What are the effects of using ultrasound to extract espresso?
A research team led by Francisco Trujillo, a senior lecturer at the University of New South Wales, has developed a method for extracting espresso using high-frequency ultrasound. The technology has shown the potential to reduce energy consumption by approximately 75% compared to conventional espresso machines at the same beverage concentration.
Ultrasound enables espresso-strength coffee brewing in 2–3 minutes at low temperature with lower energy consumption - ScienceDirect
I used sound waves to make espresso. It could cut coffee-brewing energy use by 75%
https://theconversation.com/i-used-sound-waves-to-make-espresso-it-could-cut-coffee-brewing-energy-use-by-75-284929
Trujillo conducts research on coffee and espresso extraction, and in 2024 he announced a technology that uses ultrasound to reduce the extraction time for cold brew coffee to just 3 minutes.
A technology using 'ultrasound' has emerged that shortens the extraction time for cold brew coffee from 24 hours to 3 minutes - GIGAZINE
This time, Trujillo and his research team attempted to shorten the espresso extraction time by using water at 20°C to 30°C, rather than cold water like that used for cold brew coffee. Espresso is characterized by its significantly stronger flavor than regular coffee, achieved by adding boiling water under pressure to finely ground coffee.
First, the research team developed the following device: They attached an 'Ultrasonic Horn' to the side of the coffee basket in an espresso machine, which transmits ultrasonic waves. The ultrasonic waves break down tiny bubbles created in the water, promoting the extraction of flavor components and caffeine from the surface of the coffee grounds.
The following diagram shows the vibrational displacement of the coffee basket wall, based on the simulation results. The entire basket vibrates, not just at the single point where the horn at the bottom makes contact, resulting in a structure where ultrasonic energy is transmitted to the coffee grounds from multiple locations.
In the experiment, water at approximately 22°C was used, and finely ground coffee powder was exposed to 100W ultrasound for 3 minutes. As a result, the total dissolved solids reached a maximum of 9.86%, which falls within the range of 8-12% considered typical for espresso. The extraction rate also did not increase sufficiently under conditions without ultrasound, but reached 18.03% under the fine grinding condition with ultrasound. This value reaches the range of 18-22%, which is considered a good indicator of balanced extraction.
This image shows the aluminum foil used as a base for the basket in the experiment. The area enclosed by the red dotted line labeled H represents localized damage observed on the aluminum foil after being exposed to 100W ultrasound for 3 minutes. The research team states, 'The rough and thinned surface near the edge of the basket indicates that the bubbles that formed inside the basket collapsed rapidly.'
Espresso extracted using ultrasound showed no significant differences in caffeine concentration, chlorogenic acid concentration, pH, or color compared to conventionally extracted espresso. Furthermore, no statistically significant differences were observed in the overall composition of aroma components, demonstrating that consistent quality can be maintained even with low-temperature extraction.
The sensory evaluation of taste involved 100 people who drink coffee at least once a week. When ultrasonically extracted espresso and regular espresso were served at room temperature, there was no significant difference in evaluation between the two products in terms of aroma, flavor, bitterness, and overall likability. In the measurement of energy consumption, it was found that when the beverage concentration was the same, the power consumption of the ultrasonic extraction system was only 24.3% of that of a conventional espresso machine, which is about 75% less.
Furthermore, in the case of filter coffee, ultrasonically extracted coffee was preferred over conventionally hand-drip coffee. The research team argues that using an ultrasonic extraction method makes it possible to use concentrated, low-temperature coffee as an ingredient in bottled beverages, milk-based beverages, and cold coffee, and also leads to energy savings in the manufacturing process.
Related Posts:
