Whilst some may think decaf is the best way to get your coffee fix without the added caffeine hit, like anything we consume, this all depends on where the product comes from and how it was processed.
Caffeine can be extracted from green coffee beans, simply by immersing them in water. Unfortunately, this process will also extract desirable oils, flavours and other solids from the bean resulting in less flavourful coffee. To overcome this problem, manufacturers will commonly use one of the following methods:
- Chemical Process #1 – Methylene Chloride
- Chemical Process #2 – Ethyl Acetate
- CO2 Process
- The Swiss Water Process
CHEMICAL PROCESS #1 – METHYLENE CHLORIDE (also called the European Process)
- Beans are soaked in near boiling water, extracting all of the caffeine, flavor and essential oils from the bean.
- The water is then separated from the beans into a separate tank. Here the water is treated with methylene chloride. Methylene chloride bonds to caffeine which makes it easier to remove from the water, leaving the essential flavours and oils behind.
- The original beans are then re-introduced to the remaining water, reabsorbing their flavor and oils that were originally eliminated.
More often than not, coffee lovers will usually pick decaffeinated blends that have been processed using this method based on the simple fact that it tastes better.
CHEMICAL PROCESS #2 – ETHYL ACETATE (also called Natural decaf)
- The coffee beans are first steamed for 30 minutes and then repeatedly rinsed with either dichloromethane or ethyl acetate for about 10 hours.
- The solvent is then drained away and the beans steamed for an additional 10 hours to remove residual solvent. This process removes the caffeine.
Sometimes coffees that are decaffeinated using ethyl acetate are referred to as “naturally processed” or “naturally decaffeinated” because ethyl acetate can be derived from various fruits or vegetables. HOWEVER, because of the impracticality of gathering natural ethyl acetate, the ethyl acetate used for decaffeination is usually synthetic. If in doubt, contact your manufacturer.
Pre-steamed beans are immersed in supercritical carbon dioxide (this is a liquid form of carbon dioxide – set between its gas form and solid form more commonly known as dry ice). This immersion takes places in a pressure chamber at 73 to 300 atmospheres. After a thorough soaking for around ten hours, the pressurised CO2 (containing the dissolved caffeine) is removed from the chamber which is returned to atmospheric pressure. The caffeine is removed from the CO2 using charcoal filters and the CO2 is recycled for use on another batch of beans.
THE SWISS WATER PROCESS
- Green beans are cleaned and hydrated with pure water preparing them for coffee extraction.
- Developers create a Green Coffee Extract (GCE) by soaking containers of Arabica coffee beans in water until the caffeine and other essential oils have been extracted into the water. The beans are removed and the residual water is then put through a carbon filter to capture the caffeine ONLY. What is left? GCE: water that is saturated with those all-important soluble coffee solids, oils and flavours, minus the caffeine.
- Cleaned and hydrated green coffee beans (step 1) are then placed in the GCE and left to soak under strict conditions (critical to the success of this process).
- The beans are then later filtered until beans are 99.9% caffeine free. This process takes 8 to 10 hours.
- After the beans are decaffeinated, they are removed from the holding tanks, dried, bagged, tagged, and ready to be roasted.This process is 100% chemical free, water decaffeination process.
From a quick Google search, the following companies (use the Swiss Water method to produce their decaffeinated coffee:
- Sensory Lab
- Campos Coffee
- Gloria Jeans
There are a number of other companies that use this process, google your favourite bean and search for decaf.
NOTE: Although many leading brands state they use a “natural water method” they do not necessarily use the Swiss Method, rather the CO2 method mentioned above. The Swiss Water Method is the most natural and chemical free process available, it is a great marketing tool and as such, if a company uses this method, they will clearly state it on their website and packaging. In my opinion, my research suggests that by describing their decaf method as the “natural water method”, these companies are using the CO2 method whilst wanting to jump on “Swiss Water Method” bandwagon.
All good baristas will know whether or not their decaf coffee is produced using the Swiss Water method, so if you are ever in doubt, just ask.
Don’t forget, coffee is a heavily sprayed crop, so drinking organic coffee will help reduce your exposure to toxic herbicides, pesticides, and fertilizers. If you want to go a step further, look for fair-trade certified coffee, which means the coffee farmers have been paid fairly and treated well.
All caffeine should be consumed in moderation 😉