Decaffeinating green coffee beans is a fascinating process with several methods designed to remove caffeine while preserving flavour. Here are the most popular techniques:
CO₂ Processing
This method immerses green coffee beans in warm, pressurised water, causing them to expand and become more porous. Carbon dioxide is then introduced, binding with the caffeine molecules. The water and CO₂ are removed, and the beans are dried.
What makes this method appealing is that it preserves the coffee's natural flavour—none of the carbohydrates or proteins responsible for taste are extracted. The process is eco-friendly too; the by-products are recycled, with water filtered and reused. However, the downside is that this method can be expensive due to the sheer amount of CO₂ required for commercial use.
Sugarcane (Ethyl Acetate) Processing
Sometimes called "natural decaffeination," this process starts with steaming the coffee beans to open their pores. They’re then rinsed in ethyl acetate—a compound that binds to caffeine molecules—effectively removing caffeine. Ethyl acetate can be naturally derived from sugarcane, making this process seem more “natural,” but commercial-scale production often requires synthetic ethyl acetate.
While it’s effective, this method can subtly change the coffee’s flavour profile, adding a fruity note that some might find appealing, while others prefer a purer flavour.
Swiss Water Method
The Swiss Water Method is a chemical-free, organically certified process centred on Green Coffee Extract (GCE). Green coffee beans are soaked in hot water to dissolve the caffeine. To ensure flavour isn’t lost, this water is passed through a charcoal filter that traps only the caffeine molecules while retaining the sugars, oils, and minerals.
The resulting GCE is used to soak new batches of beans, removing caffeine while leaving flavour compounds intact. The Swiss Water Method is praised for being environmentally friendly, maintaining the coffee's original taste, and producing minimal waste.
To find out more about decaf processes, visit our blog post ‘Definitive Guide for Roasting Decaf Coffee’.