Syphon Brewing

August 31, 2016

Do you love coffee? Have you secretly dreamed of being a mad scientist? Well break out your lab coat and protective goggles, because the Syphon brewing method may be the perfect medium to explore your inner chemist and experience a whole new cup of coffee.

There are five main parts to a syphon brewer, here they are from top to bottom:

  1. A container for grounds
  2. A filter
  3. A gasket 
  4. A container for water (with a tube connecting the two containers)
  5. A burner.

This brewing method works by applying heat to the water in the bottom bulb shaped container, exciting the water molecules and converting some of them into vapor. The vapor molecules get excited and begin to expand. They want to rise but the water is blocking their way, so the vapor pushes the water up through the filter and into the grounds container. This is the really cool part to watch, because it seems as though the water is defying gravity.

By keeping the water heated but below boiling point, the vapor will continue to push the water upward into the top container and agitate the grounds until the vapor can make its way up the tube instead. You’ll notice the tube from the top container doesn’t reach all the way to the bottom of the lower container, once the water is below the length of the tube the vapor is finally able to rush up the tube. This action--plus the heat from the burner--forces the water in the upper container to stay where it is, while also heating the grounds container throughout the remainder of the brewing process. The grounds will look as though they’re boiling, but it’s simply the water vapor breaking free of its liquid captor.

Once the brewing is complete and the burner is removed, the gas starts to calm down and shrink and the gasket helps to create a partial vacuum to pull the brewed coffee down through the filter. The cooling water vapor begins to revert to its liquid form, quickening the flow back into the bottom container. Once all the liquid is back in it’s original container there’s still a vacuum to take take care of, so air is pulled through the grounds to balance back out the container to the normal atmospheric pressure in the room. This has an interesting drying effect on the grounds, which is the reason for the syphon’s nickname “vacuum pot”.