Silex Vacuum Coffee Maker

The Silex brought the vacuum coffee maker into American kitchens. Launched in 1915, it’s a two-bowl glass brewer: water boils in the lower bowl, rises into the upper bowl to brew with the coffee, then is sucked back down through a filter when the pot comes off the heat. It became the familiar hourglass coffee maker of the 1930s, had a 7-foot working model at the 1939 World’s Fair, and spawned rivals like Sunbeam’s automatic Coffeemaster. Here’s how it works and what happened to it.

The short version

• A glass vacuum (siphon) coffee maker, sold in the US from 1915.
• Lower bowl heats, water rises, coffee falls back through a filter.
• Hourglass shape by the 1930s, for the stove or an electric heater.
• Rivals included Sunbeam’s Coffeemaster and Farberware’s Coffee Robot.
• Replaced by instant coffee and the percolator, then drip machines.

How does a Silex work?

Proctor Silex describes the principle: water is heated in the lower half of the brewer “until the pressure caused the water to rise to an upper chamber. There it mixed with coffee grounds until it cooled and the pressure changed enough to suck the brewed coffee down to the bottom.”

1. Fill the lower bowl with water.
2. Fit the filter and coffee in the upper bowl, and seat it in the lower one.
3. Heat it on the stove or an electric heater. Pressure pushes the water up.
4. Stir the coffee into the water in the top bowl.
5. Take it off the heat. As the lower bowl cools, the coffee is drawn back down through the filter.

Early vacuum pots weren’t automatic, Driving for Deco notes: you had to stir the coffee and take the pot off the heat yourself for the coffee to drop. For timings and grind, see our full siphon guide.

Where did the Silex come from?

The vacuum coffee maker is European. Proctor Silex says it was invented in Germany in the 1830s; Driving for Deco credits an 1830s patent by Loeff of Berlin, and the first commercially successful design, the twin-globe pot of Madame Vassieux of Lyon, in 1841.

When	What happened	Source
1915	The Silex Company introduces its vacuum brewer to the American market	Proctor Silex
1915	Corning develops ovenproof Pyrex glass, making a shatterproof vacuum pot possible	Driving for Deco
1930s	The Silex settles into the familiar hourglass shape, for stove or electric heater	Driving for Deco
1937	Farberware’s Coffee Robot, a vacuum pot that stirs the coffee and keeps it hot	Driving for Deco
1938	Sunbeam’s Coffeemaster, a fully automatic, chrome vacuum pot	Driving for Deco
1939	Silex shows a 7-foot, fully working glass coffee maker at the World’s Fair	Proctor Silex
1954	Sunbeam launches an automatic percolator	Driving for Deco
1967	Sunbeam ends production of its last vacuum coffeemaker, the C50	Driving for Deco

What happened to it?

Proctor Silex says sales of the vacuum coffee maker were strong “until the convenience of instant coffee became popular”, and that the vacuum model was eventually replaced by the percolator, which in turn flourished “until the 1970s when the automatic drip coffee maker was invented”. The Silex name lives on in Proctor Silex, which today makes drip coffee makers and kettles.

Vacuum brewing hasn’t disappeared, though: Driving for Deco notes that siphon pots are making a comeback as coffee lovers rediscover how good the coffee tastes.

General guidance only. Vintage glass can crack with age, and old electric heaters may not meet today’s safety standards, so check them carefully before use.

Silex vs other methods

• Siphon coffee: the full guide to vacuum brewing, with modern recipes.
• Cona: Britain’s classic glass vacuum brewer.
• Belgian balance siphon: the see-saw vacuum pot.
• Stovetop percolator: the pot that replaced it.

Explore every vacuum method in the vacuum chapter.