TCQ science: Specialty Decaf

In 2014 a friend approached me and told me she loves the smell of coffee but she has a caffeine allergy. At that point I supported the “death before decaf” wave. However I started looking into it and realized there are a lot of techniques to decaffeinate.

In my experience there were not many people putting a lot of thought into their decaf coffee, also the coffee that is used for decaffeinating is not often an enjoyable product. During the next year’s research I realized there are a lot of opportunities. There are many ways a decaf can be pleasant. Let me explain  what I have found out in the past to get to the current specialty decaf The Coffee Quest works with. Keep in mind this is an abbreviated version made easier to understand. For full info on how the techniques work, get in touch and I will be able to give more in-depth information. 

Decaffeinating coffee can be done a lot of different ways, however there are 4 main techniques. All are about full immersion in a bath of some sort of liquid.

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

Before coffee gets decaffeinated all beans need to be opened first. 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 cannot open the beans. Therefore the right amount of water and steam is necessary for good decaffeination.

1.) DCM is a well-scalable technique. This means DCM is usually for decaffeinating large batches of coffee. Because of the size of the batch, more can be decaffeinated at once and the cost price per kg is  less. Therefore you can see DCM applied to cheaper beans. The disadvantage of efficiency and large scale, it is not profitable (if even possible) to decaffeinate small quantities of coffee. This excludes a lot of higher quality lots that are traceable to farmers.

DCM is not a product you want to find in your coffee therefore it needs to be flushed properly. When flushing the coffee, other chemically created products are added to the beans to bind to the DCM and pull away from the coffee. When all DCM is finally flushed with water and dried back to the original humidity.

2.) E.A. is a volatile product with a sweet chemical scent just like nail polish remover. Next to its volatile scent, it is also highly inflammable, making it important to apply the right precautions. Companies working with E.A. should have safe equipment to ensure any danger will be minimized. EA works the same way as DCM and because of its need for more Machinery, companies need to enlarge the batch size to keep costs lower. Also it is more difficult to find a company willing to decaffeinate smaller lots. 

Because of the possibility for ethanol to be extracted from fermented sugar cane, some people also call it sugar cane technique decaf.

3.) Swiss water is the name of a Canadian company that brews a saturated “soup” of the compounds of green coffee. First, they add green coffee to a vat of warm water and let it circulate for a while. All of the water will circulate the beans and pass a carbon filter, back to the coffee and this will continue. The carbon filter only takes out the Caffeine but leaves all other compounds in the “soup”. When all the soluble compounds are in the water the green beans are thrown out and a green coffee soup remains. This “soup” is the liquid Swiss water decaffeinated in. 

The soaked green beans that need to be decaffeinated, are immersed in the liquid and continue the same circulation as the previous coffee did. The only difference is that now the water has already taken compounds from the previous coffee. Soluble compounds only move from one cell to another when it finds a place of lower saturation in a liquid. When it finds an equilibrium, soluble compounds do not move and stay in the cell. Now the water is already saturated with green coffee so the liquid doesn’t extract the soluble compounds out of the green bean. Meanwhile, the caffeine will 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.) The Liquid CO2 is the technique that the Coffee Quest decided to use. Carbonized water is extracted from wells in the south of Germany. This water is naturally carbonized by being in contact with carbonate minerals for thousands of years. The water is being pressed down by limestone or dolomite, pressurizing it and adding carbonite to the water. These waters you can find in the supermarket for example: Perrier or Bru.

The water is pumped up to the surface and there the water is 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 and all other compounds remain.

The liquid circulates past the beans picking up all the caffeine, moving towards a tank at the end of the process. In this tank, the saturated CO2 drops the caffeine and the CO2 is reintroduced to the beans. This process repeats 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 is perfect to use as a natural additive to sodas or natural energy drinks.

As explained earlier, it’s not just about a better technique of decaffeinating, more important is the quality of the product you put in the liquid to decaffeinate. Bad quality green beans from old crops are often used for decaffeination, but when you start with an unpleasant coffee, the process is not going to enhance that flavor. In July The Coffee Quest sent a shipment of type 1 Colombia from Huila to our partner in Germany for decaffeination. 

After checking all different styles of decaffeinating the choice fell on CO2 decaffeination. The loss of flavour is less and the process is 

From now on we are able to provide the exact same coffee with and without caffeine. With this coffee I would like to show that it is possible to produce high quality decaf, pleasant to drink at any time. With this even caffeine allergic or high sensitive people are able to drink specialty coffee.

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