How is Decaf Coffee Made? How to Brew Decaf Coffee?

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Factors Affecting Caffeine Content

Factors that influence caffeine content levels include coffee bean variety, steeping time, grind coarseness, brewing method, water temperature, extraction time, and more. Caffeine has some effects on the body, which has led to the popularity of decaffeinated coffee.

What is Decaffeinated Coffee?

Decaffeinated coffee refers to coffee that undergoes special processing before roasting to remove 96%-98% of caffeine. A cup of such coffee contains approximately 5% of the original caffeine content. Generally, there are three methods for caffeine removal:

1. Solvent Extraction Method

Direct Extraction Method:

Coffee beans first undergo softening treatment, then are heated with high-temperature, high-pressure steam to expand the bean surface and increase contact area. After this, dichloromethane (CH3CI) solvent is added, allowing the beans to come into contact with the solvent to extract caffeine.

This method uses dichloromethane to adsorb and dissolve caffeine from the bean surface, but it's less likely to affect the coffee's flavor.

Indirect Extraction Method:

Beans first undergo softening treatment, then are placed in warm water. The caffeine and other components from the beans dissolve into the warm water, creating a coffee essence solution. This solution is then transferred to another container where dichloromethane is added. When heated, caffeine evaporates with the extraction solution. Finally, the caffeine-free essence solution is returned to the coffee beans in warm water, allowing the beans to reabsorb the lost components.

This method uses indirect extraction but is more likely to lose coffee flavor.

2. Swiss Water Process (SWP)

Coffee beans are first soaked in warm water. After caffeine and other components dissolve into the water, activated carbon filters the caffeine from the essence solution. Then, the caffeine-free essence solution is returned to the original coffee beans, allowing them to reabsorb the lost components.

This method emphasizes not using any chemical solvents for caffeine extraction, making it a choice for health-conscious consumers. Although no chemical solvents are used, some coffee components are also filtered by the activated carbon, resulting in some loss of coffee flavor. Additionally, decaffeinated coffee produced by this method is relatively more expensive.

3. Supercritical Carbon Dioxide Extraction Method (SCF)

Large amounts of carbon dioxide (CO2) are generated during coffee bean roasting. When this carbon dioxide is processed under high pressure to become liquid, it can be added to treated coffee beans to remove caffeine. The pressure is then released, causing the carbon dioxide to convert to gas and evaporate.

This method removes caffeine without damaging the coffee beans, doesn't change their color, and is less likely to extract substances other than caffeine, preserving the original flavor of the coffee beans. However, because it requires special high-pressure environments and significant equipment investment, decaffeinated coffee extracted using this method is less commonly found on the market.

FrontStreet Coffee's Pour-over Brewing Recommendations:

Little Fuji 3.5 V60 dripper, 90°C water temperature, 1:15 ratio, total duration of two minutes.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473