A siphon bar or vacuum coffee maker uses vapor pressure & vacuum force to brew coffee. Many believes this would give coffee a cleaner, crisp, rich & smooth taste.
As a coffee aficionado myself, I believe the attraction to siphoned coffee is purely based on placebo effect.
To prove my point, I have built my own vacuum coffee maker for using only a moka pot & a glass salt shaker. Of course, you can also purchase a Bodum Santos for less than $100, but where is the fun in that?
My total cost was much lower than $20,000. Granted, I did not have fancy glass globe as the water reservoir.
After filling moka pot's boiler with water, I placed empty salt shaker over the top & coffee ground around it.
Heat.
Similar to regular siphon coffee maker, water has expanded after heating & traveled upward into the upper chamber.
After removing the moka pot away from heat source, brewed coffee siphons back into lower chamber as it cools.
Voila! Now you can also enjoy the same kaleidoscopic beverage all the pretentious hipsters are raging about.