A vacuum coffee maker brews coffee using two chambers where vapor pressure and gravity produce coffee. Design and composition of the vacuum coffee maker varies. The chamber material is borosilicate glass, metal, or plastic, and the filter can be either a glass rod or a screen made of metal, cloth, paper, or nylon.
source/image(PrtSc): Jonathan Katz-Moses
In this woodworking science build video we make a Vacuum Coffee Maker out of chemistry equipment. It has epoxy pours and lichtenberg figures. Watch the video from Jonathan Katz-Moses for more info:
It uses the simple science theory of what goes up must come down. The water boils and forces air out the top. When heat is removed, the water is forced through the filter and back down into the flask.
After your coffee grounds have soaked for a while, becoming more loose and relaxed, the vacuum created in the bottom chamber pulls all that caffeine-saturated liquid back down through the filter. By forcing the water back down through the grounds, this method is also effective in extracting any remaining solubles your coffee grounds still cling to.