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TCQ science: Flavour in the Beans, but no Caffeine

In 2014, a friend approached me and told me she loves the smell of coffee but has a caffeine allergy. At that point, I was supporting the “death before decaf” wave. However, after looking into this, I realized there are many techniques to decaffeinating coffee.
In my experience, not many people put extra thought into their decaf coffee. The chosen beans for decaffeination are not often enjoyable coffees. The year that followed, I started to realize there are quite some opportunities out there to create a pleasant decaf. My investigation showed me the way towards the specialty decaf we are now offering with The Coffee Quest.  

Let’s have a look! Keep in mind this is an abbreviated version to make it easier to understand.
Get in touch for more in-depth information about how each technique works. 

Decaffeinating can be done in many ways...all concern a full immersion in a bath of some sort of liquid. Here are the four main options.

  1. Di-Chloride methane (DCM)
  2. Ethyl Acetate (E.A.) – also called sugar cane technique
  3. Swiss water
  4. Liquid CO2

To start the decaffeination process, the coffee needs to be opened up. To achieve this the beans are soaked in water and steam. By applying too much water, mineral compounds would start migrating from the beans in the water, but too little water won’t open the beans. Therefore, the right amount of water and steam is necessary for good decaffeination.

1. Di-Chloride methane (DCM) is a well-scalable technique. This means DCM is usually for decaffeinating large batches of coffee. The size of the batch allows for a cost-effective decaffeination process, lowering the price per kg.  DCM is therefore applied on cheaper beans. However, the disadvantage is not providing a profitable outcome for decaffeinating small quantities of coffee. This excludes higher quality lots that come in smaller batches, but might have farm level traceability.

DCM is not something you want to find at the end product, so it needs to be flushed properly. When doing that, other chemical solutions are added to bind to the DCM and pull this away from the coffee. By doing this, traces of DCM are steamed away and the beans are dried back to the original humidity.

2. Ethyl Acetate (E.A.) is a volatile product with a sweet chemical scent similar to nail polish remover. The highly inflammable content requires the right safety precautions. Companies working with E.A. should have safety equipment to ensure any danger kept to a minimum. E.A. works in the same way as DCM in terms of economies of scale. Companies have the need for machinery to enlarge the batch size to lower the costs per kg. Good luck finding a company willing to decaffeinate smaller lots! 

The Ethanol (alcohol) that is part of E.A. is commonly extracted from fermented sugar cane. This is why Ethyl Acetate is often called the sugar cane technique.

3. Swiss Water is the name of the Canadian company that brews a saturated “soup” from the compounds of green coffee. Everything starts by adding green coffee to a vat of warm water. All of the water will twirl the beans and pass through a carbon filter, then back to the coffee and so on. The carbon filter only takes out the caffeine but leaves all other compounds in the liquid. After all the soluble compounds are in the water, the green beans are taken out. The remaining soup is the liquid Swiss water. 

The soaked green beans that need to be decaffeinated are immersed in the liquid and continue the same circulation as the previous coffee. The only difference is that the water has already taken compounds from the previous coffee. Soluble compounds only move from one cell to another when they find a place of lower saturation within a liquid. When there is an equilibrium, soluble compounds do not move and stay in the cell. The water is saturated with green coffee so the liquid doesn’t extract the soluble compounds out of the green bean. Meanwhile, the caffeine does get extracted into the soup and taken out by the carbon filter. The whole process takes up to 8 hours until the caffeine level is below 0,8% of its weight.

4. Liquid Carbon Dioxide (CO2) is the technique that The Coffee Quest has decided to use. Carbonized water is extracted from wells in the south of Germany. This water is naturally carbonized by being in contact with carbonated minerals for thousands of years. The water is being pressed down by limestone or dolomite, pressurizing it and adding carbonite to the water. You can easily find this water in the supermarket, for example: Perrier or Bru.

The water is pumped up to the surface and kept under pressure. The CO2 is separated from the water and by keeping it pressurised the CO2 remains liquid. This liquid CO2 is the bath in which the green beans will be decaffeinated. Unlike water, liquid CO2 is a very bad solvent, which now comes in handy. Only caffeine is extracted from beans while other compounds remain.

The liquid circulates past the beans picking up all the caffeine, moving towards a tank at the end of the process, where the saturated CO2 drops off the caffeine and the CO2 is reintroduced to the beans. This process is repeated until there is less than 0,08% of caffeine in the beans. The caffeine will be extracted from the system by dissolving it in water. This by-product is perfect to use as a natural additive for sodas or natural energy drinks.

We can see that decaffeination techniques are not the only relevant ingredient for a good Decaf. The quality of the product you put in the liquid baths also play an important role. Bad quality green beans from old crops are almost a standard in decaffeination. Starting with a low-quality coffee is questionable, as the process is not enhancing any flavours for you final cup of coffee

In July, The Coffee Quest successfully sent a shipment of Type 1 Colombia from Huila to our partner in Germany for decaffeination. After checking the different styles of decaffeinating the choice fell on CO2 decaffeination. The flavour profile loses some intensity, but it keeps all of the original flavours (scoring only a point less on the SCA scale).

A good result that indicates we are able to provide the exact same coffee, with and without caffeine. Good ingredients make it possible to produce high-quality decaf, enyoyable to drink at any time. Even with a caffeine allergy or high sensitivity, people are able to drink specialty coffee.

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