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Vacuum coffee maker

Vacuum coffee maker is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Vacuum coffee maker rather than just read about it. In short: A vacuum coffee maker brews coffee using two chambers where vapor pressure and gravity produce coffee. This type of coffee maker is also known as vac pot, siphon or syphon coffee maker, and was invented by Johann Nörrenberg in 1827.

Vacuum coffee maker — main illustration
Vacuum coffee maker — illustration

Key takeaways

  • Vacuum coffee maker belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Vacuum coffee maker to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Vacuum coffee maker from memory before moving on to harder problems.

Reference excerpt

A vacuum coffee maker brews coffee using two chambers where vapor pressure and gravity produce coffee. This type of coffee maker is also known as vac pot, siphon or syphon coffee maker, and was invented by Johann Nörrenberg in 1827.

History and design Since their invention these devices have been used in many parts of the world. While vacuum coffee makers generally were excessively complex for everyday use, they were prized for producing a clear brew, and were quite popular until the middle of the twentieth century. Vacuum coffee makers remain popular in some parts of Asia, including Japan and Taiwan. Design and composition of the vacuum coffee maker varies. The chamber material is borosilicate glass, metal, or plastic, and the filter can be either a glass rod or a screen made of metal, cloth, paper, or nylon. The Napier Vacuum Machine by James Robert Napier, presented in 1840, was an early example of the vacuum brewing process. The Bauhaus interpretation of this device can be seen in Gerhard Marcks' Sintrax coffee maker of 1925.

Balance siphon An early variation of this principle is called a balance siphon or Belgian brewer. This implementation has the two chambers arranged side by side on a balance-like device, with a counterweight attached to the heated chamber. Once the vapor has forced the hot water out, the counterweight activates a spring-loaded snuffer which smothers the flame and allows the initial chamber to cool down thus lowering pressure (creating a vacuum) and causing the brewed coffee to seep in.

Automated version In 2022, the Japanese Tiger Corporation released an automated coffee-maker based on the vacuum coffee maker principle, which was marketed as the Siphonysta. The Siphonysta's heating is electrical. The chambers are made of plastic ("resin").

Brewing principle

A vacuum coffee maker operates as a siphon, where heating and cooling the lower vessel changes the vapor pressure of water in the lower, first pushing the water up into the upper vessel, where the coffee is brewed, then allowing the brewed coffee to be strained as it is drawn back down into the lower vessel. Specifically, by heating (A) the water in the sealed lower vessel (B), the combination of its vapor pressure (the pressure exerted by the vapor component of a liquid) and the pressure from heating the air will exceed the ambient standard atmospheric pressure, causing some of it to boil, turning into water vapor. Since the density of water vapor is approximately 1⁄2000 that of liquid water, the mixture of air and water vapor in the lower vessel quickly expands as more liquid is boiled to vapor, increasing the pressure in the lower vessel.

Once the pressure in the lower vessel exceeds atmospheric pressure, the remaining water is pushed up through the siphon tube (C) into the upper vessel (D), where it remains, so long as the pressure difference between the upper and lower vessels is sufficient to support it, about 1.5 kPa (0.015 atm). This pressure difference is maintained during brewing through the continuous heating of the lower vessel. Coffee grounds are added to the water in the upper chamber and coffee is brewed using the displaced water at slightly less than the boiling point, 100 °C (212 °F). When the coffee has finished steeping, the heat is removed and the pressure in the lower vessel decreases; when the combined force of gravity and atmospheric pressure overcomes the (decreased) pressure within the lower vessel, the brewed coffee is pulled into the lower vessel of the vacuum coffee maker, leaving the coffee grounds in the upper vessel. The moka pot coffee maker functions on the same principle but the water is forced up from the bottom chamber through the third middle chamber containing the coffee grounds to the top chamber which has an air gap to prevent the brewed coffee from returning downwards. (Additionally, because the water is forced up through packed grounds, the pressures are greater.) The prepared coffee is then poured off from the top.

See also Coffee portal Minto wheel Bodum, makers of the Santos, Pebo and ePebo vacuum coffee makers

References

External links Vac Pot How-To pdf Siphon brewer in operation, Sydney Australia

Illustrations

Vacuum coffee maker: A vacuum coffee maker. Industrial design-classic by Abram Games.
A vacuum coffee maker. Industrial design-classic by Abram Games.
Vacuum coffee maker: Vacuum pot coffee brewer: vapor pressure forces the water into the upper chamber.
Vacuum pot coffee brewer: vapor pressure forces the water into the upper chamber.
Vacuum coffee maker: As temperature increases, the vapor pressure of water increases. At the normal boiling point of 100 °C, the vapor pressure equals the standard atmospheric pressure of 760 Torr (760 mm of mercury).
As temperature increases, the vapor pressure of water increases. At the normal boiling point of 100 °C, the vapor pressure equals the standard atmospheric pressure of 760 Torr (760 mm of mercury).
Vacuum coffee maker illustration
Vacuum coffee maker illustration

Worked examples

Example 1 — a first encounter with Vacuum coffee maker

Start with the simplest possible case. Write down what Vacuum coffee maker claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Vacuum coffee maker before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Vacuum coffee maker ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Vacuum coffee maker

In research
Vacuum coffee maker appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Vacuum coffee maker in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Vacuum coffee maker is common in secondary-school and first-year university syllabi. It links to neighbouring topics Coffee preparation, Coffeeware, Fluid dynamics, so understanding it makes those chapters shorter.
In everyday life
Look for Vacuum coffee maker outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Vacuum coffee maker in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Vacuum coffee maker means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Vacuum coffee maker out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Vacuum coffee maker in simple terms?

A vacuum coffee maker brews coffee using two chambers where vapor pressure and gravity produce coffee. This type of coffee maker is also known as vac pot, siphon or syphon coffee maker, and was invented by Johann Nörrenberg in 1827.

Why does Vacuum coffee maker matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Vacuum coffee maker?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Vacuum coffee maker.

Tags

  • Coffee preparation
  • Coffeeware
  • Fluid dynamics
  • Vacuum

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