DECAFE COFFEE: HOW DO YOU TAKE THE CAFFEINE OUT OF THE COFFEE?

Ever wondered what cool sciencey stuff they are teaching undergraduates at the University of Queensland?

 Every school day I will post my newly learned cool fact... Enjoy

04/03/2013

CHEMISTRY

DECAFE COFFEE: HOW DO YOU TAKE THE CAFFEINE OUT OF THE COFFEE?

I don’t know about you guys, but in the morning when I wake up I really enjoy a coffee.

I do like the flavour of a nice coffee and I can appreciate the difference between a well extracted espresso and a gritty bitter one. However, I am fairly confident in saying that I am searching for the caffeine hit.

Coffee was probably first drunk in Africa and the first truly credible evidence for its cultivation comes from Yemen, and seems to have spread around the world from there.

People quickly came to appreciate the effect that caffeine intake has on a human metabolism and today, coffee is one of the most commonly drunk beverages in the world.

It is the primary agricultural industry in twelve countries and the trade of unroasted coffee is the 7^th largest agricultural export on the planet.

Heaven knows why, but for some reason there is a market for coffee drinkers who are not looking for the caffeine ‘high’, but still enjoy the taste and/or perhaps the experience of sitting in a coffee house with friends.

So... How do we get that caffeine out of those beans?

Coffee has over 400 chemicals within it that directly affect the taste, so science had to find a way to get the coffee beans to stay exactly the same yet have the caffeine removed.

This is where the chemistry comes into play.

 

It has to do with solutes and solvents.

A solute is a type of chemical that will dissolve in a solvent.

A solvent is a type of chemical that will allow a solute to be dissolved within it.

A good example is salt dissolving into water. The salt is a solute and the water is a solvent.

What happens technically is that the salt molecules are more attracted to the water molecules than they are to each other, so the crystalline solid structure of the salt crystls breaks up and floats away into the water mix.

 

To get the caffeine out of the coffee beans, scientists ‘wash’ the unroasted beans in special types of solvents that bind to the caffeine and not to anything else.

To find this perfection in such a complex entity as a plant seed, is a testament to how badly people wanted decaffeinated coffee.

Some of the methods companies have used are incredibly complex. Such as saturating the solvents used with any compounds that are removed other than the caffeine, or using carbon dioxide compressed upwards of 300 atmospheres.

These are just generalisations of the processes used.

Thinking of doing some decaf yourself?

Try calling the companies that do this and see if they will tell you exactly how they extract caffeine.

This information is a multi-billion dollar trade secret…