Decaf coffee is in every way the same as its caffeinated counterpart except for one thing; caffeine.
Caffeine is well known for its stimulant effects and is the primary reason some people drink coffee. Luckily for these people, research has shown caffeine to have a positive impact on mood, reaction time, memory and mental function, metabolic rate, and athletic performance. However, for some, the stimulating effects of caffeine can be too much to manage and opting for decaf is a safer option for everyone involved.
In order to be called ‘decaf’, coffee beans need to be at least 97% free of caffeine, which may mean that there are still a handful of the grounds floating around in the bottom of your cup. Beware!
Despite lacking one important ingredient, decaffeinated coffee is still loaded with the antioxidants that make coffee beans the single biggest source of antioxidants in the Western diet. The difference in antioxidant content between decaf and caffeinated coffee is due to the method chosen to decaffeinate the beans. There are a number of different ways to remove caffeine from coffee beans, using combinations of water, solvents or carbon dioxide.
Historically, solvents have been used to extract caffeine from beans. While the common solvents used are typically naturally occurring compounds found in unripened fruit, they are costly to extract in suitable quantities, so were synthetically produced in labs, all of a sudden making them feel less ‘natural’.
Luckily for us, the first solvents used for these processes have been labelled as carcinogenic by the WHO and are no longer used.
Direct-solvent based processes, coffee beans are:
- Steamed to open pores – 30mins
- Rinsed repeatedly in solvent to remove caffeine – 10hrs
- Steamed again to remove residual solvent.
Indirect processes, coffee beans are:
- Soaked in near-boiling water (extracting caffeine and other flavour elements and oils from the beans) – 3+ hours
- Rinsed repeatedly in solvent to selectively bond to the caffeine – 10hrs
- Heat treated to evaporate the solvent and caffeine
- Reintroduced to the first water to re-absorb oils and flavour compounds lost through initial process.
Typically, if a process is not named for your decaf coffee or beans, you can assume it has been treated using one of these solvent-based methods.
Non-solvent based process
The Swiss Water Process is an innovative, chemical free process that was pioneered in Switzerland in 1933 and is now a widely used commercial decaf method. Instead of chemical caffeine extraction, this process relies on two natural concepts: solubility and osmosis (Biology 101, anyone?).
- Beans are batch soaked in hot water to dissolve the caffeine
- This water is drawn off and passed through an activated charcoal filter (a common water filtering method that removes contaminants and impurities from water, including caffeine)
- Two tanks are left: one with beans without caffeine or flavour, the other with flavour-charged water (“Green Coffee Extract”).
- Here’s where the clever thinking comes in: The flavourless caffeine-free beans are discarded and the flavour-rich water is then reused to remove the caffeine from a new batch of coffee beans. Because this water is already saturated with flavour from the last beans, the flavours in the new batch can’t dissolve so remain in the decaffeinated beans.
- Voila – decaffeination without loss of flavour.
Haven’t we come a long way from the cancer-causing decaffeination processes of the past to the clean, green water-based processes of today?!
For your highly-strung friends, Swiss Water Decaf is the perfect way to enjoy coffee without the side-effects of too much caffeine.
Words by Emily Rust from Shaky Isles