Distilling water with a coffee syphon

[Mark the Box Guy]

DEBUNKED: see later posts.

I'm now using my coffee syphon to distill water for lye. For many years, university lecturers have revered the powerful impact that a proper coffee syphon can have on grading awful essays. Clarity and objectivity are preserved because these bizarre devices brew perfect coffee by 1) using distilled water, and 2) by ensuring that the water never rises above boiling. It's a fine cup of coffee. Logic dictates that it can also be used to distill water quickly and simply.

Now I'm using it to make soap.

My local market doesn't sell distilled water, and British water is notoriously hard, so I've used my syphon as a simple home distiller.

For the unfamiliar, the bottom chamber holds tap water. As the water simmers, the vapour travels up the tube into the upper chamber, where it cools and becomes liquid. The now-distilled water is held in the upper chamber by a spring-loaded cap/filter until the bottom chamber cools. The pressure difference between the two chambers equalises as the bottom chamber cools, releasing the spring and allowing the distilled water to flow back down through the tube. Rather than allowing the distilled water to mix with the undistilled water in the lower chamber, I simply remove the upper chamber and place it over a pitcher, which rapidly fills with my now distilled water.

Now I have distilled water for my lye.

The instructions are simple:

1) Fill bottom chamber and assemble the syphon.
2) Place the entire affair upon the stove and turn on the heat.
3) After several minutes you'll notice that the top chamber is filling.
4) You must work quickly once the top chamber is filled to remove it from the assembled device (a simple process requiring gloves or a kitchen towel) and place it over your pitcher.
5) Watch in amazement as the pressure equalises and the distilled water whooshes down the tube, ready for your lye.

 

[lsg]

That is an interesting post. About how much water can you distill each time?

 

[Mark the Box Guy]

That is an interesting post. About how much water can you distill each time?

Several companies make them in several different sizes. Take a look on Amazon.

They also make a great cup of coffee, and should be perfect for tea. The entire process takes 10 minutes.

 

[DeeAnna]

I have a vacuum coffee maker and love it too, but I have to burst your bubble, Mark -- the water is not distilled. All you are doing is transferring liquid water from the lower chamber to the upper by virtue of increasing the vapor pressure in the sealed lower chamber. It makes great coffee, but it is not distilling the water.

Have you ever boiled a pan of water to dryness and had to scrub away the mineral stuff left behind in the now-empty pan? When the water boils in the pan, it turns into vapor (steam). The vapor leaving the pan is pure water, because the unwanted minerals can't boil away and are left in the pan. If you can collect that water vapor, condense it back into liquid form, and keep it totally separate from the remaining liquid water in the pan -- now that is distilled water.

Rain water or dehumidifier water is more-or-less distilled, since this water has also been condensed from water vapor in the air so it has few or no minerals in it. The problem with these sources of water is that water vapor is not the only thing in the air. Bacteria, fungi, dust, air pollution, and pollen are also in the air and can end up in the condensed water, so rain water and dehumidifier water might not be something you would want to drink straight off.

Just leaving rainwater or dehumidifier water to quietly settle in a container will remove most of the particulates and will probably be good enough for soap making. Fine filtration and disinfection will often finish the job if you are wanting this water to drink.

I should add, in areas with heavy air pollution, there will be some dissolved pollutants (acids, for example) that cannot be removed without special chemical treatment (carbon adsorption, reverse osmosis, etc.), so drinking this water might not be the best idea without further study.

--DeeAnna

 

[Mark the Box Guy]

If you can collect that water vapor, condense it back into liquid form, and keep it totally separate from the remaining liquid water in the pan -- now that is distilled water.

I am only using the water from the upper chamber. I'm not allowing the water to run back down into the as-yet-unvaporised water in the lower chamber.

By removing the upper chamber to drain into the pitcher, I'm only using the water created by the condensed vapor. That water has been distilled, and the deposits are left in the lower chamber, which is discarded.

I've never seen a column of water rise up through the tube. In my experience, only vapor/steam rises through the tube into the upper chamber. This is evident in the photos. Perhaps other syphons, with smaller tubes, push water up, but mine certainly doesn't.

 

[DeeAnna]

Your coffee maker is a regular, normal vacuum coffee maker, just like mine. The photo clearly shows the tube from the upper chamber that extends down into the liquid water. The lower tube is there specifically to force only liquid water to rise from the lower chamber into the upper.

When you heat the water in the lower chamber, some water vapor is created in that chamber. Because that chamber is tightly sealed, the pressure increases. This pressure is allowed to do only one thing -- force the liquid water to rise up the open tube from the lower chamber into the upper chamber. The liquid water then blends with the ground coffee in the upper chamber.

When enough of the liquid water rises, the lower end of the tube finally becomes uncovered. This allows a small amount of water vapor to bubble into the upper chamber. It's purpose is to mix the coffee grounds with the hot liquid water. After a suitable mixing time, the entire pot is removed from the heat source and allowed to cool.

Edit:

Okay, I'm back for a clarification.... You are finishing the "distillation process" by putting the upper container on a third, separate vessel and allowing the liquid in the upper chamber to flow down into that vessel.

The question of whether the water in the upper chamber is distilled or not is determined well before that point.If LIQUID water flows up the tube, the water in the upper chamber is not and can never be distilled water; it is just hot water that is being moved from place to place.

The water in the upper chamber is distilled water if ONLY water vapor flows up the tube and is condensed in the upper chamber. Since the water in the upper chamber is not condensed water vapor, it doesn't matter whether that water flows back in the lower pot or is put into a separate vessel. It is still not distilled water.

End edit. Back to my original post...

Okay, that is my understanding of how this type of coffee maker works. It's a fascinating and elegant physics experiment, and I love the whole process, especially since it makes great coffee as well as provides a great show.

Going with your understanding, only water vapor is allowed to rise into the upper chamber. If this is indeed true, then all the water boiling into vapor in the lower chamber will create a HUGE volume of vapor in the upper chamber. (One milliliter of liquid water will expands well over 1000 times when it turns into water vapor at normal atmospheric pressure.) All of that vapor will have to be contained and condensed in the upper pot in order to make the coffee.

There is no way this type of coffee pot is designed to handle all of that expansion and condensation ... nor does it need to, so I must continue to politely disagree with your perception of the process. But, as always, YYMV. Although I am an engineer and former college science instructor, I do concede that am misinformed on a regular basis.

 

[Mark the Box Guy]

[/B]Okay, I'm back for a clarification.... You are finishing the "distillation process" by putting the upper container on a third, separate vessel and allowing the liquid in the upper chamber to flow down into that vessel.

The question of whether the water in the upper chamber is distilled or not is determined well before that point.If LIQUID water flows up the tube, the water in the upper chamber is not and can never be distilled water; it is just hot water that is being moved from place to place.

The water in the upper chamber is distilled water if ONLY water vapor flows up the tube and is condensed in the upper chamber. Since the water in the upper chamber is not condensed water vapor, it doesn't matter whether that water flows back in the lower pot or is put into a separate vessel. It is still not distilled water.

End edit. Back to my original post...

I do, and have always agreed with your evaluation. I've never thought otherwise. Boiled water is not distilled water; only condensed vapor is.

But: I've never seen a column of water move to the upper chamber. I've only seen vapor, and frankly, I've never watched it closely. That's why I thought that the syphon distilled; I have always thought that I saw vapor. I will certainly watch my next pot of coffee very carefully, because I'll try and make whisky if I only see vapor. :twisted:

thanks,
m

 

[DeeAnna]

"...I've never seen a column of water move to the upper chamber. I've only seen vapor..."

I am truly puzzled now, and I am not trying to be snarky in any way. The stuff in the lower chamber, upper chamber, and tube that my arrows are pointing to is liquid water to me -- it is not water vapor. Are we using the same language to mean different things?

 

[Mark the Box Guy]

We're using the same language. I'm certain of it.

I've used this syphon about a half-dozen times since receiving it for Christmas. When it was described to me, and when I read about it, the word vapor was used. I never questioned it, and never examined it closely. It looked like vapor, so that's what I've continued to think. I never really questioned it until now.

But you seem confident enough (and you are an academic, as am I,) so I'm required to question my observation, which I'll do tomorrow morning, when I run a test. I'll place brewed tea (a dark color) in the bottom chamber and repeat the process. The tube will either be filled with dark liquid (indicating water and no distillation) or it will be clear/steamy (indicating vapor and distillation.) This will put the matter to rest for me.

I sincerely hope that you don't consider this an argument, because I certainly do not. I find this interesting, and am learning a great deal from your responses. I'm a social scientist, not a chemist or engineer. However, when I have a question I doggedly pursue a dispassionate answer. I simply want to know the truth.

 

[Lotus]

You guys are so polite! I love it. If only most discussions with apposing views were so polite!!

My father has a vacuum pot. He swears by it, and it does make an excellent pot of coffee. The novelty of this type of coffee making (for you coffee snobs out there), is that the water and coffee never touch anything but glass (although there are some models out there with plastic components, defeating the whole point, in my opinion), which is the only material which can't affect the taste of the liquids, therefor making an arguably perfect cup of coffee, where the essence of the coffee is truly realized.

I'm excited to see the results of your experiment, tomorrow, Mark.

Edit: I wanted to show you a link with a picture of the type my father has. Here it is:

http://stumptowncoffee.com/brew-guides/vacuum-pot/

 

[DeeAnna]

Lotus -- Actually my vacuum pot is stainless steel and dates to the 1950s or thereabouts. I used to have an old glass pot similar to Mark's, but I managed to break it. Stainless works better for fumble-fingered me, but it's not as fun to watch. It works the same way, though.

"...I sincerely hope that you don't consider this an argument..."

I have been sincerely hoping you didn't either. It's not my intent to argue, just to figure things out in a civil, friendly way. If you're game, so am I!

This conversation reminds me of my past. Many of the (overwhelmingly male) engineers I used to work with were of the "if we raise our voices and argue vehemently, we must therefore be right" persuasion. I only lasted about 10 years in the corporate engineering world. I was (and still am) a good engineer, but my voice just wasn't loud enough, both literally and figuratively, to cut it in big-business engineering.

I was happier and more effective as a college instructor. I wish I had thought to show a vacuum coffee maker to my physics students. That would have been a cool lab experiment for studying the concept of vacuum, pressure, and the "ideal gas law". I don't teach nowadays, and I miss it.

"...This will put the matter to rest for me...."

Yes, I agree this should be the proof of the pudding. I too am curious how your tea experiment will turn out -- that is an elegant idea and I applaud you for thinking of it.

 

[Lotus]

[/FONT]This conversation reminds me of my past. Many of the (overwhelmingly male) engineers I used to work with were of the "if we raise our voices and argue vehemently, we must therefore be right" persuasion. I only lasted about 10 years in the corporate engineering world. I was (and still am) a good engineer, but my voice just wasn't loud enough, both literally and figuratively, to cut it in big-business engineering.

Oh! This so explains my husband's uncle (a weapons engineer for the Department of Defense), who has a way (well his whole family, really) of not listening to a word anyone says, and just speaking his point of view over anything you might be saying. Just no pause. Just that kind of "you have no choice but to listen to what I'm saying, because I'm not going to stop talking" mentality. Much like some callers on a radio talk show.

ETA: It was the weirdest experience to me (an experienced, attentive conversationalist), when they came to visit last summer.

 

[DeeAnna]

Yes, Lotus, that sounds familiar.

 

[Mark the Box Guy]

Well it's official: the syphon does not distill water. What I thought was vapor, was in fact a cleverly disguised column of water. The photo clearly shows an identifiable brown column of tea moving from the lower chamber to the upper.

I'll have to pickup one of these instead: http://www.copper-alembic.com/ns/product.php?id_product=37

 

[Skatergirl46]

Here's something that would distill water and it's a pretty simple contraption.

 

[DeeAnna]

Well, now we all know for sure! Thanks for doing the experiment, Mark. It's always satisfying to learn by doing, at least for me. It sounds like you are serious about making your own distilled water -- bravo for you!

 

[Mark the Box Guy]

Well, now we all know for sure! Thanks for doing the experiment, Mark. It's always satisfying to learn by doing, at least for me. It sounds like you are serious about making your own distilled water -- bravo for you!

All of this backyard chemistry is too much fun to ignore. :grin:

 

[Skatergirl46]

All of this backyard chemistry is too much fun to ignore. :grin:

I agree! I love it when science and art come together.

 

[DeeAnna]

The water kettle and carboy (jug) gizmo would work, but the carboy needs to be cooled better by running water over it or keeping it in a cold water and ice bath. If you count only on the surrounding air to cool and condense the water vapor, as shown in the photo, the process will be very inefficient.

A warning -- At least one end of the tube between the kettle and the carboy must be a "loose" connection so excess pressure can easily bleed off into the room air. If you do make hard connections, the pressure in your impromptu distillation unit will build up if your cooling is not precisely controlled. You might have a very interesting time, to put it mildly. :thumbdown:

I do have to wonder about the overall cost of doing this -- is the time and energy spent going to be worth the trouble?

<musing> Of course, I imagine someone could ask the same question about making soap by hand.

Neverrrrr mind.....