How Healthy is Decaffeinated Coffee?

Solvent vs Swiss Water & C02 Decaffeination

Thinking of switching to decaffeinated coffee but unsure if decaf is a better choice? Consider the various processes used, before you abandon the hard stuff.

In a 2009 Food Reviews International article"Current Trends in Producing Low Levels of Caffeine in Coffee Berry and Processed Coffee Powder," Vinod Kumar and G.A Ravishankar describe the four commercial methods used to produce decaffeinated coffee. All involve soaking or steaming the unroasted green bean to extract all compounds, and then mixing this solution with solvents or filtering.

Methylene Chloride to Remove Caffeine

Methylene chloride is a colourless liquid with a mild, sweet odour. Often found in paint stripper, aerosol and pesticide products, it is also used in the manufacture of photographic film.

This solvent is highly effective in selectively removing caffeine with minimal loss of taste and aroma. Methylene chloride evaporates at 40 degrees Celsius and coffee is roasted at 230 degrees Celsius so most coffee has less than 0.1 parts per million residual methylene chloride. Still, a worrying amount to risk consuming.

Chemical Ethyl Acetate as Alternative Caffeine Solvent

Ethyl acetate is another solvent found naturally in some fruits. However, due to cost implications of using naturally extracted Ethyl Acetate, a manufactured chemical is often used. Ethyl Acetate is used as a solvent in oil-based lacquers and enamels (especially in polyurethane finishes) and in inks and adhesives. It is also used as a solvent in many chemical processes. The treatment method is essentially the same as the methylene chloride process.

Direct and Indirect Decaffeination Techniques

There are both direct and indirect methods of applying these solvents. In the most direct technique, the green unroasted bean is steamed in a rotating drum for 30 minutes to soften it and is then rinsed with the solvent. Savour that aroma! The caffeine-loaded solvent is then drained away and the beans are re-steamed, eliminating all but trace amounts of the remaining solvent. The beans are then dried by air or vacuum and roasted to remove remaining traces of solvent.

The indirect method soaks the unroasted bean in a solution of near boiling water and coffee to draw out the caffeine. The caffeine/water mixture is then drained away and treated with solvent, absorbing the caffeine. This mixture is then heated, evaporating the solvent. The remaining mixture is reabsorbed by the beans without the solvent touching them.

Swiss Water Process

Because of health concerns the above processes are used much less frequently, paving the way for the process developed by the Swiss Water Decaffeinated Coffee Company and the Carbon Dioxide method of decaffeination.

In the Swiss Water Process, named after the country in which the process was originally pioneered, the water and coffee solution extracted from the beans is passed through charcoal or carbon filters gently removing 99.9% of the caffeine while leaving the flavour intact. No chemicals are used. Higher costs associated with this process make it an unattractive option to coffee manufacturers.

Carbon Dioxide Decaffeination

The CO2 method applies the CO2 at high pressure so that it behaves as a liquid, penetrating the bean to extract the caffeine. This results in removal of 97% of the caffeine and as the beans return to room pressure the CO2 remaining on the beans dissipates as gas.

Still not sure the possible side effects of these four methods are less detrimental than caffeinated coffee? Well, perhaps your next cup of decaf will come from a naturally decaffeinated coffee plant discovered in Ethiopia in 2004. Whatever you buy, read the labels, and demand SwissWater process decaf in your favourite coffeehouse. The price of a good cup of decaf joe must be measured in more than dollars.