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How do you decaffeinate coffee?

Decaff Coffee - test tes 

Do you know about how coffee is decaffinated?

Let’s begin by stating the obvious. Caffeine occurs in coffee naturally, so any method of decaffeination (no matter how good it is) is considered by many aficionados unnatural. Some go even so far as claiming that it goes against the natural order of things. Yet there are about 10% of coffee lovers who would like to enjoy a good cup of coffee without the mild stimulating affect of caffeine.

Can it be done? Can you really have a GOOD cup of coffee that has been subjected to a decaffeination process? Read on and make up your own mind whether it’s possible.

CAVEAT EMPTOR: “decaffeinated” does not mean 100% caffeine free. In fact a decaf coffee only needs to be 97% caffeine free according to the USDA. That means that an average 12 oz. cup of decaffeinated coffee, which originally might have been packed with 180 mg of caffeine, now only would contain 5.4 mg of caffeine.

 
The Roselius Process

The first commercially successful decaffeination process was invented by the German coffee merchant Ludwig Roselius in 1903 and patented in 1906. Legend has it that his quest for decaffeinated coffee was motivated by the belief that excessive coffee drinking had poisoned his father.

The “Roslius Process” involved steaming coffee beans with a brine solution (i.e., water, saturated with salt) and then using the organic chemical compound benzene as a solvent to extract the caffeine. This process, however, is no longer used due to the fact that benzene is known to be a human carcinogen.

The Four Main Methods of Decaffeination Used Today
1) The Indirect–Solvent Based Process

In the indirect-solvent method the coffee beans are soaked in near boiling water for several hours, which extracts the caffeine as well as other flavor elements and oils from the beans.

The water is then separated and transferred to another tank where the beans are washed for about 10 hours with either methylene chloride or ethyl acetate. The molecules of the chemical solvent selectively bond with the molecules of caffeine and the resulting mixture is then heated to evaporate the solvent and caffeine.

Lastly, the beans are reintroduced to the liquid to reabsorb most of the coffee oils and flavor elements.

This method is very popular in Europe, especially in Germany, and primarily uses methylene chloride as solvent. Hence it’s often referred to as “KVW Method” (short for: Kaffee Veredelugs Werk), “The European Method”, “Methylene Chloride Method”, or “Euro Prep”.

2) The Direct–Solvent Based Process

In this method of decaffeination the beans are steamed for about 30 minutes in order to open their pores. Once the coffee beans are receptive to a solvent, they are repeatedly rinsed with either methylene chloride or ethyl acetate for about 10 hours to remove the caffeine. The caffeine-laden solvent is then drained away and the beans are steamed again to remove any residual solvent.

Most of the time the solvent of choice in this method is ethyl acetate, so you’ll often see it referred to as “The Natural Decaffeination Method” or “The Ethyl Acetate Method”.

Typically, if a process is not named for a decaffeinated coffee, it has been treated by either the direct or indirect solvent methods.

3) The Swiss Water Process (SWP)

AKA: SWP Method, Swiss Water Process, Activated Charcoal Decaffeination, Dihydro-oxide Process

The History

This chemical-free water decaffeination process was 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 finally introduced to the market and its facility is based near Vancouver, British Columbia, Canada.

Note that the Swiss Water Company’s decaffeination facility is the only facility in the world certified organic by both OCIA and Aurora Certified Organic. In addition, they are also certified Kosher by the Kosher Overseers Association.

A Short Explanation of SWP

This particular method of decaffeination is different from what we’ve so far seen in that it does not directly or indirectly add chemicals to extract the caffeine. Rather, it relies entirely on two concepts, namely solubility and osmosis, to decaffeinate coffee beans.

It begins by soaking a batch of beans in very hot water in order to dissolve the caffeine. The water is then drawn off and passed through an activated charcoal filter. The porosity of this filter is sized to only capture larger caffeine molecules, while allowing smaller oil and flavor molecules to pass through it.

Consequently we end up with beans with no caffeine and no flavor in one tank, and caffeine-free “flavor charged” water (aka “Green Coffee Extract”) in another tank.

And here’s where the magic happens. The flavorless caffeine-free beans are discarded, but the flavor rich water is reused to remove the caffeine from a fresh batch of coffee beans.

Since this water already is saturated with flavor ingredients the flavors in this fresh batch can’t dissolve; only caffeine moves from the coffee beans to the water. So the result is decaffeination without a massive loss of flavor.

Coffees decaffeinated by this method are always labeled as “SWISS WATER” Decaf.

This method is almost exclusively used for decaffeination of organic coffee.

Coffee decaffeinated using the environment-friendly Swiss Water Process undergoes regular caffeine level audits to ensure compliance to 99.9% caffeine-free.

4) CO2 process

AKA: CO2 (or Carbon Dioxide ) Method, Liquid Carbon Dioxide Method, Supercritical Carbon Dioxide Method

The Carbon Dioxide (CO2) Method is the most recent method. It was developed by Kurt Zosel, a scientist of the Max Plank Institute, and uses liquid CO2 in place of chemical solvents. It acts selectively on the caffeine, i.e., it releases the alkaloid and nothing else.

In the CO2 decaffeination process, water soaked coffee beans are placed in a stainless steel container called the extraction vessel. The extractor is then sealed and liquid CO2 is forced into the coffee at pressures of 1,000 pounds per square inch 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. Here the pressure is released and the CO2 returns to its gaseous state, leaving the caffeine behind. The caffeine free CO2 gas is pumped back into a pressurized container for reuse.

Because of its cost, this process is primarily used to decaffeinate large quantities of commercial-grade, less-exotic coffee found in grocery stores.

Why is it so Difficult to Make Good Decaf Coffee?

Let’s start by stating a sad fact first: finding a good decaf coffee is the exception rather than the norm. The reason for this centers around two problems that are very difficult to overcome.

First, as we’ve already seen, the decaffeination process tends to damage many flavor compounds that contribute to the sensory character of roasted coffee.

Secondly, decaf coffees are notoriously difficult to roast. The reason for this is that decaffeinated, unroasted coffee beans start off almost brown in color rather than green. This makes it difficult for the roasters to control them, since they respond inconsistently and exaggeratedly to heat applied to them during roasting. Furthermore, they have less bound moisture content, which causes them to roast faster. So, you dealing with an unroasted “green” bean that tends to roast darker and faster than un-decaffeinated beans.

But all is not lost. Given what we just learned we can use this information to ensure a better decaf experience. Overall the type of roast you buy is going to have more of an impact on the taste than the decaf method. Try to avoid any decaf coffees that are really dark and oily, for you certainly don’t want to add the ravages of a very dark roast to the rigors of any decaffeination process.

 

Released On 16th Oct 2015

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