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Where does the Caffeine Go?

As Green As It Gets’ Primer on Decaffeinated Coffee...

caffeineCaffeine is removed from green coffee beans by soaking them in a solvent that is capable of dissolving caffeine. In the old days, these solvents were light hydrocarbons, like the butane in your cigarette lighter or the benzene that is added to your gasoline. The idea of coffee soaked in carcinogens wasn’t palatable, so new solvents came into vogue.

Today, most decaffeinated coffee is soaked in ethyl acetate (nail polish remover) or methylene chloride (paint stripper) to remove the caffeine.

Some folks thought that the step from lighter fluid to nail polish remover as a healthier means of decaffeinating coffee wasn’t much of a step. A new process came about, soaking coffee in pressurized liquid carbon dioxide to remove the caffeine. It is a more palatable alternative, but has not become widely marketed.

Aside from the obvious downsides of soaking your food in industrial chemicals, these processes have a second problem. They take out not only the caffeine from the coffee, but also all elements of the coffee that tastes good. Your coffee pot is basically a low-tech device that takes the essential oils out of the coffee bean and dissolves them in hot water. The high-tech decaffeinator takes out those same oils, and leaves the beans weak when they are brewed.

As Green As It Gets' decaffeinator doesn’t use any scary solvents that you find in oven cleaners. It doesn’t use any chemicals you find next to the heavy-duty rubber gloves at your hardware store. We sequester carbon dioxide, so we don’t want to produce it to make our decaf coffee. And, we wanted coffee to taste good. We needed a new process.

It turns out there is one liquid that is very safe, non-volatile, non-flammable, healthy, and just generally good at taking caffeine out of coffee but leaving all the good tasting essential oils in the bean. You’ve seen it before. You’re quite familiar with it.

You know it. It’s ridiculously simple. Give up?

That miracle solvent is none other than decaffeinated coffee. That’s really only a little more than water. We know water can dissolve caffeine—that’s how it makes it into your coffee cup. But it takes out all the oils that make your coffee taste like coffee. Decaffeinated coffee, the beverage, has no caffeine, so it wants to soak up caffeine. Meanwhile, it’s already full of the good-tasting coffee oils, so it doesn’t want to dissolve any more. Decaffeinated coffee is a natural solvent that has a natural affinity to dissolve caffeine without taking the flavor out of the bean.

This process of course has a downside. Once the liquid coffee touches the beans, it absorbs the caffeine, and is no longer decaffeinated. The challenge is no longer how to get the caffeine out of the coffee bean, but rather out of the liquid coffee so that it can continue to function.

At As Green As It Gets, we make a filter media that can remove caffeine from the circulating fluid. That filter is made from activated carbon, much like the material in your kitchen faucet filter or a backpacker’s water filter. The only difference is our activated carbon is made to be predisposed to filtering caffeine.

Keeping with our principles to vertically integrate businesses, we have set up a small business making activated charcoal. We grow our own raw material in the form of seeds, nuts, and even grass. This is heated without oxygen until it reaches its combustion temperature. Unable to burn due to lack of oxygen, the vegetable matter volatilizes, gives off gas. That gas is captured and burned to further heat the vegetable matter, which gives off more gas, which burns hotter, and a run-away reaction takes place. The result is a sort of porous lattice of pure carbon with cavities sized to chemically accept molecules like those that were driven off by the heat.

Those pores are sized closer to natural gas, and we want them to accept caffeine. So, we enlarge those pores by exposing them to high pressure oxidizing steam and a few other miracles of science. Now we have a filter sized specifically to caffeine.

Now we make our decaffeinated coffee. It is made with warm water and green, unroasted coffee beans. That water absorbs the oils in the coffee, and the resulting liquid is called “Charged Water.” The beans are removed from the system, and the beans to be decaffeinated are added. The charged water then cycles through the system, first to the heater where it is warmed, over the beans where caffeine is dissolved, through the filter media where the caffeine is removed, through an ultra violet purifier to keep the water sterile, then the cycle begins again.

We measure the caffeine content of the coffee beans using a steam and alcohol extraction. When the coffee is 99.9% caffeine free, we stop the decaffeination. The charged water is distilled, creating a highly concentrated liquid and distilled water. The coffee beans are soaked in the concentrated liquid, giving the beans a chance to reabsorb any flavor elements that may have been lost. Then the coffee beans are washed in distilled water, dried in the sun, and are ready to roast.

The entire process is very green. The only energy inputs are the electricity to run the pump and fuel to run the heater. The heater is two-stage, first preheated by the sun, then brought to higher temperature through green biofuels made on site. There are no hazardous chemicals. An accident at our facility would be no more damaging to the environment than a spilled cup of coffee.