Anyone know how these coffee makers actually work?

I am currently working on a new senior project: Redesigning the coffee maker.

I am still in the research phase and looking at all the ways that coffee makers are configured, from how the filter is replaced to where the water is poured in. I noticed that most coffee makers are of the kind where the water reservoir is in the back of the machine and where gravity and heat plays a part in getting the water down into the coils and back up again. How Coffee Makers Work | HowStuffWorks

With the water reservoir in the back, it forces one to pull out the coffee maker from the kitchen counter to access the door on top to pour the water in. I have also seen some “front loading” machines where you access the filter and water reservoir from the front, which I like better. Well, here is my question:

I have found some coffee machines, such as the Black and Decker Spacemaker series, which mounts underneath kitchen counters. Since there is no opening on the top anymore, all entry for water and filter is in the front. In the case of the models I have posted below, the water receptacle even comes out, so that one can refill it and for cleaning. If it is no longer a static vertical well where the water goes down into that “hole”, past the one-way valve and into the heating coils and back up the other end… in the case of this moving retractable water receptacle on the models shown, how does the water “drain out” of it and into the coils? Does anyone have an idea?

I was thinking of buying a used one on Ebay and taking it apart to figure this out, but maybe someone here can save me the expense and time? The only thing I can think of from reading about the features of this particular B&D unit online, is that the water receptacle clicks into place and it must click into something. The photos are from the actual parts of this one unit I found on Ebay and it shows the water receptacle has some sort of valve in the middle inside. Maybe that valve is a one way type, that allows the water to drain when its ready to make coffee? Sorry for the wordiness, folks. Hope I am being clear.

Thanks guys!



It is opened if the reservoir is in position, no matter if the machine is actually making coffee or not. Additionally, there could be a magnetic float indicating the water level in the reservoir, preventing the machine pulling air.

Hi Max2K. Hello Germany! :slight_smile:

So it’s that simple, huh? I thought it was more complicated! What do you mean: “there could be a magnetic float indicating the water level in the reservoir, preventing the machine soaking in air.”. Sorry… I am just not that technical.


It’s a magnetically operated switch, a so called “reed switch” which is activated by the magnet in the float as long as the reservoir is in place and enough water is inside. If the water level sinks below a certain point or the reservoir is removed, the magnet is no longer in place and the switch is deactivated → the machine won’t work. This status should then be indicated to the user, maybe by a flashing light, a sound, whatever.

water flows from the tank into the tube that is heated by a resistance coil that also in some forms the warming tray. There is a one way valve in the line so as the water heats it expands (boils) and is forced up through the spray head onto the coffee. The one way valve then opens and allows anther slug of water to enter the tube.

So basically, if the water receptacle is not in place, the valve inside of the receptacle prevents water from coming out (such as when refilling it under the faucet in the sink)? In other words, what keeps the water inside of the receptacle when it’s being filled?

Once the water receptacle is locked in place, the valve opens up, but it won’t completely drain until the machine is set to make coffee?
Did i get that right? Thanks for the explanation about reed switches. I will have to google that.

Thanks guys.

It’s the same thing now as in a coffeemaker with a fixed reservoir. There, the cold water also won’t run through the machine until you turn it on.

Any ideas so far what to redesign in such a machine? They’re pretty simple, technically spoken and proven for decades. So, I don’t see much room for major enhancements.

Your right, and the single serve thing is coming on real strong too.

There are still some innovations every once in a while, they may not set the world on fire but they still get noticed. A few come to mind;

The Clover, started by a bunch of Stanford engineering grads, a bit pricey at $11,000, they later sold the company to Starbucks for an undisclosed amount.

George Sowden’s SoftBrew, already discussed in another thread.

And the Kone Funnel.

Hmm, i love that George Sowden one, but his concept isn’t new. The concept of pouring hot water into a receptacle with coffee, letting it seep and then pouring through a filter. My mother used to do this every morning with a coffee sock (we are Puerto Rican) but it was a lot more tedious to clean out the cloth sock, I remember as a child. This is a prettier design and more attractive and convenient way to do it. Although, I did read reviews just now on Amazon and of the two reviewers, both said that the grounds actually came through the filter. Maybe they used a fine ground, instead of something coarser? The holes in the steel filter are supposed to be really super tiny. I don’t deny his idea is still creative.

if you see “creative” as short hand for its over priced and works poorly then sowdens brewer is creative.

Ha! Well, what I do like is having that metal insert with the tiny holes (which are supposed to keep all the grounds out of the coffee) and how easy it is to put it and take out, from what I gathered watching the video. It’s better and cleaner than using a coffee sock. I like the aesthetics of it but you are right about it being overpriced. It goes for 60 bucks! You can get a french press for 20.

The aeropress brews a pretty awesome cup of coffee and is somewhere between a french press and an espresso maker in that
it works like a big surringe using pressure to extract the coffee from the grounds quickly.

Works great, but could use a little love on the aesthetic side and the details.

Kevin Wu did a nice spin on this brewing concept as well, here’s his project on coroflot.

OK, as far as I can see, these coffeemakers are becoming trickier to operate and harder to clean :wink: but there was no real advantage for the user over the “old-fashioned” cowboy-style methods, funnels, drip-brewers or french presses in the examples shown.
For the last four years, most of the coffee I consume is made with a Philips Senseo (Senseo - Wikipedia), a single serve coffee maker which is quiete popular in Germany, also due to the fact that coffee pods/pads are available at relatively low prices from different coffee producing companies.

if you think about it all the single serving systems are like the aeropress, with out the steeping but with vastly easier cleanup and operation.

Every single coffee maker you could think of, although it didn’t have one I worked on a few years ago.

And then there’s the $20,000 Japanese coffee maker;

According to the NY Times article, it seems to be more important how expensive the machinery was than what comes out of it :smiley:

This one made me laugh. :laughing:

It’s like it’s saying: DON’T touch me :laughing:

I’ve been to the Blue Bottle in SF with that coffee maker… it is damn good coffee…