Coffee Cup
"Espresso! My Espresso!"
An Ongoing Internet Novelette
by Randy Glass - Copyright 2003 - All rights reserved

Coffee Cup
Coffee Making Methods
- Vacuum Pot -

      These chapters were originally written for my newspaper as part of an somewhat-monthly coffee column. They were designed to expose the coffee novice as to the various methods of making coffee and act as a starting point for understanding these methods. If you have been making coffee by any of these methods for any length of time then you will probably not find anything in these chapters to enlighten or educate you. Please feel free to E-mail me with anything that you think could be improved in these methods. -ED


     A forgotten method of making coffee in today's society is the vacuum method. The "modern" percolators of the 50's, particularly the self-contained electric pots, ended the long reign that the vac pots had as far as creating a rich, full-flavored cup of coffee. Names like Silex, Cory, Kent and others were common. I have been told that during WWII, most naval ships packed a few cases of these pots for use in the officer's mess. Why cases of them? For the most part they were made from glass and as the glass was thin and treated to be heat resistant making it quite brittle. One bang against a counter or a drop into the sink, and the pot was in pieces.

Let's take a look at how a vac pot works

     All vacuum pots have three basic elements. you begin by measuring an amount of water out and placing it in the lower bowl. This is placed on a heat source which might be a stove top, electrical hot plate, or over an alcohol burner. While the water is heating in the lower bowl, the upper half is assembled.

     The upper half has two parts. The vessel itself with a tube extending under it (all one piece) and a filter assembly. The filters can be made from one solid piece of glass (a filter rod as shown here) or they sometimes have a holder that locates a cloth filter. Once the filter is in place in the upper bowl the ground coffee is added. One thing that all vacuum pots have in common is that they like a fairly coarse grind of coffee.

     About now the water in the lower bowl should be ready to boil. Once the water shows signs of that, the upper bowl can be placed onto the lower bowl and the brewing process begins. The example above is an old Cory pot.

     The lower chamber is now sealed except for the tube which leads into the upper pot. The boiling water creates steam and this increasing pressure makes the water want to leave the lower pot. The only place it can go is to force its way up through the tube and into the upper bowl where the rising water agitates the water and coffee together. Once there you give it a bit of a stir to be sure that all the grounds get mixed into the water and then you wait for about two to four minutes (depending on your preferred coffee taste) and the entire assembly is removed from the heat source and the lower chamber begins to cool. The cooling causes a low pressure to develop in the lower pot (a vacuum) and the water is sucked back down into the lower pot through (or around) the filter. This further extracts coffee flavor from the grounds and filters out most of the coffee grounds themselves.

     When the coffee has returned to the lower pot, the two halves are separated and the lower chamber becomes a serving vessel. here you see that the lid on top of the upper chamber has a protruding tube built into the top of it. This lid is placed on the counter and the upper bowl's tube rests in the lid when the upper pot is removed from the lower. This allows it to cool and rest safely while the coffee is being served.

     The greatest benefit of the vac pot is the control over the temperature of the water. As it rises from the lower boiling pot the water cools just enough as it rises (it cools to below the boiling point or around 200-205 degrees) to be at the perfect temperature for making coffee. It is just hot enough to remove all the best of the flavor elements but not so hot as to boil the coffee or extract the more bitter elements. The pulling of the coffee through the grounds as the vac extraction finishes also adds to the flavor.

     To further control the process, the user can modify the procedure by not adding the coffee until all the water has entered the upper bowl. At that point the coffee is added, stirred a bit, and then after a user-desired amount of time the heat source is removed and the coffee's journey south begins. If the coffee you have been making in your vac pot has been tasting over-extracted, use this method to limit the amount of actual brewing time.

     Vac pot makes a delicious brew and it's hard to imagine why they are not still in widespread use. For decades, from about the late 20's or so through the fifties, vacuum coffee was the best and most widely used ways there was available for most folks to create a delicious cup of coffee. Percolators were available but their brew pales in comparison to vac pots. Although a vac pot makes a really great cup of coffee they do tend to leave a bit of sediment in the pot and depending on how carefully you pour, some gets into the cup. Just don't take that last sip!

     Although the days when the vacuum pots ruled the coffee-making world are gone, vacuum pots are still available. They come in various sizes and price ranges. There are also a number of various brands and models available on the Internet. I prefer the glass pots if for no other reason that it is fun to watch the hot water move upwards and the finished coffee making its southward journey. Old vac pots show up on E-Bay all the time but prices run from $30 to well over $100 for these, but parts like the rubber gaskets for most of these are no longer available. Here are lot of pictures of old vacuum brewers. For more information do a search for "vacuum coffee pot" or "coffee syphon" on the Internet.



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