In the large family of caffeinated drinks, Cold Brew is a method of preparation that requires a lot of time, 12 hours at least. Osma promises to reduce this time to just a few minutes using acoustic cavitation.
Cold Brew is a method of preparing cold coffee that is gaining more and more followers. The idea is not to cool a normal coffee obtained with hot water, but to make a drink as one would prepare an iced tea. We therefore leave the grind to infuse in cold water so that it exhales different flavors from those that can be found in a hot coffee. As original as this method is, it requires a little planning, because the process takes time. It takes between 12 and 24 hours to obtain an interesting drink, which can then be diluted with water, adding an ice cube to obtain an even more refreshing drink.
It is to overcome this drawback that the Osma Pro machine was born. Reminiscent of a classic espresso machine, with a clip-on filter holder under the dispensing orifice, the Osma Pro however operates in a closed circuit. The container that acts as a water reservoir also serves to receive the drink obtained, thanks to the pipe that is immersed in it. The water is drawn in and then passes through the grind and an acoustic cavitation system creates the pressure needed to extract the flavors from the powder, without the need to heat the water.
Acoustic cavitation? Kesako? We contacted Benjamin Aulier, chemical engineer at SinapTec, a “Independent SME that has acquired more than 35 years of expertise in the development and implementation of ultrasound technology“.
“When you use ultrasound in a liquid medium, under certain amplitude conditions, you will create cavitation. Cavitation is nothing more than the vaporization of a small amount of liquid“, he explains to us. “This phenomenon will form a sphere, roughly a vacuum bubble, which will want to return to its state of equilibrium. When it does, it will implode on itself, generating local increases in pressure and temperature. And if you have coffee particles“, he continues, “even small ones (ground coffee for example), you will modify the surface state of this particle and extract caffeine, but not only since you will also release the aromas“. And to add: “I had done a few tests with a barista a while ago, and it works very well“.
Even if the liquid heats up a bit, Benjamin points out that it is possible to contain this rise in temperature: “According to the frequency and the vibratory amplitude, the increase in temperature can be diverse and varied. Some of our equipment allows you to gain 1°C every 30 seconds or 1°C every 5, 10 minutes“.
No need to have a Master’s degree in particle physics to use the Osma Pro: a simple press of the one and only button on the right side of the device is enough to start the preparation. While it is quite normal that no temperature adjustment is provided (we are talking about a cold drink after all), it will be necessary to play with the amount of water and the number of passes through the filter to modify the intensity of the drink.
For now, the Osma Pro, proudly produced in Oregon, is only available on the manufacturer’s site for $695. However, it seems possible to have it delivered to France.