Decaffeination
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 normally contains about half the caffeine of Coffea robusta. The solvent is then drained away and the beans steamed for an additional 10 hours to remove any residual solvent.When all the caffeine and coffee solids are released into the water, the beans are discarded. 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). Almost all brands of decaffeinated coffee still contain some caffeine. The need to remove caffeine could vanish if coffee growers begin using a naturally caffeine-free bean first produced in June 2004. .
These beans are removed and dried, and thus retain most if not all of their flavour and smell. Although the process originated in Switzerland in the 1930s, today the world s only Swiss Water decaffeination facility is based near Vancouver, British Columbia, Canada. In the direct method, the coffee beans are first steamed for 30 minutes and then repeatedly rinsed with either methylene chloride (Dichloromethane/DCM) or ethyl acetate for about 10 hours. Due to health concerns regarding benzene, this process is no longer used commercially and Coffee Hag and Sanka are produced using a different process. The Swiss Water Process is a method of decaffeinating coffee beans developed by the Swiss Water Decaffeinated Coffee Company.
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 standard of having the beans 99.9% caffeine-free by mass. 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.
An equilibrium is reached after several cycles, where the water and the beans have a similar composition except for the caffeine. Coffee decaffeinated this way was sold as Kaffee HAG after the company name Kaffee Handels-Aktien-Gesellschaft (Coffee Trading Company) in most of Europe, as Café Sanka in France and later as Sanka brand coffee in the U.S.
They are then rinsed with a solvent that contains as much of the chemical composition of coffee as possible without also containing the caffeine in a soluble form. Café HAG and Sanka are now worldwide brands of Kraft Foods.
A Coffea arabica bean containing little caffeine was discovered in Ethiopia in 2004. The first commercially successful decaffeination process was invented by Ludwig Roselius and Karl Wimmer in 1903. 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 filters to remove the caffeine.
The process is usually performed on unroasted (green) beans, and starts with steaming of the beans. As in other methods, the caffeine can then be separated from the organic solvent by simple evaporation.
The beans are separated from the oils and dried. The same water is recycled through this two-step process with new batches of beans.
The caffeine is removed from the oils, which are reused to decaffeinate another batch of beans. The process repeats, filtering out all the caffeine until the beans are 99.9% caffeine-free.
The carbon dioxide is then used on another batch of beans. Then the beans are removed and either methylene chloride or ethyl acetate is used to extract the caffeine from the water.
This is a direct contact method of decaffeination. Tea may also be decaffeinated, usually by using processes analogous to the Direct Method or the CO2 process as described above. (While caffeine-free soft drinks are occasionally referred to as decaffeinated, some are better termed uncaffeinated : prepared via simply omitting caffeine from production.) In the case of coffee, various methods can be used.
After this point, the caffeine is the only material removed from the beans, so no coffee strength or other flavorings are lost. This process has the advantage that it avoids the use of potentially harmful solvents. Green coffee beans are soaked in a hot water/coffee solution to draw the caffeine to the surface of the beans.
It involved steaming coffee beans with a brine (salt water) solution and then using benzene as a solvent to remove the caffeine. 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. This process is technically known as supercritical fluid extraction.
Pre-steamed beans are soaked in a bath of supercritical carbon dioxide at a pressure of 73 to 300 atmospheres. Since the flavor-charged water cannot remove any of the coffee solids from the new beans, only the caffeine is released.
Decaffeination is the act of removing caffeine from coffee beans, mate, cocoa, tea leaves and other caffeine-containing materials. The water then passes through a carbon filter that traps caffeine but lets the coffee solids pass through.
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. 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.
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. In the indirect method, beans are first soaked in hot water for several hours, in essence, making a strong pot of coffee. To decaffeinate the coffee bean by the Swiss Water method, a batch of green (unroasted) beans is soaked in hot water, releasing caffeine.
The resulting solution, called flavor-charged water by the company, is then put in a similar filtration device, and new coffee beans are added. Camellia sinensis assamica) may differ in natural caffeine content.
Younger leaves and buds contain more caffeine per weight than older leaves and stems. This liquid works better than water because it is kept in supercritical state near the transition from liquid to gas, combining favorable diffusivity properties of the gas with increased density of a liquid.
