FREE next working day delivery on orders over £15

Decaf Coffee: How is Coffee Decaffeinated?

Mozzo Coffee | 23 October, 2023

 

In the world of specialty coffee, the quality of coffee goes beyond its caffeine content. It’s rooted in the intricacies of the entire coffee journey and ritual – from harvesting to roasting and the final brew in your cup. While everyone’s reasons for choosing decaf might be different, decaf coffee has been growing in popularity.

So we wanted to take a closer look at the decaffeination process. How is coffee decaffeinated and what are the different methods used to remove caffeine from the coffee beans? Let’s dive in. 

What really is decaf coffee?

Decaf coffee is essentially your regular coffee, but with a lower caffeine content. And contrary to popular belief, decaf coffee is not 100% caffeine-free. While different decaffeination processes remove between 97-99.9% of the caffeine from the coffee beans, they don’t remove it completely. That’s why all decaf coffees retain a little bit of caffeine in them with the final amount of caffeine dependent on different roasting and brewing methods

What really is caffeine? 

A mild stimulant for our brain and nervous system, if you’ve ever experienced the caffeine shakes you’ll know the effects from one too many. Caffeine is a naturally occurring substance found in coffee and other plants and foods, and the amount of caffeine in your coffee very much depends on the bean, roast, grind and your brewing method. In a standard cup, coffee can contain anywhere from 70 to 200 mg of caffeine, whereas a typical cup of decaf coffee contains about 2 to 15 mg of caffeine. 

How was decaf discovered? 

The first commercially successful decaf coffee dates back to the early 20th century, when a shipment of coffee beans fell into the sea and lost their caffeine but kept their flavour. This observation inspired the German coffee merchant, Ludwig Roselius, to create the first decaf method in 1903 called the Roselius process. It involved steaming coffee beans with various acids and using a solvent to pull out the caffeine. While this particular process is no longer used today due to health reasons, it marked a significant milestone in the development of decaffeinated coffee production today. 

How to ditch the caffeine

Regardless of the decaffeination method used, each process is done at the pre-roasting stage when coffee is still green. Since caffeine is one of the components which gives coffee its bitter, acidic flavour, the true challenge in decaffeination isn’t so much about removing the caffeine as it is about preserving the other elements that contribute to coffee’s flavour, quality and complexity. 

There are many ways to remove caffeine from coffee, but the most common processes are chemical solvent, water and C02 processes. 

The solvent method

The solvent method can be divided into two groups: direct solvent process and indirect solvent process. The direct solvent method is the oldest and most commonly used process. In this process, the beans are soaked directly in a solvent such as methylene chloride in order to remove caffeine from the bean. The indirect-solvent process is a bit different, since the solvent itself does not come into contact with the coffee beans. First, the beans are soaked in hot water to remove the caffeine, then the caffeine bean-water is treated with the solvent to remove the remaining caffeine in a separate tank, so the solvent never touches the beans. 

Sugarcane or Ethyl Acetate 

This is another solvent method, and in this method green coffee is steamed under low pressure to prepare for immersion in Ethyl Acetate (EA), which is a solvent derived from decomposing fruits like bananas, a byproduct of sugar production or synthetically created from petroleum-based sources. Once the coffee is saturated, the tank is emptied and a fresh EA solution is introduced, continuing for an additional 8 hours. In the final step the coffee is steamed removing most of the EA. This method is believed to give decaf coffee a slightly sweeter taste. 

The Swiss Water Process 

Here at Mozzo, our decaf coffee is decaffeinated using The Swiss Water process. This method is an organic and 100% chemical free option for decaffeinating coffee beans and that’s why we love it. The result is a truly delicious, chemical-free decaf coffee, making you doubt it’s even decaf. This process relies on Green Coffee Extract (GCE), a solution packed with all the water-soluble natural compounds found in green coffee just minus the caffeine. 

Here’s how it works: 

  • Green coffee is cleaned and pre-soaked using water from mountains of British Columbia, preparing beans for the target moisture level that’s ideal for the caffeine extraction process. This step also removes first, durst and silverskin 
  • Caffeine molecules move out of the coffee beans and into the GCE through osmosis
  • GCE is constantly circulated around the green coffee for 8-10 hours until there is no more than 0.1% of caffeine remaining in the green coffee. 
  • Caffeine is removed from the GCE through a proprietary carbon filter system
  • The carbon is sent to a regeneration furnace to burn away the caffeine so that it can be reused for the next batch

CO2 Processing 

This is a fairly recent decaffeination method introduced by Kurt Zosel from the Max Planck Institute and Experts. Instead of using chemical solvents, this method uses liquid CO2 (carbon dioxide) to extract the caffeine. The process starts by placing water-soaked coffee beans in a container known as an extraction vessel. The liquid CO2 is forced into the container at a really high pressure, where the CO2 extracts the caffeine by dissolving it. The caffeine-rich C02 is then transferred into a different chamber, where the pressure is released turning the CO2 back into the gas. 

Over to you 

You should never skip flavour when you want to skip caffeine, that’s why we have chosen the Swiss Water process. We believe that it is the best organic decaffeination process for retaining the unique characteristic of the coffee, something that chemical processes can’t achieve. From decafcoffee pods, decaf coffee bags, decaf filter coffee  and espresso, explore our decaf collection if you want to venture into decaf speciality coffee that doesn’t compromise on flavour.