The reason I use Coffee Syphons (also known as Conas and Vaculators) to brew in is that they are simply the best! No other brewer that I have seen can give the same purity of flavor and lack of bitterness. I believe that this is due to the exquisite temperature control, since the coffee brews at about 2ºC below boiling point, without ever actually boiling. However it happens, I recommend them, and use them at home. I sell a home model made by BODUM for $A99.00, as I regard this as the best value syphon in the world. The equivalent Cona model, while a beautiful unit, costs 4 times as much! The Bodum Santos can brew a minimum of two cups and a maximum of eight. It works well on either gas or electric hotplates (I use gas at home) as long as it can sit level. If the hotplate doesn't allow this then you need a wire mat, since when all the coffee is up the top the unit is top heavy and can fall over (major catastrophe!)

The 2 main components are a funnel and a bowl. The filter (and these are of various types) sits in the funnel and acts as a valve.

It will allow water (or Brewed Coffee) to move freely but traps the grounds in the funnel.

I fill the bowl with (usually) boiling water and measure medium grind coffee into the funnel, after placing the funnel into the bowl. I normally use 10g, one rounded dessertspoon, of ground coffee per cup. The funnel is then seated into the bowl, with a twist to seal the rubber gasket.

I then place the assembled syphon on to a hotplate - gas or electric is O.K., and I have used both - and this is where the interesting bit starts to happen. The build up of steam in the lower bowl forces the water up into the funnel, where it mixes with the ground coffee. A quick stir wets the grounds into the water, and a small amount of water left behind in the bowl keeps the steam coming and the temperature constant. Brewing continues for 2 minutes for a full batch, or less time for less coffee ( it can go longer but you don't get any more flavor). I then take the syphon off the hotplate.

I put it on a cork mat, which allows the bowl to start cooling. With no more steam being produced, a vacuum forms in the bowl, which sucks the brewed coffee down through the filter.

Finally the funnel is removed and placed in a stand, (I use a straight sided 400ml acrylic tumbler, just the right size and very cheap) and the bowl, filled with delicious, hot, coffee, is ready to pour