There are 4 different ways to decaffeinate the coffee beans used to make coffee that can be divided into solvent-based and non-solvent based methods.

With solvents, the general idea is that either ethyl acetate or methylene chloride is used to remove the caffeine from the coffee beans, either directly or indirectly. The other two methods are quite a bit more complex. They don’t use solvents, but rather some clever chemistry. Let’s take a look at each method in a little more detail.

Indirect Solvent Process

The Indirect Solvent Process is also known as the ‘European Method’ due to its popularity in Germany. First, the coffee beans are soaked in boiling hot water, extracting the caffeine and the flavor. The now decaffeinated and flavorless coffee beans are then removed from the water and either methylene chloride or ethyl acetate is added. This allows the solvent molecules to bond with the caffeine molecules. The water is then heated to a point where the bonded caffeine and solvent molecules evaporate, leaving all the flavors and oils in the water. Finally, to get all that flavor back into the beans, they are soaked in the water for many hours. This way the beans don’t touch the solvent, hence the name of the process. If coffee brands want to label coffee as ‘naturally decaffeinated’, they will use naturally occurring ethyl acetate, which is found naturally, instead of a synthetic version.

Direct Solvent Process

The Direct Solvent Process is the most simple process of removing caffeine from coffee beans. Basically, it just involves steaming the coffee beans to open their pores and then placing them in a solvent for about 10 hours. This simple task removes the caffeine directly from the coffee beans. Since it is so quick and efficient, it is the most common process used of removing caffeine from coffee beans today.

The Swiss Water Process

The Swiss Water Process is by far the most natural and organic way to decaffeinate coffee beans, but also the least cost-effective and most labor-intensive method. I’ll try my best to explain it but it gets a bit complicated. Hopefully, you will get a general idea of how it works.

This method relies on water and osmosis. The coffee beans are first soaked in hot water which causes the caffeine and flavors to separate from the coffee, much like the indirect solvent process discussed above. The coffee beans and water are then poured through a charcoal filter, which lets the flavor and oil compounds through, but filters out the caffeine. After this, there is a pile of flavorless, decaffeinated coffee beans. The beans are then discarded and a new batch of fresh coffee beans are added to the water and allowed to soak.

This happens over and over again until you reach a point where the water is so full of flavor that no more flavor molecules transfer from the coffee beans to the water. However, caffeine still does. This results in decaffeinated coffee beans with plenty of flavor. The decaffeinated coffee beans are then removed from the water, which can be used again to create another batch of decaffeinated coffee.

Supercritical Carbon-Dioxide Extraction Process

The Supercritical Carbon-Dioxide Extraction Process is the most recent development for decaffeinating coffee beans.

When carbon dioxide (CO2) is under 100 times the amount of pressure than it is at sea level, it begins to behave like a liquid. This state is called ‘supercritical’. First, the coffee beans are soaked in water, where the supercritical CO2 is forced through the beans at very high pressure. As this happens, the CO2 takes the caffeine out of the beans on the other side, leaving all of the yummy flavors within the beans. Once this is finished, the CO2 can be depressurized and used over and over again. Because of the cost to create this supercritical carbon dioxide, this process isn’t very common. I find this method to be the most amazing one. How somebody figured this out seems unbelievable to me.

INTERESTING FACTS

  1. Coffee is actually the pit of a bush’s berry which makes it a fruit.
  2. Coffee is the world’s 2nd largest traded commodity. Crude oil is first.
  3. Coffee stays warm about 20% longer if the cream is added to it.
  4. “Kopi Luwak” is the most expensive coffee in the world. It comes from Indonesia and is made from beans digested from the Asian Palm Civet (similar to a cat). It costs about $100 per cup. I personally would not drink this coffee due to many of these animals being captured and kept in harsh conditions to mass-produce this trendy coffee.
  5. Americans spend an average of $1,092 per year on coffee.

INTERESTING VIDEO

INTERESTING REFERENCES

  1. Agiboo.com – 16 most interesting facts to know about coffee
  2. BBC.com – How do you decaffeinate coffee?

Categorized in:

FoodScience