The Coffee Decaffeination Processes

What it is, how its done, and if its harmful.

Decaffeination Processes

What is decaffeinated coffee?
Decaffeinated coffee is coffee which has had almost all of the caffeine removed. Commercial decaffeination processes were initiated in Germany during the early part of the 20th Century. There are different methods of decaffeination, though the end result is more or less the same.

The three methods, all widely used, are; 'Water decaffeination', 'Solvent decaffeination' or 'Carbon dioxide decaffeination'.

Water Decaffeination
This method uses water to dissolve the caffeine from green coffee beans. This is done before roasting. Typically, water in run through coffee beans, creating an extract. The extract is then passed through activated carbon to remove the caffeine. The liquor containing water soluble components but without caffeine is then either concentrated and reincorporated on the decaffeinated beans, which have been partially pre-dried, or re-circulated through the beans and the caffeine is removed - this process is continually repeated.

Solvent Decaffeination
Solvents which can be used to selectively remove caffeine from green coffee beans include methylene chloride (dichloromethane), and ethyl acetate which is a natural component of fruits, vegetables and many other foodstuffs. The process involves using a solvent to dissolve the caffeine out of pre-wetted green beans. The solvent is removed, and the caffeine distilled out of it, so that the used solvent can be re-utilised in a further round of decaffeination. After completion of decaffeination the green beans are intensely treated with steam to remove all adherent traces of the decaffeination solvent. The decaffeinated green coffee beans are then dried, and ready for roasting. The roasting and grinding process further evaporates any minute residues of solvent, which might remain in the coffee, and there are strict European limits governing the levels of any solvent residues in decaffeinated beans. In fact, manufacturers operate well below these limits, ensuring the purity of the final product.

Carbon-dioxide Decaffeination
Caffeine can be made to dissolve out of pre-wetted green coffee beans when contacted with supercritical or liquid carbon dioxide, which is a normal constituent of air. This method does not involve the use of additional solvents, and the used carbon dioxide can be passed through active carbon to remove the caffeine, so that it can be recycled. The decaffeinated beans are then dried, and ready for roasting.

Some frequently asked questions about decaffeinated coffee

Q. What is the difference between caffeinated and decaffeinated coffee?
A. Decaffeinated coffee is simply coffee, which has had virtually, all the caffeine removed.

Q. At what stage is the caffeine removed?
A. All commercial procedures remove caffeine at the green bean stage, before the beans are roasted and have formed their aroma.

Q. How much caffeine is left behind in the coffee after it has been decaffeinated?
A. In Europe the absolute caffeine content may not exceed 0.1 % in roasted coffee and 0.3 % in soluble coffee. In the USA the caffeine content has to be reduced to less than 3 % of its original content.

Q. Is anything added to decaffeinated products that are not found in regular coffee?
A. No. Decaffeinated coffee is just as pure as regular caffeinated coffee.

Q. Why do manufacturers produce decaffeinated coffee?
A. The manufacturers strive to produce products which will suit every individual. Some people prefer to drink decaffeinated coffee. Caffeine is a mild stimulant, and some people who drink coffee do not always want the mild stimulatory effects. Many consumers drink both caffeinated and decaffeinated coffee. Manufacturers supply what consumers require.

Q. Does decaffeinated coffee taste different to caffeinated coffee?
A. The different blends of coffee beans used to produce the many types of coffee available result in subtle flavour differences. Some people may be able to detect a decaffeinated product.

Q. Is there any official legislation saying which solvents can be used for decaffeination?
A. Yes. The types of solvent used for decaffeination are governed by both national and European legislation.

Q. What about levels of solvent residues in coffee - are there laws about this?
A. Yes. Under EU law, dicloromethane residue levels in decaffeinated coffee must be under 2 parts per million. For ethyl acetate and carbon dioxide there are no legislative restrictions in most countries.

Q. So is decaffeinated coffee safe to drink?
A. Absolutely. There is no health risk whatsoever associated with drinking normal amounts of either caffeinated or decaffeinated coffee.