What is decaf?
We often say around Deeper Roots that decaf drinkers are the truest form of coffee lovers: they’re not in it for the caffeine, they’re just in it for the love of the game. We take our decaf pretty seriously, but how does a plant that naturally produces caffeine become decaffeinated? There are three main methods you’ll see us roasting – let’s look at them.
but first, caffeine.
Before we do that though, let’s talk about caffeine itself. What is caffeine? Caffeine is a convergent evolution in around 60 plants; this means that it evolved pretty much independently in plants as diverse as coffee, tea, cocoa, and even some flowers. Caffeine originally evolved as a pest deterrent. If you, as a plant, simply kill the pests that attack you evolution will self-select for those individuals that are resistant. Instead, caffeine evolved to confuse and in the case of some flowers, attract insects. In what amounts to a happy accident of evolution, this molecule blocks receptors in our brain for adenosine, a chemical that produces sleepiness – hence that jolt of energy we’re all familiar with.
now, the processes.
To decaffeinate coffee, raw, normally caffeinated coffee beans are put through one of several processes, we’ll focus on three: ethyl acetate (sometimes called sugar cane processing), mountain water processing and Swiss Water processing. Though these three processes differ, they start out the same way. Raw coffee beans are brought to a decaffeination facility and washed to remove dust or any foreign objects. Next, they are polished to remove the silver skin layer and steamed. The act of steaming coffee beans helps to open them up on a cellular level, so that they are more receptive to having caffeine removed.
Here is where the processes differ: you next add a “solvent” to the raw coffee to remove the caffeine. A solvent is a substance that dissolves a “solute,” or a specific compound we’re trying to get at (in this case, caffeine and hopefully nothing else). In sugar cane processing the solvent is ethyl acetate – which might sound like a scary artificial chemical but is a naturally occurring chemical called an ester made up of alcohol and acetic acid (vinegar). It’s found in apples and pears and is a byproduct of fermenting sugar cane into molasses. The raw coffee is added to a sealed tank along with the ethyl acetate, and it’s held at a specific temperature and refreshed with new ethyl acetate as many as 10 times over about 8 hours. It’s agitated constantly to help “wash” out the caffeine. We use ethyl acetate because it’s very selective: it takes out caffeine but leaves most of the other compounds that make coffee delicious. Afterwards the tanks are flushed with steam for about two and half hours, causing the ethyl acetate to boil away. Finally, the coffee is dried and cooled down before it’s packed and sent to us for roasting.
Mountain water processing is very similar to ethyl acetate, however the solvent used is a proprietary blend called green coffee extract. While we don’t know exactly what’s in this, it is made from coffee, contains most of its solubles, yet leaves a convenient gap where caffeine should be. When you add the green coffee extract to water and raw coffee and heat it up, only the caffeine will extract from the raw coffee, because everything else is balanced. Swiss Water is, again, very similar but is an intellectual property secret. After coffees processed these three ways are dried, they’re tested rigorously to make sure no solvent remains, as well as making sure the caffeine has been completely removed.
freshly picked coffee before “wet milling”
That’s a lot of science but suffice to say that to decaffeinate coffee you need a solvent, and that solvent is either ethyl acetate or green coffee extract, depending on the process. You won’t ever see us use something called methyl chloride, an erstwhile solvent used to decaffeinate. It’s been found to be harmful in even small quantities, so we stay away from it. Regardless of the process, we roast it to perfection and make sure that you can be sipping any time of day or night.