Decaffeinated Coffee
Reiko Piekarski, Director of Coffee Programs | Fortuna Enterprises, LLC
For many, the morning routine of having freshly brewed coffee is a means to getting the day started. The aromatics wafting from the maker combined with the first sips are enough to awaken any sleepy soul. But what about those who yearn for the ritual but cannot participate because of the caffeine? Sadly, decaffeinated coffee has been cast under the shadow of regular coffee and consumers unfortunately suffer for the decisions, or lack thereof, of quality for the decaffeinated bean. It is time to shine some light on decaf coffee and emerge with a more inclusive and open perspective of this coffee processing method.
History
The Germans were well known for their fascination with coffee and it should come as no surprise that a method for extracting the caffeine would be invented by a German. Ludwig Roselius was a coffee merchant who is now known for the first commercially successful decaffeination process in 1903. What is named the Roseilus Process was later patented in 1906. Ludwig’s motivation cannot be confirmed but his quest for decaffeinated coffee was supposedly sparked by the belief that his father was poisoned due to excessive consumption of the caffeinated beverage. This pioneering method involved steaming the coffee seeds with a brine solution then using an organic chemical compound as a solvent to extract the caffeine. This process however is no longer in use as the benzene solution being used to extract the caffeine is known to be a carcinogen and harmful to the human body.
Conventional Solvent Process
The Roseilus Process paved the way for decaffeination methods that are commonly used today. In fact, roughly 70% of decaffeinated coffee undergoes the solvent process. The most commonly-applied solutions are methylene chloride and ethyl acetate. The first stage involves soaking or steaming the green coffee seeds to swell and increase in size. This exposes more surface area to allow optimal absorption of the solvent. The water is then separated from the moisture tank and the beans are transferred to a separate tank, where the coffee is then washed with either of the above mentioned solutions. These two solvents selectively bond to caffeine molecules drawing it, along with some coffee oils and flavor, out of the beans. The mixture is then heated to evaporate the solvent and caffeine. Finally, the green coffee is reintroduced to the liquid to reabsorb most of the extracted coffee oils and flavor components. The green decaffeinated coffee is then dried and shipped off to roasters.
Swiss Water and Mountain Water
Some more familiar methods out in the market today are Swiss or Mountain water. The Swiss Water Process decaffeination method was developed in Switzerland in 1933 using a chemical-free solvent solution. However, this method was not finally approved till 1988 where it was introduced to the market. This facility is based in Burnaby, British Columbia and is the only one in the world that is certified organic as well as Kosher. First, fresh clean water is combined in a tank along with a large quantity of green coffee and heated to make the “Green Coffee Extract” or GCE. The GCE is composed of flavor and caffeine to be further processed. The spent beans are discarded and the resulting extract passes through a proprietary carbon filtration system to remove caffeine. This solution is now ready to be reused to remove caffeine without removing the flavor components in future batches. The GCE is checked for quality before each reuse to maintain the standard as a marker for when a new GCE solution needs to be prepared. Check out the Swiss Water process animation here to see how it all works.
Descamex is a
mountain water processing facility located in Mexico. This similar water
process involves a solution which is not loaded with caffeine but other
components which limit the loss of flavor in the percolation period. The
solution can also be stripped of the caffeine extracted from previous batches
to be reset and reused to extract from a new batch. With both methods
harnessing the physics of solubility and osmosis the water process is able to
successfully decaffeinate coffee and also produce crude caffeine. What
about the extracted caffeine?. The crude caffeine is refined and
sold off to soda and pharmaceutical companies among other things.
Super-Critical Carbon Dioxide
One of the more recently developed methods of decaffeination is
the use of liquid carbon dioxide or otherwise recognized as CO2 Process. A
scientist of the Max Planck Society by the
name of Hurt Zosel developed the process utilizing the solvent based format but
replacing the chemicals with liquid CO2. What is
unique to this method is how CO2 acts
selectively to caffeine and not the key flavor components.
Green coffee is first soaked in a stainless steel extraction
chamber. Once the vessel is sealed the liquid CO2 is forced
into coffee under tremendous pressure in order to extract the caffeine. As the
solvent in this process, the CO2 dissolves
and draws out the caffeine while leaving the key flavor components behind. The
CO2, loaded with caffeine, is transferred to the absorption chamber
where the pressure is released allowing the CO2 to
return to its gaseous state leaving the extracted caffeine behind. Finally, the
caffeine-free CO2 gas is fed back into the pressurized container for reuse.
Since this process is so costly, it is primarily used to decaffeinate larger
quantities of coffee.
Growing Decaf Coffee
Sometime back in 1987, the Instituto Agronomico de Campinas (IAC) began
researching coffee trees for low levels of caffeine. After analyzing over 3,000
coffee trees, it was announced in 2004 that there were three identified plants. These
three plants were all from an Ethiopian variety presenting the naturally low
levels of caffeine. With this discovery, there was a movement for researchers in
Brazil to create a naturally stable and commercially available, caffeine-free
coffee. Ethiopia also started to screen for natural, caffeine-free varieties but
due to the lack of infrastructure and expertise the project was
discontinued.
It is important to note, the process of removing the caffeine from coffee seeds is not a natural procedure as the presence of caffeine in the coffee plant is part of the pest defense mechanism; with the exception of the coffee borer beetle. Too much caffeine consumption can pose health issues and at extreme levels can be lethally toxic. Decaffeinated coffee should not be shunted to poorer quality and thus associated with a negative experience. Coffee drinkers and roasters alike should take the time to learn more about what method is applied in order to make more conscious and sustainable decisions. Decaf coffee has its own place in the coffee world and it should be given the appropriate recognition but more importantly the same care as the regular counterparts.
Resources
Coffee Confidential:
Decaffeination
Sciencing: How to Extract
Pure Caffeine from Coffee
A Reference Guide to
Ethiopian Coffee Varieties
Naturally caffeine free coffee plant
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