MAIN PROCESSES
Surely you have ever wondered how caffeine is extracted from coffee? Well, several methods have been modified and perfected over the years. The main ones are Decaffeination by chemical solvents, decaffeination by water, and decaffeination with supercritical fluids: CO2.
In most decaffeination processes, the caffeine is extracted from the green coffee before it is roasted and ground. Nowadays, the processes have evolved considerably, reaching 99% caffeine extraction. To obtain a good decaffeinated coffee, we must start with a good bean of equal quality.
Good decaffeinated coffee starts from a quality bean. A low-quality coffee continues to be just as bad with or without caffeine.
DECAFFEINATION BY CHEMICAL SOLVENTS
Let's think about the home method for making bleach-washed jeans (the horror of the 80s) and we'll get an idea of what this process is like. We put the jeans in water with a good splash of bleach and wait long enough until they start to fade and we see blue water.
Well, replace bleach with methylene chloride or ethyl acetate which are suitable for food, your favorite jeans with green coffee (which swells with the water and facilitates the extraction), and the blue of the denim which would be the extracted caffeine. Repeat the process several times and we have it. As in the pants, traces of solvents may remain adhered. They are eliminated by using steam and subsequent drying to recover the initial moisture levels.
Advantages: good performance in extractions.
Disadvantages: a certain unpleasantness when minimal traces of solvent remain in the coffee, although experts and health authorities certify that there is no impact on health. It is also necessary to have very well-controlled technical facilities to avoid accidents.
Fifty percent of world production is carried out by this method.
WATER DECAFFEINATION
Although all the processes use water in some of their steps, Mountain Water and Swiss Water Process are the two methods that are cataloged as decaffeinated "by water". In both cases the water hydrates the green coffee bean, expanding the cellular structure, which facilitates the extraction of the caffeine. The caffeine - which is soluble in water - is extracted into the water and captured through a filter. Swiss Water uses a patented active carbon filter that specifically traps caffeine. Mountain Water, the name given to the process by Cafetalera Sanroke of Mexico, also uses a filter to capture the caffeine.
Advantages: It is a natural process free of chemical elements. It has no handling risks and no environmental impact.
Disadvantages: it is more costly and the extraction yields are lower.
22% of world production is carried out by this method.
DECAFFEINATION WITH SUPERCRITICAL FLUIDS
Competing in the cool name category with Swiss Water, we have this process with supercritical fluids. CO2 is the most common supercritical solvent, although there are others. At a given temperature and pressure it behaves partly as a liquid (solvating power), partly as a gas (diffusing power). The process is as follows:
Coffee beans are soaked in pure water. In this way, the pores are opened and the caffeine molecules begin to move. Carbon dioxide (100% natural) is then added to the water at 100 atmospheres of pressure, creating sparkling water. The carbon dioxide acts like a magnet and attracts the caffeine molecules. When the caffeine is captured, the carbon dioxide is removed from the water. This element is very selective and does not affect the carbohydrates and proteins in the bean. After the extraction process, the seeds are dried naturally. The carbon dioxide is then recycled and the caffeine is sold for commercial uses.
Advantages: It extracts caffeine with great efficiency. It does not use chemicals in the process even though it is a direct contact method. It does not affect the proteins and carbohydrates of the bean. It is a natural method and 100% recyclable.
Disadvantages: cost of the process due to the initial investment in machinery and subsequent maintenance.
20% of world production is carried out by this method.