This cooling down results in a vacuum within seconds after you have snuffed the flame of the heat source.

Now please notice on the pictures, that the upper bowl has a hollow stem and a rubber seal to make an airtight connection to the lower bowl.

Once the heated water starts to produce steam, this pushes the water from the lower bowl upward through this stem into the upper bowl, that acts as a temporary reservoir, in which you  added your dry coffee grounds.

When no more water rises up, you may let it brew for a minute or so, then snuff the flame of the heat source and almost instantly the extract will be gentle sucked passed the filter back into the lower bowl.

This results in a perfect extract of all tasteful flavours of the coarse ground coffee beans. Only glass parts (of the ‘D-Genius’ model) come into contact with the brew.

As none of these components pick up any taste, next time you may brew any other extract in your Cona without any distasteful reminder of your previous brew. This makes it also perfect for the preparation of  tea, gluhwein or other extracts.


For professional quality assesment of coffee, there is no better gear with a higher degree of fidelity.

The modern-day Cona coffee brewer became an instant worldwide design-classic from the start of production in 1962 for good practical reasons, that still apply today.

Its elegant design and innovative use of quality materials came with a multitude of clever technical solutions. The taste has always remained marvelous.

The system brews your coffee at the exact right temperature (slightly hotter than your everyday electric pour-on brewer: a positive difference in taste, but on first encounter watch out not to ‘burn’ your tongue).

The Cona is a prime example of ‘form follows function’. The industrial design by Abram Games first creates steam to push liquid upward, followed by a reversal of the flow as steam cools down to ambient temperature in the lower bowl.

A. GEZANG & CO BV - Westvlietweg 65-P, 2495 AA Den Haag, The Netherlands


What makes the Cona so perfect for coffee devotees? Here is our answer!

Tel. +31-20-682 22 55       

The main characteristics of the CONA Size ‘D-Genius’ Coffee Maker:

• Patented “All-Glass” filter design of solid conical (“fishing bob”) shaped glass (Size D-Genius All-Glass).

• Works flawlessly without any use of filter paper or cloth

• Elegant portable design with technical-scientific flair.

• Heating phase generates steam to push water up to mix with coarse grinded coffee beans .

• Cooling down phase generates vacuum to suck extract past the filter back into lower bowl.

• Coffee is prepared at optimal temperature

• Ready to pour in 6 minutes (use pre-heated water).

• Heat source works on common fire/cleaning spirit (other names: denatured, methylated alcohol).

• Made in Europe with durable materials and no parts that wear.

• Fire-proof laboratory quality borosilicate glass elegantly formed.

• Solid metal stand with chromium and high-gloss black accents.

• Aperture in stand to place upper bowl into rest-position once you are ready to pour.

• Solid bakelite black high-gloss handle has pleasant grip for both right- and left-handed users.

• Available in two variants: ‘D-Genius All-Glass’ (pragmatic choice for home users) and ‘D-Genius Precision-Weave’ (alternatively equipped with our 30 micron ‘Precision-Weave’ metal sieve filter).

• One size "D" =  1.14 liter = 38.5 oz. Serves 8 large cups or less.