19 Apr 2015

Tutorial: How to Brew Vacuum Pot Coffee

25 grams | 300 ml | 100C | +/- 2:30 minutes

The vacuum pot, ain't they grand? Known as vac pot, syphon or siphon, and to some as a cona, it has been around for some time. It is a system that uses two different chambers where the combination of vapor pressure and vacuum produce a brew. The first patent was filed by Loeff of Berlin in the 1830's. However, the French Marie Fanny Amelne Massot (aka Mme. Vassieux) was the first one to design and patent the first commercially successful vacuum pot in 1840. 

They are used in the coffee industry, where the Hario syphon is the best known device, but are also very commonly used to make cocktails and broths. 

They can be quite expensive, but they produce a very clear and bright brew, plus they look very impressive on the dinner table. Depending on the filter, there are some differences though. And an array of filters there are, ranging from a glass cone, to a screen made of metal, cloth, paper or nylon. All will result in different flavours. A metal or glass filter will give more body and less brightness, where a cloth filter will create a very clean tastes with more thin body.

As I have a cona in my collection, we are brewing with a glass filter today. A positive note, it does not transfer any flavour to your brew,
but it can leave a little coffee ground residue in your cup.

If you would rather see a shortened tutorial in video format, check out the Coffee Strides channel on Youtube.

What will you need
- 8,4 grams of coffee beans per 100ml of water
- filtered water
- kettle and pouring kettle (optional)
- scale
- timer
- grinder
- vacuum pot and heat source
- something to stir with

step 1
Weigh out your coffee. As mentioned above you will need 8,4 grams of coffee per 100ml. You need quite a high ratio of coffee to water, because your extraction time is generally relatively short. When experimenting yourself, do try different dosages. You will want to grind a little finer for a paper or cloth filter, which can mean you might want your ratio to be even a little bigger. 


step 2
For a metal or glass filter you want to grind to a medium-coarse to coarse grind, because you do not want the grounds to travel past or through the filter. For a paper or cloth filter you can go a little finer. If you want an overview of different grind sizes, check out this overview

If you are indeed using a cloth or paper filter, make sure to wetten them through before use.


step 3
Now, you want to heat up water in the bottom chamber of your vacuum pot. You can either start with cold water, but unless you have invested in some powerful heat source, it is a lot quicker to start with boiling-to-near-boiling water. Because of the heat, pressure will start to build up in the bottom chamber and this pressure will start to push the water up into the top chamber. Quite like an espresso pot. As the bottom chamber heats up and pushes the water and oxygen away, a vacuum will be created.



step 4
Once almost all the water has travelled up, it will start bubbling in the top chamber. Now, there will always be some water left in the bottom chamber. This is normal. Soooo, no worries. 

When the water starts bubbling, you can add your ground coffee to the top chamber. Sometimes you will see people adding the grounds before the heated water travels up. This will result in more bitter flavours, because of a longer extraction period. Some claim this more bitter flavour might also have to do with the fact that the water boiling up is really, really hot and will 'burn' your grounds. If you wait, the collected water will be a little lower in temperature. Whether this is the case, not sure. But I do know I like my brew better, when waiting to add the grounds till all the water has bubbled up into the top chamber.



step 5
After adding all your grounds, stir them through the water a couple of times. Set your timer for 45 seconds.


step 6
After the 45 seconds are up, remove the heat source and stir again until you see that water starting to travel down again. The cooling of the bottom chamber, which is under vacuum, will pull your warm brew back down again. Your brewed coffee will end up in the bottom chamber and your grounds will be blocked by your filter in the top chamber.


step 8
Once you see the brewed coffee bubbling in the bottom, your brew is done!




step 9 
Now the brew is all collected in the bottom chamber, you still need to break the vacuum. Meaning that removing the top chamber needs a (little) bit of force.




Step 10
Now you are all done, so all that is left to do is enjoy your bright and clean brew.

Do remember, if you have a cloth filter, to immediately rinse out the cloth. Store your cloth in cold water if you use it often. If not, you can keep it dry, but make sure to wetten the cloth thoroughly before the next use. You can use your cloth filter up to 6 brews.


Check my other brew tutorials and recipes here.

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