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Dr. Nicholas Leadbeater, University of Connecticut - Decaffeinating Coffee

http://stream.publicbroadcasting.net/production/mp3/wamc/local-wamc-981511.mp3

Albany, NY – In today's Academic Minute, Nicholas Leadbeater of the University of Connecticut explains the chemical process used to remove caffeine from coffee, and where all that caffeine ends up.

Nicholas Leadbeater is an associate professor of organic and inorganic chemistry at the University of Connecticut, where he heads the New Synthetic Methods Group. Leadbeater and the NSMG research cleaner and more efficient methods for creating synthetic materials. Dr. Leadbeater holds a Ph.D. from Cambridge University, where he was a research fellow until 1999.

About Dr. Leadbeater

Dr. Nicholas Leadbeater - Decaffeinating Coffee

I enjoy my triple shot of espresso to start the day. As well as tasting good, the caffeine in it gives me a boost to get going. But I also want to be able to enjoy the taste of coffee in the evening and still be able to sleep afterwards. So I turn a product first produced in the early 1900's - decaffeinated coffee.

Back then, removing the caffeine involved steaming coffee beans with a salt water solution and then using a solvent called benzene to remove the caffeine. Since coffee contains over 400 chemicals important to the taste and aroma of the final drink: it is really challenging to remove only caffeine while leaving the other chemicals at their original concentrations.

After the discovery that benzene can cause cancer, attention turned to other ways of removing the caffeine. A modern alternative is to use supercritical carbon dioxide. A supercritical fluid has both the gaseous property of being able to penetrate anything, and the liquid property of being able to dissolve things. At elevated pressures, carbon dioxide is in its supercritical state, and it dissolves the small caffeine molecules, allowing them to be extracted. Since flavor molecules are larger, they remain intact, which means the coffee retains its flavor much better.

But what to do with all that caffeine that is collected? Well, much of it ends up in soft drinks. Less than 5% of the caffeine found in cola drinks actually comes from the kola nut and the caffeine in many popular "high caffeine" beverages comes primarily, and sometimes completely, from the addition of caffeine extracted from decaffeination.

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