Buying decaffeinated coffee beans explained.
December 16, 2019

Buying decaffeinated coffee beans explained.

Lots of people are quick to jump to the assumption that decaf coffee is inferior, and tastes nothing like ‘real’ coffee. As you read this you may also agree that decaf is totally different but we can bet the majority of people who say this either haven't actually tried a good decaf coffee or have only tried very few. It's just one of those conceptions that has been around for years.

To understand why decaf may taste different, we first need to understand what decaf coffee actually is. 


For a coffee to be called ‘Decaf’ needs to be 0.1% or less caffeine and not ‘caffeine-free’ as some may think. The average cup of coffee can vary from 80-200mg of caffeine depending on the type and amount of coffee used. Decaf coffee can acceptably have up to around 10mg of caffeine in a cup, again depending on the type and amount. To put all of this into perspective, a can of Coke contains 32mg of caffeine and a 100-gram bar of chocolate contains 20-40mg. 

Coffee does not grow naturally with low caffeine, so a manual process must take place.


Decaf coffee has been around commercially since shortly after a patent was registered in 1903, but the first records of anyone beginning to look into it date back to the early 1800’s. This began with Johann Wolfgang von Goethe (the author of the famous german play, ‘Goethe’s Faust’), and Friedlieb Ferdinand Runge who was a German chemist/scientist. 

Runge had made a very unique discovery as a teenager which involved a chemical found in nightshade, which when separated from the plant, could dilate pupils. This caught the attention of Goethe, who was also passionate about natural science. Gothe was very interested in the separation of natural properties, so much so that he invited Runge to demonstrate his discovery. Goethe was so impressed with the demonstration, that he gifted Runge a box of coffee beans (a delicacy someone else had given him) and hinted that he might want to experiment on them, which no doubt was Gothe’s ulterior motive. 

Runge went on to discover caffeine, one of the most consumed stimulants in the world. Whilst he had separated the caffeine from the coffee, the leftover coffee was in no state to be drunk, this remained the case for some years to come.

Fast forward back to 1903 when a German coffee merchant called Ludwig Roselius registered a patent for the process. The idea of doing this was however accidentally discovered. Roselius had a cargo delivered which had been spoiled by being soaked in seawater. Roselius understandably wanted to see if the cargo was salvageable, what he discovered was a taste which still resembled the original product, but without so much caffeine. He then went on to experiment with removing caffeine while retaining as much taste as possible. In 1906 he founded the company Cafe HAG where he sold the first decaffeinated coffee commercially.


Coffee is always decaffeinated raw as using any process will deteriorate the flavours too dramatically if decaffeinating after the beans have been roasted.

Ludwig Roselius who is mentioned above, soaked and steamed his coffee in various chemicals and eventually ended up using the solvent benzene to remove the caffeine from the raw coffee beans. Benzene was later classified as a human carcinogen and consumers moved away from products containing it. This marked the end of this method.  

The process has remained largely unchanged in recent years and some processes are still very similar to Roselius’s process. Many different solvents were tried over the years. The reason for using solvents is that soaking beans in water does remove the caffeine, however, water also removes lots of the flavours and oils from the beans. Because of this, methods to either reduce the soaking time or methods to re-introduce flavours are needed. We will get into this as the article goes on.

There are now four different methods which can be used to decaffeinate coffee, two of which still use (safe) solvents and the other two methods use non-solvent methods.

1) Direct solvent process 

Firstly the beans are steamed for a short while to prepare them for caffeine extraction. The beans are then washed with solvents such as methylene chloride (a very safe solvent) for many hours to remove to caffeine. The beans are then drained and steamed once more to remove any leftover solvents. 

2) Indirect solvent process

This process is where the beans are soaked in very warm water for many hours. The water is then drained and now solvents (such as methylene chloride again) are used to wash the beans to soak up the remaining caffeine. The beans are then heated, just enough for the caffeine (and solvent) to evaporate. At this point, the beans are now very low in caffeine, but also in taste, so finally the liquid is re-introduced to soak the beans once more, and give back some of the flavours.

3) The Swiss Water process - non-solvent 

The Swiss Water process is where the green beans are soaked in hot water to dissolve the caffeine, like the start of the indirect solvent method, however at this point the water is then filtered through a carbon filter made from active charcoal, this removes the caffeine but preserves a lot of the flavours.

Interestingly, the beans are then discarded and a new batch is again soaked, but in the caffeine-free water which was created from the first batch. So once again the water removes caffeine however this time much less flavour is removed since the water is already full of the original flavours and oils.

4) Sparkling Water (CO2) method - non-solvent

The final method is the newest process and regarded to be one of the best as it uses no chemicals and loses very little flavour. It is, however, the most expensive process to perform.

Water-soaked coffee beans are put in a sealed extraction chamber then liquid C02 is forced through the chamber at very high pressure, the C02 binds to the caffeine but does not bind to the flavour components (like how the filter in the Swiss Water method works). Due to the high pressure, it removes the caffeine extremely efficiently. The result is a very low soaking time and a coffee which will taste very similar to the original product. This is our preferred method.


The last thing to note is that coffee is not decaffeinated by the roaster the majority of the time due to the sheer expense, space and equipment needed to perform any of these methods. So regardless of the process used, there is still the roasting to be done which will have a significant impact on the flavour. Roasting decaffeinated coffee beans is also a lot more difficult as the beans have already been through a process and will respond differently to roasting. Luckily here at Spiller & Tait, we have the talent to roast decaffeinated coffee, we also have the passion for great coffee so we chose non-other than the Sparking Water (C02) method.

If you are in search of a great decaffeinated coffee or you still have your doubts about how great it can taste we would highly recommend giving ours a try here.

As always, we would recommend buying beans rather than ground coffee and grinding your beans just before you brew it.