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Decaffeination

Decaffeination

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Decaffeination is the act of removing caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

 from coffee beans
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...

, cocoa, tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

 leaves and other caffeine-containing materials. (While caffeine-free soft drink
Soft drink
A soft drink is a non-alcoholic beverage that typically contains water , a sweetener, and a flavoring agent...

s are occasionally referred to as "decaffeinated", some are better termed "uncaffeinated": prepared without adding caffeine during production.) Despite removal of caffeine, many decaffeinated drinks still have around 1-2% of the original caffeine remaining in them.

In the case of coffee, 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 extracts the caffeine while leaving the other essential chemicals in the coffee beans. 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
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 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: It is, therefore, challenging to remove only caffeine while leaving the other chemicals at their original concentrations.

Coffea arabica
Coffea arabica
Coffea arabica is a species of Coffea originally indigenous to the mountains of Yemen in the Arabian Peninsula, hence its name, and also from the southwestern highlands of Ethiopia and southeastern Sudan. It is also known as the "coffee shrub of Arabia", "mountain coffee" or "arabica coffee"...

normally contains about half the caffeine of Coffea robusta. A Coffea arabica bean containing little caffeine was discovered in Ethiopia in 2004.

Roselius process


The first commercially successful decaffeination process was invented by Ludwig Roselius
Ludwig Roselius
Ludwig Roselius was a German coffee merchant and founder of the company KAFFEE HAG. He was born in Bremen and is credited with the development of commercial decaffeination of coffee...

 and Karl Wimmer in 1903. It involved steaming coffee beans with a brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...

 (salt water) solution and then using benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 as a solvent to remove the caffeine. Coffee decaffeinated this way was sold as Kaffee HAG
Café HAG
Café HAG is a worldwide brand of decaffeinated coffee owned by U.S. multinational Kraft Foods.The brand originated in Bremen in Germany in 1906 and took its name from the company title Kaffee Handels-Aktien-Gesellschaft, or Kaffee HAG for short....

 after the company name Kaffee Handels-Aktien-Gesellschaft (Coffee Trading Company) in most of Europe, as Café Sanka in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and later as Sanka
Sanka
Sanka is a brand of instant decaffeinated coffee, sold around the world, and was one of the earliest decaffeinated varieties. Sanka is distributed in the United States by Kraft Foods.-History:...

 brand coffee in the U.S
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Café HAG
Café HAG
Café HAG is a worldwide brand of decaffeinated coffee owned by U.S. multinational Kraft Foods.The brand originated in Bremen in Germany in 1906 and took its name from the company title Kaffee Handels-Aktien-Gesellschaft, or Kaffee HAG for short....

 and Sanka are now worldwide brands of Kraft Foods
Kraft Foods
Kraft Foods Inc. is an American confectionery, food and beverage conglomerate. It markets many brands in more than 170 countries. 12 of its brands annually earn more than $1 billion worldwide: Cadbury, Jacobs, Kraft, LU, Maxwell House, Milka, Nabisco, Oscar Mayer, Philadelphia, Trident, Tang...

. Due to health concerns regarding benzene, this process is no longer used commercially and Coffee Hag and Sanka are produced using a different process.

Swiss Water Process


The Swiss Water Process is a method of decaffeinating coffee beans developed by the Swiss Water Decaffeinated Coffee Company. To decaffeinate the coffee bean by the Swiss Water method, a batch of green (unroasted) beans is soaked in hot water, releasing caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

. When all the caffeine and coffee solids are released into the water, the beans are discarded. The water then passes through a carbon filter that traps caffeine but lets the coffee solids pass through. The resulting solution, called "green coffee extract (GCE)" by the company, is now available for decaffeinating coffee. 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 GCE passes through proprietary carbon, which captures the caffeine. The process repeats, filtering out all the caffeine until the beans are 99.9% caffeine-free. These beans are removed and dried, and thus retain most if not all of their flavor.

Although the process was pioneered in Switzerland in the 1930s, today the world's last major Swiss Water Process decaffeination facility is based near Vancouver
Vancouver
Vancouver is a coastal seaport city on the mainland of British Columbia, Canada. It is the hub of Greater Vancouver, which, with over 2.3 million residents, is the third most populous metropolitan area in the country,...

, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. However this process is simple enough to be used locally by many coffee roasters.

Direct method


In the direct method, the coffee beans are first steamed for 30 minutes and then repeatedly rinsed with either dichloromethane
Dichloromethane
Dichloromethane is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is miscible with many organic solvents...

 or ethyl acetate
Ethyl acetate
Ethyl acetate is the organic compound with the formula CH3COOCH2CH3. This colorless liquid has a characteristic sweet smell and is used in glues, nail polish removers, and cigarettes...

 for about 10 hours. The solvent is then drained away and the beans steamed for an additional 10 hours to remove residual solvent. Sometimes coffees that are decaffeinated using ethyl acetate are referred to as naturally processed because ethyl acetate can be derived from various fruits or vegetables; but, because of the impracticality of gathering natural ethyl acetate, the chemical used for decaffeination is synthetic.

Indirect method


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
Solubility equilibrium
Solubility equilibrium is a type of dynamic equilibrium. It exists when a chemical compound in the solid state is in chemical equilibrium with a solution of that compound. The solid may dissolve unchanged, with dissociation or with chemical reaction with another constituent of the solvent, such as...

 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, sometimes indirect method decaffeination is referred to as "water-processed" even though chemicals are used.

CO2 process


This process is technically known as supercritical fluid extraction
Supercritical fluid
A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. It can effuse through solids like a gas, and dissolve materials like a liquid...

. In the carbon dioxide method, the caffeine is dissolved from the beans by liquid carbon dioxide at high pressure. Pre-steamed beans are soaked in a bath of supercritical carbon dioxide
Supercritical carbon dioxide
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.Carbon dioxide usually behaves as a gas in air at STP or as a solid called dry ice when frozen...

 at a pressure of 73 to 300 atmospheres. After a thorough soaking for around ten hours, the pressure is reduced, allowing the CO2 to evaporate, or the pressurized CO2 is run through either water or charcoal
Charcoal
Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...

 filters to remove the caffeine. The carbon dioxide is then used on another batch of beans. This liquid works better than water because it is kept in supercritical
Supercritical fluid
A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. It can effuse through solids like a gas, and dissolve materials like a liquid...

 state near the transition from liquid to gas, combining favorable diffusivity
Diffusivity
Diffusivity can refer to:*Diffusivity of heat*Diffusivity of mass:** Molecular diffusivity ** Eddy diffusivity*Momentum diffusivity...

 properties of the gas with increased density
Vapour density
Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen....

 of a liquid. This process has the advantage that it avoids the use of potentially harmful substances.

Triglyceride process


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.

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.

Decaffeinated tea


Tea may also be decaffeinated, usually by using processes analogous to the Direct Method or the CO2 process, as described above. Fermentation (i.e., the process of oxidizing tea leaves to create "black," "white," or "oolong" tea leaves from green leaves) does not affect the amount of caffeine in the tea, though tea-plant species (i.e., Camellia sinensis sinensis vs. Camellia sinensis assamica) may differ in natural caffeine content. Younger leaves and buds contain more caffeine per weight than older leaves and stems. Also, certain processes during production might lend a hand in either decreasing the caffeine content directly or simply lowering the rate at which it is released throughout each infusion. Several instances in China where this is evident is in many cooked pu'er teas, as well as more heavily fired Wuyi Mountain oolongs; commonly referred to as 'zhonghuo' (mid-fired) or 'zuhuo' (high-fired). A generally accepted statistic is that a cup of 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 reduce caffeine content in a subsequent brew by 80–90%, 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).

Caffeine content of decaffeinated coffee


Almost all brands of decaffeinated coffee still contain a minimum amount of caffeine. Drinking five to ten cups of decaffeinated coffee could deliver as much caffeine as would one or two cups of regular coffee, according to research at the University of Florida Maples Center for Forensic Medicine. In one independent study of 10 popular decaffeinated coffees, researchers found that all but one contained detectable caffeine. The 16-ounce (473-milliliter) cups of coffee samples contained caffeine in the range of 8.6 milligrams to 13.9 milligrams. In another similar study of popular brands of decaf coffees, the caffeine content was anywhere from 3 milligrams up to 32 milligrams. 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.

Health effects of decaffeinated coffee


Consumption of decaffeinated appears to be as beneficial as caffeine-containing coffee with regard to all-cause mortality, according to a large prospective cohort study. In women, consumption of decaffeinated coffee significantly decreases all-cause mortality with an odds ratio
Odds ratio
The odds ratio is a measure of effect size, describing the strength of association or non-independence between two binary data values. It is used as a descriptive statistic, and plays an important role in logistic regression...

 of between approximately 0.8 to 0.9 with a consumption of 1 cup to approximately 6 cups per day, compared to those who drink less than one cup per month. In men, these beneficial effects are not as great, yet show a tendency toward significantly less mortality for those that drink more than 2 cups per day compared to those that drink less than one cup per month.

Decaffito


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 Coffea charrieriana, a Coffea arabica
Coffea arabica
Coffea arabica is a species of Coffea originally indigenous to the mountains of Yemen in the Arabian Peninsula, hence its name, and also from the southwestern highlands of Ethiopia and southeastern Sudan. It is also known as the "coffee shrub of Arabia", "mountain coffee" or "arabica coffee"...

plant, reported in 2004. It has a deficient caffeine synthase
Caffeine synthase
Caffeine synthase is a methyltransferase enzyme involved in the caffeine biosynthesis pathway. It is expressed in tea species, coffee species, and cocoa species...

 gene, leading it to accumulate theobromine
Theobromine
Theobromine , also known as xantheose, is a bitter alkaloid of the cacao plant, with the chemical formula C7H8N4O2. It is found in chocolate, as well as in a number of other foods, including the leaves of the tea plant, and the kola nut...

 instead of converting it to caffeine. Either this trait could be bred into other coffee plants by crossing them with C. charrieriana or an equivalent effect could be achieved by knocking out
Gene knockout
A gene knockout is a genetic technique in which one of an organism's genes is made inoperative . Also known as knockout organisms or simply knockouts, they are used in learning about a gene that has been sequenced, but which has an unknown or incompletely known function...

the gene for caffeine synthase in normal coffee plants.