DECAFFEINATION is the removal of caffeine from coffee beans , cocoa , tea leaves, and other caffeine-containing materials. While soft drinks which do not use caffeine as an ingredient are sometimes described as "decaffeinated", they are better termed "non-caffeinated" because decaffeinated implies that there was caffeine present at one point in time. Decaffeinated drinks contain typically 1–2% of the original caffeine content, and sometimes as much as 20%. Decaffeinated products are commonly termed DECAF.
* 1 History
* 2.1 Common characteristics of decaffeination * 2.2 Swiss Water process
* 2.3 Organic solvent processes
* 2.3.1 Solvents used in decaffeination * 2.3.2 Direct method * 2.3.3 Indirect method
* 2.4 CO2 process * 2.5 Triglyceride process
* 3 Decaffeinated coffee
* 4 Decaffito * 5 Decaffeinated tea * 6 See also * 7 References
Friedlieb Ferdinand Runge performed the first isolation of pure caffeine from coffee beans in 1820. He did this after the poet Goethe requested he perform an analysis on coffee beans after seeing his work on belladonna extract. Though Runge was able to isolate the compound, he did not learn much about the chemistry of caffeine itself, nor did he seek to use the process commercially to produce decaffeinated coffee.
The first commercially successful decaffeination process was invented
by German merchant
Ludwig Roselius and co-workers in 1903 and patented
in 1906. In 1903, Ludwig accidentally stumbled upon this method when
his freight of coffee beans was soaked in sea water and lost much of
its caffeine without losing much taste. This original decaffeination
process involved steaming coffee beans with various acids or bases ,
then using benzene as a solvent to remove the caffeine. Coffee
decaffeinated this way was sold as Kaffee HAG after the company name
Kaffee Handels-Aktien-Gesellschaft (
Since its inception, methods of decaffeination similar to those first developed by Roselius have continued to dominate. While Roselius used benzene, many different solvents have since been tried after learning of the potential harmful effects of benzene. The most prevalent solvents used to date are dichloromethane and ethylacetate.
Another variation of Roselius' method is the indirect organic solvent method. This is very similar to the process described above, only instead of treating the beans directly, water resulting from the soaking of beans is treated with solvents and the process goes on until equilibrium is reached without caffeine in the beans. This method was first mentioned in 1941, and people have made great efforts to make the process more "natural" and a true water-based process by finding ways to process the caffeine out of the water in ways that circumvents the use of organic solvents.
Another process, known as the Swiss Water Method, uses solely water
and osmosis to decaffeinate beans. The use of water as the solvent to
decaffeinate coffee was originally pioneered in Switzerland in 1933
and developed as a commercially viable method of decaffeination by
Coffex S.A. in 1980. In 1988, the Swiss Water Method was introduced
by The Swiss Water Decaffeinated
Most recently, food scientists have turned to supercritical carbon dioxide as a means of decaffeination. Developed by Kurt Zosel, a scientist of the Max Planck Institute, it uses CO2, heated and pressurized above its critical point , to extract caffeine and could be useful going forward because it circumvents the use of other solvents and their possible effects entirely.
DECAFFEINATION PROCESSES FOR COFFEE
In the case of coffee, various methods can be used. The process is performed on unroasted (green) beans and starts with steaming of the beans. They are then rinsed with a solvent that extracts the caffeine while leaving other constituents largely unaffected. The process is repeated from 8 to 12 times until the caffeine content meets the required standard (97% of caffeine removed according to the US standard, or 99.9% caffeine-free by mass per the EU standard).
COMMON CHARACTERISTICS OF DECAFFEINATION
In all decaffeination processes, coffee is always decaffeinated in its green, unroasted state. The greatest challenge to the decaffeination process is to try to separate only the caffeine from the coffee beans while leaving the other chemicals such as sucrose, cellulose, proteins, citric acid, tartaric acid, and formic acid at their original concentrations. This is not an easy task considering coffee contains somewhere around 1,000 chemicals that contribute to the taste and aroma. Since caffeine is a polar, water-soluble substance, water is used in all forms of decaffeination. However, water alone is not the best solution for decaffeination because it is not a selective solvent and therefore removes other soluble substances, including sugars and proteins, as well as caffeine. Therefore, most decaffeination processes use a decaffeinating agent such as methylene chloride , activated charcoal, CO2, or ethyl acetate. These agents help speed up the process and minimize the “washed-out” effects that water alone might have on the taste of decaffeinated coffee.
SWISS WATER PROCESS
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The Swiss Water® Process does not directly or indirectly add chemicals to extract caffeine. Rather, it relies entirely on two concepts – solubility and osmosis – to decaffeinate coffee beans.
The Swiss Water® Process uses Green
Once the GCE is rich with caffeine it is then percolated through carbon absorbers which attract the caffeine molecule from the GCE while leaving other green coffee elements intact in the GCE. When the GCE is once again lean of caffeine it is then used to remove additional caffeine from the green coffee. This is a continuous batch process that take 8-10 hours to meet the final residual decaffeinated target, which is 99.9% caffeine free by mass.
ORGANIC SOLVENT PROCESSES
Solvents Used In Decaffeination
Given numerous health scares connected to early efforts in
decaffeination using solvents such as benzene , trichloroethylene ,
and chloroform , the solvents of choice have become dichloromethane
and ethyl acetate .
In the direct method, the coffee beans are first steamed for 30 minutes to open their pores and then repeatedly rinsed with either dichloromethane or ethyl acetate for about 10 hours to remove the caffeine. The caffeine-laden solvent is then drained away and the beans steamed to remove residual solvent.
In the indirect method, beans are first soaked in hot water for several hours, in essence making a strong pot of coffee. Then the beans are removed and either dichloromethane or ethyl acetate is used to extract the caffeine from the water. As in other methods, the caffeine can then be separated from the organic solvent by simple evaporation. The same water is recycled through this two-step process with new batches of beans. An equilibrium is reached after several cycles, wherein the water and the beans have a similar composition except for the caffeine. After this point, the caffeine is the only material removed from the beans, so no coffee strength or other flavorings are lost. Because water is used in the initial phase of this process, indirect method decaffeination is sometimes referred to as "water-processed".
This process has been referred to as CO2 Method, Liquid Carbon Dioxide Method, and Supercritical Carbon Dioxide method but it is technically known as supercritical fluid extraction .
The supercritical CO2 acts selectively on the caffeine, releasing the alkaloid and nothing else. Water-soaked coffee beans are placed in an extraction vessel. The extractor is then sealed and supercritical CO2 is forced into the coffee at pressures of 1,000 pounds per square inch (about 69 bar) to extract the caffeine. The CO2 acts as the solvent to dissolve and draw the caffeine from the coffee beans, leaving the larger-molecule flavor components behind. The caffeine-laden CO2 is then transferred to another container called the absorption chamber where the pressure is released and the CO2 returns to its gaseous state and evaporates, leaving the caffeine behind. The caffeine is removed from the CO2 using charcoal filters, and the caffeine free CO2 is pumped back into a pressurized container for reuse on another batch of beans. This process has the advantage that it avoids the use of potentially harmful substances. Because of its cost, this process is primarily used to decaffeinate large quantities of commercial-grade, less-exotic coffee found in grocery stores.
Green coffee beans are soaked in a hot water/coffee solution to draw the caffeine to the surface of the beans. Next, the beans are transferred to another container and immersed in coffee oils that were obtained from spent coffee grounds and left to soak.
After several hours of high temperatures, the triglycerides in the oils remove the caffeine, but not the flavor elements, from the beans. The beans are separated from the oils and dried. The caffeine is removed from the oils, which are reused to decaffeinate another batch of beans. This is a direct-contact method of decaffeination.
CAFFEINE CONTENT OF COFFEE
CAFFEINE CONTENT OF DECAFFEINATED COFFEE
To ensure product quality, manufacturers are required to test the
newly decaffeinated coffee beans to make sure that caffeine
concentration is relatively low (no less than 97% caffeine content
reduction according to
A controlled study of ten samples of prepared decaffeinated coffee
from coffee shops showed that some caffeine remained. Fourteen to
twenty cups of such decaffeinated coffee would contain as much
caffeine as one cup of regular coffee. The 16-ounce (473-ml) cups of
coffee samples contained caffeine in the range of 8.6 mg to 13.9 mg.
In another study of popular brands of decaf coffees, the caffeine
content varied from 3 mg to 32 mg. An 8-ounce (237-ml) cup of regular
coffee contains 95–200 mg of caffeine, and a 12-ounce
(355-milliliter) serving of
Both of these studies tested the caffeine content of store-brewed coffee, suggesting that the caffeine may be residual from the normal coffee served rather than poorly decaffeinated coffee.
As of 2009, progress toward growing coffee beans that do not contain caffeine was still continuing. The term "Decaffito" has been coined to describe this type of decaffeinated coffee, and trademarked in Brazil.
The prospect for Decaffito-type coffees was shown by the discovery of
the naturally caffeine-free
Further information: Health effects of tea
In addition to CO2 process extraction, tea may be also decaffeinated using a hot water treatment. Optimal conditions are met by controlling water temperature, extraction time, and ratio of leaf to water, where higher temperatures at or over 100 °C, moderate extraction time of 3 minutes, and a 1:20 water to leaf weight per volume ratio removed 83% caffeine content and preserved 95% of total catechins . Catechins , a type of flavanol , contribute to the flavor of the tea and also, interestingly, have been shown to increase suppression of mutagens that may lead to cancer.
Both coffee and tea have tannins , which is responsible for the astringent taste, but tea has nearly three times smaller tannin content than coffee. Thus, decaffeination of tea requires more care to maintain tannin content than decaffeination of coffee in order to preserve this flavor. Preserving tannins is desirable not only because of their flavor, but also because they have been shown to have anticarcinogenic, antimutagenic, antioxidative, and antimicrobrial properties. Specifically, tannins accelerate blood clotting, reduce blood pressure, decrease the serum lipid level, produce liver necrosis, and modulate immunoresponses.
Certain processes during normal production might help to decrease the
caffeine content directly, or simply lower the rate at which it is
released throughout each infusion. Several instances in China where
this is evident is in many cooked pu-erh teas , as well as more
A generally accepted statistic is that a cup of normal black (often called red in China; as distinct from green) tea contains 40–50 mg of caffeine, roughly half the content of a cup of coffee.
Although a common technique of discarding a short (30- to 60-second) steep is believed to much reduce caffeine content of a subsequent brew at the cost of some loss of flavor, research suggests that a five-minute steep yields up to 70% of the caffeine, and a second steep has one-third the caffeine of the first (about 23% of the total caffeine in the leaves).
* Technology portal
* ^ A B C "Study: Decaf coffee is not caffeine-free". October 15,
2006. Retrieved 2008-01-12.
* ^ Weinberg, Bennett Alan; Bealer, Bonnie K. (2001). The World of
Caffeine: The Science and Culture of the World's Most Popular Drug.
Psychology Press. ISBN 9780415927222 .
* ^ A B C D E F G H I J K L M Emden, Lorenzo. "