Vacuum pot brewing

[phaelon56]

Thanks to the eagle eye of Rachel Perlow, who is always spotting good bargains on Amazon (use your eGullet link please!), I recently acquired a Bodum vacuum pot coffee maker. This is a totally manual operation that requires an external heat source to boil the water. Bodum, one of the leading manufacturers of vac pots, offers an electric version in two sizes as well. Many of you have likely seen an electric vac pot for sale at your local Starbucks as well.

Vacuum pot coffee brewing has been around for a long time - since the 1840's. It's believed to have been developed in France (figures). I believe its real heyday was in the 1930's through the early 1950's. The introduction of the electric percolator (an insult to lovers of good coffee everywhere) appears to have hastened its retreat to semi-obscurity, just as the appearance of the original Mr. Coffee auto drip maker pushed the percolator into the dustbin of history.

Vacuum brewing has made a well deserved comeback due to the relative ease of operation and the quality of the coffee it produces. There appears to be a bit of renewed interest in electric percolators as well but I'll hope that goes the way of the brief resurgences of disco music and bell bottom trousers - some styles should stay where they are.

Popular brands include Hario, Cory and Bodum. The method of filtering ranges from cloth to glass rod to plastic mesh. Older vac pots are considered highly collectible and see great interest on Ebay. You may find one at a yard sale or thrift store - check carefully to ensure that any and all rubber gaskets are present and not cracked or deteriorated. In many cases replacement gaskets are available but it could drive up the cost of your "bargain".

So, with $39.95 invested and a bit of Jamaican Blue Mountain taken from the freezer and thawed, I set out to put this gizmo through its paces (the coffee was a birthday gift from my parents - pre-roasted and fresh enough but I froze it right away for later use as most of my coffee consumption is in the form of espresso). I should add that I was shamed into doing this by Mayhaw Man, who diplomatically pointed out that, in another thread, I had promised to do this post haste and still hadn't delivered. I owe him for that great blog but I also just needed a kick in the pants to get started.

Here's the gear filled up with water and ready to go - the vertical black cylinder supporting the upper pot on the right is just used to "park" the upper pot on the counter when necessary, due to the glass rod assembly that protrudes below the pot.

On the stove and firing up. The very limited instructions advised that a separator ring was recommended for gas stoves to ensure safety of the glass pot but I've seen elsewhere that it's suggested only for electric stoves. I just put the darn thing right on the burner and kept the gas at medium. I used a bit more than one standard coffee scoop of grounds per 6 ounces of water and used a medium fine grind - about what you'd use for auto drip coffee or perhaps just a tad coarser. I may use a bit more coffee next time. The grind should be a bit finer than one uses for French Press but use your judgment - if using a blade grinder you may have to go coarser than I did to avoid coffee dust in your grind. The fine powder sometimes yielded by blade grinders could clog the filtering arrangement and impede the movement of the coffee. It is recommended that the top should not be added until the water is almost at the boil. I was unaware of this at the time and left the top on the entire time but it seems to have worked just fine anyway.

In the next photo we see the water heading north. It has boiled and the vacuum pressure created in the lower pot has caused it to head up the glass filter tube and settle in the upper pot. It's a great concept - the water rises when it boils, passing through the coffee and settles in the upper pot at just below the boil - the ideal temp for brewing. A bit of water remains in the lower pot because the glass syphon tube does not contact the bottom - there's about 1/4" of clearance. The water remaining in the lower pot will mix later with the finished coffee. It's recommended to leave the grounds and water in contact with one another for one to three minutes - then remove from the heat.

Some suggest breaking up the grounds that float on the surface when the water first appears in the upper pot, just to ensure that they're evenly dispersed but this is personal preference. The bubbling that is visible in the upper pot is the vapor that's emerging from the vacuum in the lower portion of the pot - it is NOT boiling! Recirculating boiling water through the coffee grounds repeatedly is how percolators do their nasty and reprehensible thing - yuck. I don't like percolator coffee.... can you tell?

After being removed from the burner (Bodum provides a sort of plastic sleeve/trivet assembly that the pot can be placed in after removing from the heat), it's placed at room temp on the counter and the coffee quickly begins its trip south to the lower pot, leaving the grounds in the upper pot. This happened very rapidly with my first attempt - probably a sign that I didn't grind finely enough.

Okay - now we have a pot of coffee - appears to be very full bodied like French Press coffee with lots of coffee oils included.

The test is in the cup (my favorite coffee mug)

After all this hoopla... how did it taste? Delicious. I tested it black before adding half 'n half and it was indeed a very smooth and full bodied cup of coffee. My reference point is having recently made this same coffee (JMB) with a Melitta manual drip filter cone. The vac pot coffee seems fuller bodied but doesn't quite have that sometimes overwhelming presence of oils and aromatics that is more typical of French Press coffee. This initial test has been promising. I drink French Press coffee on rare occasions and often find it to be just a bit much for my liking. The vac pot method appears to yield most of the advantages of press pot coffee but minus the sludge.

I need to do more testing but the cup was extremely satisfying and it's a very cool process to watch. There are some fancy vac pot sets on the market (some Hario models among others) that use a spirits burner and may be placed on the dining table to brew the coffee and entertain your guests. It's a fascinating process and I can see the appeal although it's less convenient than some other methods. It's worth mentioning that cleanup was a cinch - I just rinsed the grounds down the drain and put the two parts of the assembly in a dish rack to dry.

If you remain intrigued and wish to know more.... everything you ever wanted to know about vac pot coffee (and even stuff you probably don't care about) may be viewed at

Coffeekid.com - personal web site of Coffeegeek founder Mark Prince

He has some good tips and hints on buying used vac pot gear as well as a detailed discussion of the history of vacuum coffee brewing.

[Mayhaw Man]

I should add that I was shamed into doing this by Mayhaw Man, who diplomatically pointed out that, in another thread, I had promised to do this post haste and still hadn't delivered. I owe him for that great blog but I also just needed a kick in the pants to get started.

Thanks for taking the time to do this. I am sorry that I had to publicly embarass you in order to get you started.

There are some fancy vac pot sets on the market (some Hario models among others) that use a spirits burner and may be placed on the dining table to brew the coffee and entertain your guests. It's a fascinating process and I can see the appeal although it's less convenient than some other methods

That's me. I'm there. I'm going hunting for a cool new vacuum rig in the Amazon right now!

[phaelon56]

Thanks for taking the time to do this. I am sorry that I had to publicly embarass you in order to get you started.

That's me. I'm there. I'm going hunting for a cool new vacuum rig in the Amazon right now!

Some of the finest events of my life have been kick started by public embarassment but we needn't go there

Hunting in the Amazon? Sounds tres kewl....

[phaelon56]

It's not as though I needed more caffeine today but it is a weekend...

In the interest of science I made another vacuum pot batch. This time I used the ratio that Mark Prince mentioned on his Coffeekid site: 3 tablespoons of coffee for 15 ounces of water. By chance he mentioned the weight - 23 grams (thank you Mark!). It is really so much easier to replicate results when weight to water ratios are established.

I also took care to wait until the water was nearly at the boil before adding the upper pot, stirred once to scatter the coffee that rose onto the surface once most of the water was up, and then let it steepl with a low boil in the lower pot for exact.

Damned if it wasn't one of the best cups of coffee I've had in years.... literally the best. Every variant of coffee preparation has its merits and attractions... drip, moka, espresso.... but this will completely replace auto-drip and Melitta manual cone drip for me. I think the time may soon approach when I'll pick up an electric auto-vacuum pot but for now this little Bodum is the bomb.

[Cynthia G]

I've been thinking about finding a new way to make coffee while camping. Owen, do you think this could be used on a wood fire with a grate?

[phaelon56]

Yes... I think so if you're careful with it but the general consensus among camping folks I've spoken with is that moka pots or a press pot are the way to go. If you can handle the bulk of bringing somethign like this with you, I think the pot can handle the heat - I'd suggest not getting it too close to the coals but it should work. It does make one hell of a great cup of coffee.

[Cynthia G]

Thanks. Not really pleased with the press pot.... so perhaps this is the thing I've been looking for.

My circle generally takes their horses up into the Pecos Wilderness and usually have an animal just to pack things in.... no trouble with transporting!

[phaelon56]

Further testing this morning. Bumped up the water to 25 oz and the coffee to about 35 grams. That appears to be about a maximum batch for this size of brewer (they are available in larger sizes). The amount of time required to "travel south" back into the lower pot was slower - a shorter steep time before reducing the heat would have been appropriate. As instructed by Bodum, when the downward migration appeared close to stalling, I placed the assembly back on the heat momentarily. One quick bubble of the coffee and the rising vapor cleared the tube for the remaining coffee in the upper pot to continue its journey.

This should be done only if absolutely necessary and for just a few seconds as causing the coffee to boil wil ruin some major flavor components.