Written by JulieReading time 9 min
Today, I’m going to tell you all about decaf coffee. However, it’s impossible to explain the phenomenon of decaf without using words that feel like they’ve come straight out of your school chemistry textbooks! So if I’ve piqued your curiosity, then make yourself comfortable, reach for your periodic table and, above all, pour yourself a good cup of coffee – with or without caffeine. We’re about to explore the mysterious world of decaffeination.
What is Caffeine?
First things first: what is caffeine? Naturally occurring in coffee cherries, caffeine is a brain stimulant that makes us more alert. It was isolated for the first time in 1819, from a coffee bean. For all you budding chemists, here is a visual illustration of a caffeine molecule. The amount of caffeine found in coffee varies depending on the species and variety of the coffee plant:
- Coffea Arabica contains around 1% caffeine
- Coffea Canephora, including the Robusta variety, contains between 2% and 5% caffeine
These amounts will obviously vary depending on the conditions (such as terroir or specific location, altitude and shade) in which the coffee has been grown. For example, the higher the altitude, the lower the caffeine content. This is because caffeine is a natural insecticide that tends to develop more at lower altitudes in order to protect coffee plants from pests.
How is Coffee Decaffeinated?
Decaffeination is only ever carried out on green coffee (beans that have already been subject to the initial processing phase). In other words, it is always performed prior to roasting. In the vast majority of cases, the decaffeination itself is carried out at a specialist facility. Regardless of the chosen method and/or products used, coffee that is being decaffeinated will always undergo several procedures:
The coffee beans are soaked so that they become permeable.
They are then mixed with a solvent* to allow the caffeine to filter out of them.
The grains are washed to remove any remaining trace of the solvent.
Lastly, they are dried so that they can be shipped for roasting.
Following decaffeination, the coffee should have a caffeine content of 0.1% or less. Depending on the type of decaf coffee you want to make, there are several decaffeination methods to choose from. So let’s find out all about them!
* defined as having the capacity to dissolve, dilute or extract other substances without chemically changing them. For example, water is a solvent.
Decaf Coffee with Organic Solvents
1/ Ethyl Acetate Decaffeination
Ethyl acetate is made from a mixture of fermented sugar cane and vinegar. It is naturally found in grapes or rum (to be consumed in moderation). Ethyl acetate decaffeination is a very simple process. The coffee beans are soaked in various baths containing water and the solvent, until the caffeine content is reduced to 0.1% or less. After a thorough rinsing, the coffee beans are ready to be roasted.
2/ Methylene Chloride Decaffeination
- Direct Method: The method is the same as with ethyl acetate, but the beans are given a much more thorough rinsing at the end in order to extract any last traces of methylene chloride. For health reasons, the presence of this solvent in coffee is strictly regulated at the European level.
- Indirect Method: Unlike the direct method, the aim here is to prevent the coffee beans from coming into contact with the solvent. The beans are therefore left to infuse in water in order to dissolve both the aromatic molecules and the caffeine. The beans are then removed from the water bath and the solvent is added. The water is heated so that the caffeine and solvent evaporate. Lastly, the beans are returned to the water to re-absorb the aromatic molecules that they lost.
In most cases, if the decaffeination method is not specifically indicated on the packaging, methylene chloride will have been used.
Decaf Coffee with Natural Decaffeination
1/ Water Decaffeination
Not even organic solvents are used here! The beans are simply infused in successive water baths until a minimum caffeine content of 0.1% is reached. Generally, caffeine is actually added in the first baths in order to accelerate the decaffeination process. Believe it or not, the caffeine attracts the caffeine!
2/ Swiss Water Decaffeination Process
The idea of this method is to produce more flavoursome decaf coffee beans than with standard water decaffeination. The procedure is therefore a little more complex:
A first batch of coffee, which is not intended for consumption, is soaked in water in order to separate the aromatic molecules and caffeine from the beans.
The caffeine is captured via an activated carbon filter. This leaves the water in the bath saturated with aromatic molecules.
A new batch of coffee (to be decaffeinated) is immersed in the flavour-saturated water. This time, only the caffeine will dissolve.
The freshly decaf coffee beans are removed, washed and dried.
CO2 Decaffeination: a Modern Method
This method is by far the most expensive, as it requires a significant amount of specialist equipment. Indeed, carbon dioxide decaffeination can only be carried out in a tank that can withstand a pressure of 200 bars. Allow us to explain! The grains are placed in a CO2 tank under a pressure that is 200 times greater than the earth’s atmosphere. Under such pressure, the CO2 is transformed into a state between gas and liquid, known as “supercritical”. The beans are passed through the supercritical carbon dioxide, which extracts the caffeine from them. The decaf coffee beans are then washed and dried. Whichever method has been used to decaffeinate the coffee, the caffeine is stored and resold to pharmaceutical and cosmetic laboratories or to the food industry.
Decaffeination: Does it Affect the Taste of my Decaf Coffee?
We may as well be up-front about this: decaffeination will always have an impact on the quality of the coffee and the taste of your drink! These processes change the structure of the coffee beans and, as a result, we’re left with a less expressive coffee that may well have developed what is known as a “decaf coffee taste” or “decaf coffee marker”. Many people associate the latter with the taste of liquorice. The way that the flavour is affected will depend on the decaffeination method used:
- Ethyl acetate decaffeination: This method favours the development of fruity notes. This decaf coffee will taste sweeter and more aromatic than other decaffeinated coffees, with a less pronounced decaffeinated flavour.
- Methylene chloride decaffeination: In addition to removing the caffeine and reducing the aromatic characteristics, this method can also leave an aftertaste of solvent.
- Water decaffeination: This is one of the methods that alters the aromatic profile of the coffee most strongly. The result is a decaf coffee with little expression and a strong decaf taste.
- Swiss water process decaffeination: Although the taste of the coffee will be better preserved than with water decaffeination, there will still be a degradation of the coffee’s aromatic profile. The decaf coffee marker will be very weak.
- CO2 decaffeination: This method is used on low-quality coffees and has the least impact on the flavour of your drink. However, once extracted, the decaf coffee will be relatively light-bodied. CO2 decaffeination is increasingly being used on decaf specialty coffees, as it is suitable for smaller volumes.
8 Things You Need to Know about Caffeine
When you dig a little deeper into the world of decaf coffee, it quickly becomes clear that there are questions hiding around every corner! There is a LOT of information out there regarding decaf coffee so it’s very easy to feel lost. Don’t hesitate to do your own research and read the many articles written on the subject. That’s why we’ve put together a little selection of things you should bear in mind if you’re trying to limit your caffeine consumption:
Filter coffee has a higher caffeine content than espresso. The more contact the grind has with the water, the more caffeine develops. If you’re sensitive to caffeine, avoid non-decaffeinated filter coffee from late-afternoon onwards!
Caffeine is partly responsible for the bitter taste that develops during roasting. This is why Robusta-based coffee tends to be more bitter than 100% Arabica coffee.
Caffeine and pregnancy: during pregnancy, it is advisable to reduce or even stop caffeine consumption, for your own health and that of your baby. However, we’re all different and not everyone absorbs caffeine in the same way. We recommend that you ask your doctor for advice.
The big question: can you drink coffee at night? If you’re talking about decaffeinated coffee, the answer is yes! As we’ve already seen, decaf contains about 0.1% caffeine. So you can enjoy a little after-dinner treat without worrying about the effects of the caffeine, which would otherwise kick in around 30 minutes later!
Is caffeine an effective way of preventing migraines? Caffeine is a vasodilator and can naturally relieve certain ailments! It is also added to certain pharmaceutical products – those with a base of ibuprofen, for example – in order to accelerate the effects of the medicine.
Caffeine and theine are actually the same substance. However, their effects on our body are not the same. The effects of theine are generally milder, but they last longer (approximately 4 hours for caffeine, 8 hours for theine).
According to a study by the ALZHEIMER Foundation, caffeine and theine act on a receptor that causes Alzheimer’s disease and could therefore limit the risk of the disease.
Originally, coffee was consumed purely as a stimulant and was therefore considered more of a medicine than something to be drunk for pleasure. But when the first coffee houses opened, the coffee break became an occasion in itself and the social side of it started to outweigh the pharmaceutical benefits!
If you’ve got this far, you should now have all the information you need to choose the decaf coffee that suits you best. However, as we’ve seen, the decaffeination process does have an impact on the aromatic profile of your drink. So if you’re looking for a coffee that truly expresses the character of its terroir, and you have no problem with caffeine, then you’re still better off sticking to a good old cup of classic coffee.
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