| First, let's start with a really quick | | | | which is similar to the Traditional, Indirect |
| history. Coffee was first decaffeinated by | | | | Method, the beans are soaked in a hot water |
| Ludwig Roselius, a German coffee merchant, in | | | | solution to remove the caffeine and the |
| 1905 after he received a coffee shipment that | | | | flavor oils. The beans used in this step are |
| had gotten soaked during a storm at sea. He | | | | then discarded. The solution is run through |
| experimented with the brine-soaked coffee, | | | | activated charcoal filters to remove the |
| and found out that benzene could be used as | | | | caffeine, but leave the flavor oils. A new |
| solvent to bond with the caffeine. Since | | | | batch of beans is then soaked in the |
| caffeine is water-soluble at temperatures | | | | solution. According to the laws of osmosis, |
| above 175°, he could boil the solution to | | | | the caffeine leaves the beans to go to the |
| separate the caffeine from the coffee. With | | | | uncaffeinated solution, but the flavor in |
| his process, the coffee was decaffeinated, | | | | both the solution and the beans is equal, so |
| but it had lost much of its flavor. | | | | no flavor leaves the beans. |
| | | | |
| For the record, Ludwig improved on his | | | | The beans are then dried and shipped to the |
| process and went on to sell his discovery | | | | roasters. The disadvantage is that the water |
| under the Sanka brand name. Benzene is no | | | | processing removes more than just the |
| longer used, as it is not considered safe for | | | | caffeine. Some of the oils from the coffee |
| human consumption. | | | | bean are removed as well, making it less |
| | | | flavorful. |
| Today there are 3 commonly used methods | | | | |
| available for removing caffeine from coffee, | | | | The Hypercritical Carbon Dioxide Method: |
| with dozens of variations of those methods. | | | | |
| Two common variations are Direct and Indirect | | | | In this method, which is not as popular as |
| Method. | | | | the other methods, the beans are soaked in a |
| | | | solution of liquid carbon dioxide to remove |
| European or Traditional Process - Direct | | | | the caffeine. The get to a liquid state, the |
| Method: | | | | carbon dioxide must be highly pressurized (73 |
| | | | to 300 atmospheres), which makes the logistic |
| The direct process involves softening the | | | | cost of this method a bit higher than the |
| beans by steam first, then washing them for | | | | other methods. After the caffeine is absorbed |
| about 10 hours with either a methylene | | | | by the carbon dioxide, either the pressure is |
| chloride or ethyl acetate solution to absorb | | | | reduced and carbon dioxide is allowed to |
| the caffeine from the bean. The solution is | | | | evaporate, or the solution is run through a |
| discarded, the beans are re-steamed to remove | | | | carbon filter to remove the caffeine. |
| any remaining solvent (methylene chloride | | | | Although more expensive, the advantage of the |
| boils away at 114° ethyl acetate at | | | | Carbon Dioxide Method is that since carbon |
| 104°), then the beans are dried to their | | | | dioxide is not a harmful gas, the method is |
| original moisture content. | | | | not harmful to health or the environment. |
| | | | |
| European or Traditional Process - Indirect | | | | Other Methods: |
| Method: | | | | |
| | | | Since there's no consensus best-way to remove |
| Instead of being steamed, the coffee beans | | | | caffeine from coffee beans, there are still |
| are soaked in very hot water, which extracts | | | | new methods being developed. |
| the caffeine along with many of the oils. | | | | |
| This solution is then treated with either | | | | One new method is the Triglyceride Process. |
| methylene chloride or ethyl acetate, which | | | | In this method, green coffee beans are soaked |
| bonds with the caffeine. Then the solution is | | | | in a solution or hot water and coffee to draw |
| heated to the temperature at which the | | | | the caffeine to the surface of the beans. |
| caffeine and either methylene chloride or | | | | Then, the beans are transferred to another |
| ethyl acetate compounds evaporate. The oils | | | | container and immersed in coffee flavor oils |
| are then reintroduced to the beans, and the | | | | that were obtained from spent coffee grounds. |
| beans are then dried. | | | | The flavor oils contain triglycerides are a |
| | | | naturally-occurring combination of fatty |
| About 80% of decaf coffees are processed by | | | | acids and glycerol, and, after several hours |
| the Traditional, or European Process, and | | | | at high temperatures, they are able to remove |
| many serious coffee drinkers believe this | | | | the caffeine from the beans while not |
| method makes for the best-tasting coffee. | | | | affecting the flavor. |
| Others worry about the chemicals involved. | | | | |
| Methylene chloride is considered a superior | | | | Another new method, and possibly the future |
| solvent since it can evaporate at a lower | | | | of decaffeinated coffee, is the cultivation |
| temperature and leaves virtually no trace in | | | | of Naturally Caffeine-Free Coffee from trees |
| the beans, but it is an environmental hazard | | | | that have recently discovered in that produce |
| to workers at decaffeination plants, and it | | | | coffee with no caffeine. Depending on the |
| is known to harm the ozone layer. Ethyl | | | | variety of coffee, the caffeine content |
| acetate can be extracted from various fruits | | | | already varies significantly, from about 75 |
| and vegetables and so it is considered a | | | | mg to 250 mg per 6 oz. cup. Arabica coffee |
| "naturally-found" chemical, but most ethyl | | | | varieties normally contain about half the |
| acetate used for decaffeinating is | | | | caffeine of robusta varieties, and dark roast |
| synthethically produced. | | | | coffee usually has less caffeine than lighter |
| | | | roasts since the roasting process reduces |
| The Water or Swiss Water Process: | | | | caffeine content of the bean. An arabica bean |
| | | | containing a tenth as much caffeine as a |
| Also known as the water process, this process | | | | normal bean has been found, so the |
| uses no chemicals, but rather hot water, | | | | possibility of developing or finding a bean |
| steam and osmosis to remove the caffeine from | | | | with no caffeine is probably a matter of |
| the coffee in two steps. In the first step, | | | | time. |