The vacuum coffee maker was invented in the 1830s in Berlin. Although not widely used today, it is known for producing coffee that is crisp, rich and smoother than that produced by other methods. It is also known as a vac pot or siphon coffee maker. The design can vary but generally uses two chambers of pyrex, metal or plastic, with a glass rod filter or a screen of metal, cloth, paper or nylon.
How It Works
In a vacuum coffee maker, water is heated in the lower vessel of the device until expansion forces it through a tube into an upper vessel, which contains coffee grounds. Once the lower chamber is relatively emptied and enough time has elapsed, the heat is removed and the resulting vacuum draws the brewed coffee through a strainer back to the lower vessel, from which it can be served. The coffee maker must be taken apart in order to pour the coffee.
A balance siphon is a variation of the vacuum brewing principle. In it, two chambers are arranged side by side with a counterweight attached to the heated chamber. Once vapor forces hot water out, the counterweight activates a spring-loaded snuffer that smothers the flame. As the initial chamber cools down, a vacuum is created and the brewed coffee seeps in.