Today, the global demand for decaffeinated coffee products is steadily increasing. This is a high–value product because it meets the needs of a growing group of consumers seeking coffee without caffeine.
In Vietnam, however, this product line has not yet received much attention from coffee processing companies. To prepare for this emerging market, researchers in the country have already explored a method for removing caffeine from roasted coffee beans.
A research team from Ho Chi Minh City University of Technology conducted experiments to find a fast and efficient way to decaffeinate roasted coffee. They tested various assisted–extraction techniques—ultrasound, microwave, and heat—using an ethanol/water solvent system on medium–roast robusta coffee beans. Their results showed that performing three microwave–assisted extraction cycles, each lasting four minutes, could remove 49.26% of the caffeine, with only 4.98% loss of total dry matter.
This method caused no significant changes in the physical and chemical properties of the beans and had minimal effect on their outward appearance. A sensory evaluation comparing ground coffee from regular beans and decaffeinated beans found that the aroma and bitterness were slightly improved.
Previous studies have shown that caffeine can be extracted using methylene chloride, methyl acetate, ethyl methyl ketone, trichloroethane, supercritical CO₂, or water. Most of these methods are traditionally applied to green coffee beans. More recently, some studies have investigated removing caffeine from roasted coffee or from coffee extract, as well as restoring co-extracted flavor components. However, these methods are generally used in the production of instant coffee.
The Vietnamese study demonstrated that using 60% ethanol solvent at a 7:1 solvent-to-coffee ratio, combined with microwave-assisted extraction, can effectively decaffeinate medium-roast robusta beans. This technique removes caffeine while preserving the beans’ appearance and the sensory qualities of the brewed coffee.