How is Coffee Decaffeinated?

When you think about decaf coffee, have you ever wondered: How is coffee decaffeinated? 

A Brief History...

At the turn of the 20th century, commercially viable methods for removing caffeine from coffee started appearing in the patent record, pioneered by coffee merchants in Germany. A team from the company “Kaffee Hag,” led by Ludwig Roselius, applied for a patent in 1906 on a method that involved steaming coffee with saltwater to expand the bean so caffeine could be removed using a variety of solvents. They eventually settled on benzene. The original “Roselius Process” is no longer used because benzene, it turns out, is not good for humans. But the idea underlying the process, which was discovered by accident when some green coffee was soaked in salt water, is still fundamental to most decaffeination. No surprise there since caffeine is water-soluble, but so are other important components in coffee, like the things that make us enjoy it, and therein lies the rub … or the scrub, as it were.  

Four years after the Roselius Process received its patent, a U.S. patent was granted to another inventor from Germany named Ludwig for a method that is still in use. In 1910, Ludwig Seisser received a patent for ethyl acetate decaffeination. The patent application for ethyl acetate decaffeination describes what remains ideal for removing caffeine from coffee.

“For many reasons, it is desirable to obtain coffee beans somewhat less rich in caffeine than the natural coffee, but otherwise having substantially the properties of such natural coffee. This involves some form of extraction with a solvent that will remove the caffeine without affecting the other constituents of the coffee to any great extent.”

Another inventor from Germany, Heinrich Trillich, also received a patent in 1910 for an ethyl acetate decaffeination process that was apparently different enough in its mechanics to stand apart from the Seisser method.

The first thing to understand about ethyl acetate decaffeination or any other decaffeination process, is that decaffeinated does not mean the coffee is 100% free of caffeine. The FDA threshold for labeling a coffee decaffeinated is 97%, which means a 12 oz cup of decaffeinated coffee will have in the neighborhood of 5 mg of caffeine compared to 180 mg for its caffeinated cousin. These are some ballpark numbers because caffeine content is variable and dependent on plant species, grind, and other factors.

Ethyl acetate decaffeination is classified as a “solvent-based” method and these days the solvents used are limited to methylene chloride or ethyl acetate, both of which are completely safe. The potential for risk to human health is, according to the FDA, so low “as to be essentially non-existent.” In practice, residual methylene chloride amounts to one-tenth of that which is allowed by the FDA and even these acceptable traces don’t survive the roasting process, let alone brewing. Ethyl acetate decaffeination (aka “EA”) is even less of a concern. EA is sometimes labeled as “natural” because it is naturally present in ripening fruits, like apples.

Ethyl acetate can be used in a direct method or an indirect method. The difference between these two methods is virtually irrelevant to the coffee roaster. In both cases, what soluble material can be removed from the green coffee beans are extracted into water, the caffeine is removed by bonding with the ethyl acetate and then the “not caffeine” soluble materials, i.e. oils and flavor opponents, are reintroduced to the green coffee bean after 10-12 hours.

Ethyl acetate decaffeination is not the only method for removing caffeine from coffee. At Olam, we also use Swiss Water Process (SWP or SWD), which pushes caffeine removal to nearly 100% (99.9) and can retain more flavor components. Green coffee beans are cleaned and hydrated and the caffeine extracted. The caffeinated water is run through carbon filters until the caffeine is trapped and removed from the water, which is then reintroduced to the green bean.

Following World War II, decaffeinated coffee was most often available as an instant coffee product. By the 1970’s, decaf coffee in restaurants was associated almost exclusively with an orange packet of Sanka delivered to your table along with a cup of hot water. In fact, when restaurants started brewing decaf in the late ’70s rather than offering decaf only as instant coffee, they had to brew decaf into carafes with orange handles because that was the color the public had come to associate with decaf.  

Explore Our Decaf Coffees

It has been said that those who drink decaffeinated coffee are true coffee connoisseurs because they are more interested in taste than the side effects associated with caffeine. With that in mind, we at Clear Lake Coffee Roasters remain focused on taste when it comes to decaf coffee, whether it be Swiss Water Process or ethyl acetate decaffeination. How does it taste? If you find it on our website, that means it tastes pretty darn good.