HOW do you fancy a tall, chewy latte? Coffee is regularly contaminated with unappetising detritus ranging from floor sweepings and twigs to poisonous, mouldy coffee beans.
In an admission likely to have coffee lovers gagging on their macchiato or spluttering on their cappuccino, the international body responsible for coffee quality has admitted that ground and instant varieties often contain unexpected ingredients.
Despite the introduction of rules designed to reduce the amount of unwanted debris in coffee, poisonous beans, twigs, stones, floor sweepings and "other bits and pieces" are still found in coffee sold in Britain, according to Dr Euan Paul of the British Coffee Association.
"We have had major concerns with coffee imported into Europe that has been marketed under the name of coffee but doesn’t deserve to be," said Paul.
He explained most of the rogue objects accumulated in the coffee production would be turned into sugars during the roasting process and would not cause any harm to drinkers. However, Paul added that in some cases they were seriously diluting the amount of coffee in the jars, packets and cups bought by shoppers and coffee shop customers.
He said that some cheaper varieties might contain just 20% coffee, which he believes should prevent manufacturers being able to sell it as such.
"You might find only 20% of coffee in a lower quality sample... which prevents you being able to call it coffee," he said.
Commenting on the mouldy beans, which can contain toxins, Paul said: "On the tree the bean can be attacked by insects that make holes in the bean. In the drying process beans can get broken, and not all beans ripen at the same time."
The guidelines designed to tackle the contamination problem were introduced by the International Coffee Council in October last year.
They lay down minimum standards for exportable coffee. Under the rules, firms should not export Arabica coffee that contains more than 86 ‘defects’ per 300gms, or Robusta coffee that contains more than 150 imperfections in 300gms.
Arabica coffee is grown on high ground, and is suited to espressos and ground coffee. Robusta coffee grows on lower levels and is more bitter. Instant coffee is made principally from Robusta beans.
Pablo Dubois, head of operations at the International Coffee Organisation said: "This figure has been based on many years of trading experience. It is far from being arbitrary. Coffee is like wine, you need to pick it and process it before selling it."
Under the complex grading process, points are awarded to every 300gms of coffee imported into the UK. Each ‘defect’ is weighted differently, with a ‘black bean’ scoring seven points, and a twig scoring more.
Dubois said the contaminants were "more a question of inert matter that dulls flavour than a health risk".
However, he added there was a small theoretical risk of mouldy coffee beans being toxic. "There is occasionally the possibility that mouldy beans can have low level micro-toxin occurrence," he said.
As well as supposedly improving the quality of coffee, it was hoped that the guidelines would help cut the surplus on the world market by eliminating lower grade varieties.
Paul said he expected to see an overproduction of 15 million bags on the world market this year. "It’s purely a system to try and remove approximately 5% of the world’s supply of coffee by keeping this lower grade of coffee away."
Paul said shoppers were getting what they paid for and people buying 2 cups in high street coffee shops were far less likely to come across contaminated coffee than those buying cut-price varieties in supermarkets.
He added the guidelines had already reduced the amount of contaminated coffee, that makes up "only a very small percentage of the market".
Britain’s multi-million pound coffee culture is fast catching up with the nation’s staple cup of tea. According to the most recent report by the market analysis firm A C Nielson, coffee marginally outsold tea in the UK, with around 156 million cups being drunk every day.