Row brewing on method of caffeine removal from coffee

Guidelines show one cup of brewed coffee has 111mg of caffeine with 78mg in a cup of instant coffee. Picture: Alamy/PA

Should we be worried about drinking decaf coffee?

A row about the process for removing caffeine from coffee is brewing in America with environmental groups calling for one extraction substance to be banned due to cancer and health fears.

The substance, methylene chloride or dichloromethane, is also used in the EU although it has to be removed under regulations before the coffee is roasted as is also the case in America. 

The Environmental Defense Fund and four other groups petitioned the US Food and Drug Administration to ban this completely from the decaf process.

The colourless liquid has a wide range of uses including to extract pharmaceuticals such as vitamins or antibiotics as well as removing caffeine from unroasted coffee beans and tea leaves, according to the European Chlorinated Solvents Association.

It used to be allowed in paint stripper but has been banned in that format since a change in EU laws around 2010 linked to dangers associated with high levels of exposure through inhalation or skin contact.

The American environmentalists argued in their submission that the substance has been found to induce cancer in humans and animals and is not safe.

The Food Safety Authority of Ireland said, however, while this substance is used in the EU for decaf, strict EU regulations around its use in food ensure it “does not pose a risk”.

It is approved for use as an extraction solvent only under restrictions, said communications manager Jane Ryder.

“In accordance with good manufacturing practice, only residues of extraction solvents would be present in the final product ready for consumption and would therefore not pose a risk to the consumer,” she said.

Conditions of use are listed in the EU directive 2009/32/EC.

For methylene chloride used in decaffeination of coffee and tea, the maximum residue limits allowed to remain are 2mg/kg in roasted coffee and 5mg/kg in tea.

Various coffee companies describe the decaf process on their websites, indicating steam or water can be used to draw caffeine to the surface of beans.

Then an extraction substance is applied before the beans are steamed again, and then roasted. 

Both these processes remove the methylene chloride or other substances used, leaving trace amounts only, they say.

The FSAI also has advice on caffeine.

“Our advice is up to 400mg of caffeine per day raises no safety concerns for non-pregnant adults,” Ms Ryder said. "Pregnant women should consume no more than 200mg caffeine per day.” 

FSAI guidelines show one cup of brewed coffee has 111mg of caffeine with 78mg in a cup of instant coffee.

In contrast, a cup of decaf coffee has 4mg of caffeine. A cup of black tea has 44mg of caffeine and a herbal tea has none.

Groups such as women going through menopause, people with high stress levels, or those who are more sensitive to caffeine are sometimes also advised to limit caffeine intake. 

Cork Coffee Roasters CEO John Gowan said decaf is not as popular as coffee in its three shops or online store.

“We have decaf on the menu but hardly anyone buys it”, he said, saying people typically order caffeinated americanos, lattes, cappuccinos or hot chocolate instead.

“We sell hardly any of it, people come into our shops for coffee.” 

They also sell decaf coffee beans in 1kg bags online, but he said it is rarely ordered.

He prefers coffee himself, and said: “I don’t know anyone who drinks decaf, it’s not a common thing.” 

He was unsure why it is not more popular, saying: “We have decaf and organic green tea, but our main sales are Arabica coffee that we roast ourselves."