How is coffee decaffeinated - and is it any good?
Let's answer the first question - How do you decaffeinate coffee?
Well, the first thing to say is that all coffee grown will contain caffeine, although I'm sure someone somewhere is trying to work out a way to grow already decaffeinated beans, for the moment the coffee beans need to go through a process to remove the caffeine.
There are two main methods used to remove the caffeine from the beans, and these methods remove the caffeine at the the green bean stage i.e before they are roasted.
The two main methods commonly used are the Chemical Process, sometimes rather confusingly referred to as Naturally Decaffeinated, and the Swiss Water Process. Both of these methods will remove almost all the caffeine from the coffee beans and each method strives to retain as much of the coffee oils and flavourings as possible.
The Chemical Process
It's a bit complicated, but here goes...firstly, the beans are soaked in a vat of water - this removes the caffeine from the beans. Unfortunately this process also removes a lot of the flavourings and compounds that make the coffee taste like coffee - not good. So...the water solution containing the caffeine and coffee compounds is then drained off. Solvents are then added to this solution - typically methylene chloride or ethyl acetate and over a period of around ten hours the caffeine and the flavourings are separated The mixture is then heated to remove the solvents and the caffeine. What is left is a solution containing water and the coffee flavours and compounds. The beans are then reintroduced to this solution and will soak back up all or nearly all of the flavours that had initially been extracted - without the caffeine. Rather confusingly this process can often be referred to as Naturally Decaffeinated.
Adding chemicals to coffee doesn't sound great and many people are put off by it - the fact that methylene chloride can also be used as a paint stripper doesn't help! It has to be said though that the chemicals used and the process itself have all been passed safe and only neglible traces of solvents remain. That said, at Kata we only use the Swiss Water Process which we will come on to now.
The Swiss Water Process
This process uses no chemicals and is certified organic. The process again starts with the beans being soaked in water. This allows the pores of the beans to open up to allow the caffeine to be more easily extracted. The beans are then passed through water containing all the flavour and compounds that have been extracted from previous green beans - but crucially, with the caffeine removed. Whilst the beans are circulated in the solution caffeine is extracted, but as the water already contains all the other flavour compounds these do not dissolve and therefore remain in the green bean. The solution is then continually re-circulated through a carbon filter that removes only the caffeine. The process continues until 99.9% of all the caffeine is removed.
We believe that this process produces the best tasting and ethically sound decaf beans, which is why at KATA we only use Swiss Water Decaf.
So to the next question- Does Decaf Taste any Good?