Ever wondered what the fuss about decaf is? Here are six commonly asked questions about decaf that we’ve answered for you.
What is Decaffeination?
The process of removing the caffeine substance from green coffee beans prior to roasting.
How much caffeine is in a typical cup of coffee?
This depends on the type of coffee bean, the darkness of the roast, and the brewing process.
There are two primary types of bean: arabica and robusta. Arabica beans, on the whole, contain less caffeine than robusta, which is why it tastes softer and sweeter. The current market is comprised of 75-80 per cent arabica and 20-25 per cent robusta; cafes generally prefer arabica coffees, while robustas tend to be used in instant brands.
Coffea arabica - Scot Nelson, Flickr
Coffee robusta - Dennis Tang, Flickr
The roasting process also burns away some of the caffeine content in the bean, so darker roasts will have less caffeine compared to lighter roasts. The difference is only very slight, but it is worth noting the next time you’re after a caffeine hit.
A shot of espresso (30mL) using arabica beans contains an average of 80 to 100mg of caffeine. A cup of drip coffee, or filtered coffee (120mL) contains approximately 100 to 125mg.
Roasted regular vs Roasted decaf - Origins Roasters, Flickr
How is coffee decaffeinated?
There are four main decaffeination processes: direct, indirect, carbon dioxide, and natural.
1. Direct Green coffee beans are first steamed until softened, and then rinsed with solvents to remove the caffeine. After draining, the beans are steamed again until all residual solvents are removed. This process typically uses either dichloromethane or synthetic ethyl acetate.
2. Indirect Also called the two-step process, the beans are first soaked in hot water, and then discarded. The solvents are run through the remaining water to extract the caffeine, and that same water is run through a new batch of beans. Because the water is essentially a large pot of coffee, the new batch of beans will not lose any of its flavour, only the caffeine.
3. Carbon dioxide Carbon dioxide in its supercritical form falls between a liquid and gaseous state, and this is used as the solvent to extract caffeine from green coffee beans soaking in water. The caffeine is extracted from the carbon dioxide using charcoal filters, and the carbon dioxide is pumped back into a pressurised container for reuse. This process is costly, and only used for decaffeination in bulk, with commercial-grade coffees.
4. SWISS Water method This method relies on solubility and osmosis to extract caffeine. The green beans are first soaked in hot water to extract and dissolve the caffeine; the hot water is passed through a charcoal filter to capture the caffeine molecules. What remains is a green coffee extract, in which a fresh batch of green beans is soaked to remove the caffeine, and repeated until 99.9 per cent of the caffeine content has been extracted. This is similar to the indirect method, but without the use of solvents.
Foodi Fact: Recently, a naturally decaffeinated strand of the Coffea arabica plant was discovered in Ethiopia. It contains only 0.76mgs of caffeine per gram, compared to the 12mg in the regular arabica plant, due to a genetic deficiency. It has been trademarked in Brazil and termed ‘Decaffito’.
How much caffeine remains in a cup of decaf?
US guidelines require a coffee to have no less than 97.5 per cent of its caffeine content removed in order to be considered decaffeinated. This approximates to between 2 to 6mg of caffeine per cup. Internationally, the accepted standard is 99.9 per cent.
However, no matter which process is used to extract caffeine from the beans, it is difficult to claim results that are 100 per cent caffeine-free, as there is always the possibility of finding residual caffeine in a coffee.
Are there any benefits to drinking decaf over regular coffee?
The idea that decaffeinated coffee is healthier than regular coffee is debatable. Aside from the reduced amount of caffeine, there isn’t actually much difference between the two. Certainly those who are allergic to caffeine will benefit greatly from its removal; others have reported feeling less side effects commonly associated with caffeine, such as jitteriness, headaches, and anxiety, but this varies from person to person. In short, there has been no conclusive scientific evidence to say that decaf is better than regular coffee.
There were concerns that coffees decaffeinated using solvents may have potential negative effects on health, but these have been debunked — roasting the beans burns away any residual solvents from the decaffeination process.