Swiss method is a complex, expensive, but at the same time the most environmentally friendly way to decaffeinate coffee.
First, coffee makers prepare Green Coffee Extract, GCE. To do this, the first batch of coffee is soaked in water. So, all substances, including caffeine, gradually pass from the beans into the water. The extract is then filtered through a carbon filter system. Due to the fact that the caffeine molecules are the largest, they are retained in the filter. So, the flavoring substances pass through the filter and remain in the extract. The result is an extract that is rich in flavoring elements of the coffee bean, but does not contain caffeine.
Then, the next batch of beans is soaked in the prepared extract. When the bean enters the extract, its substances begin to strive for balance. Due to the fact that both the beans and the extract have the same amount of flavoring substances, they do not go anywhere. Because there is caffeine in the bean and not in the extract, it passes from the bean into the extract. As a result, the caffeine from the beans is transferred to the extract to restore balance. At the same time, the flavor and aroma elements remain in them.
But it is not possible to remove all the caffeine from the beans in one steeping. To solve it, after soaking, the extract is filtered from caffeine through carbon filters again. The beans are then soaked in the extract several times until caffeine content equals 0.01%.
However, it is cheaper to use solvents for decaffeination, that’s why such coffee costs less. Coffee that has been decaffeinated using the Swiss method is more expensive. However, its taste and quality is better.