The Siphon Coffee Maker, also referred to as a vacuum coffee maker, requires more of a hands-on effort than most other methods of preparing coffee. With slight variations in water temperature, timing, and the amount of coffee grounds use you are able to greater control the coffee’s outcome. It is exciting to watch the brewing water as it ‘defies gravity’ but may be a bit more work than the average joe requires first thing in the morning. If you’re interested in learning more about the Siphon Coffee Maker, read details of how it works below and brew-on coffee makers!
Siphon coffee makers are made up of four parts: the bottom container where the water initially sits and the brewed coffee eventually rests; a top container that has a siphon tube attached to it (and a hole in the bottom of the vessel), where the coffee brewing takes place; a type of sealing material (usually a rubber gasket) to help create a partial vacuum in the lower vessel while brewing is taking place, and a filter, which can be made of glass, paper, metal, or cloth.
There is also a heating source, and there’s usually three types – a cloth-wick alcohol burner (slowest), gas or electric stovetop (faster), or a specialty butane burner (fastest). There are additional heating devices, including the halogen burner system that is part of the $20,000 setup that Blue Bottle Cafe in San Francisco has for their siphon coffee makers.
Once the siphon coffee maker is assembled, heat is applied to the lower container. As it heats up, some of the water is converted to a gas – water vapour. A gas occupies a lot more space than its liquid or solid variant, and it can expand as more heat is applied. Gas can be compressed, but only to a point, whereas liquids do not compress. The water vapour continues to expand and it seeks some relief from all the compression it’s starting to have. The only escape route out of the bottom vessel is the siphon tube traveling up to the top, but the problem is, there’s a lot of liquid blocking its way. So what does the gas vapour do? It pushes the water up the siphon tube!
SRC: Find out how the brewing water makes it’s way up the Siphon and the history of the Siphon Coffee Maker at: coffeegeek.com/guides/siphoncoffee