 

谷歌也能全信? -mychina- 给 mychina 发送悄悄话 mychina 的博客首页 (0 bytes) () 10/26/2009 postreply 09:31:28

当然不能全信,就看你的眼力了,这还用说吗? -dudaan- 给 dudaan 发送悄悄话 dudaan 的博客首页 (0 bytes) () 10/26/2009 postreply 09:53:57

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