Hi everyone, I am new here.

I've recently become infatuated with espresso machines and I've noticed a bit of a problem in the market for these babies.. In a nutshell, there are no decent, affordable options, for the budding coffee connoisseur and that is a rather large market that could be tapped into. Someone who is just beginning their coffee hobby isn't ready to shell out the $4,500+ required for a machine with temperature control, pressure profiling and pre-infusion. These specific features (or some version of them) are essential in order to be able to extract great shots out of a wide range of coffees and to be able to repeat the exact extraction time and time again. Forget people who are new to the hobby for second, most people in general are never ready to shell out that kind of dough for a coffee machine, which is very sad, since there are a lot of people who are very passionate about this stuff.

I am highlighting this problem because I believe I have a solution and I believe the solution could be beneficial to a lot of people. I've been working on a design for an espresso machine that has all three of the features listed above. With these three features come the ability to pull the same shot time and time again because the user will know exactly what was done to produce each shot. There's no guesswork or luck with this design. What you want, you will get.

Unless I'm missing something, the cheapest machines that this triumvirate of features can be found on cost around $4,500+ (for the record, I don't consider most existing lever machines to be capable of pressure profiling in any meaningful sense, because the user has no idea what pressure they are generating while using these machines). The reason these machines cost so much, is because the implementation of these features is extremely expensive on all of the machines that have them. Another reason these machines cost much, is because they're packaged with a bunch of things which, at least a few people, have no use for, but have to pay for anyway. My design includes very basic versions of all of these features, however, they are just as functional as the features of a machine like the vesuvias dual boiler and require only slightly more effort from the user, which I believe to be a very reasonable trade-off, considering the price tag on a machine like the vesuvias. My machine also includes the absolute minimum required to produce fantastic espresso.

A bit about my design:

My design is a lever machine.

Pressure Profiling:
My design uses a spring to generate the widely accepted optimum brew pressure of 9 bar, and a lever can be manipulated to go above or below that pressure at any point in the extraction. The spring can be removed for a "lever-only" mode of operation, or it can be replaced with another spring to generate a different pressure. There is a pressure gauge to indicate the pressure while brewing, so the user will know exactly how much force is required to achieve a specific pressure by looking at the gauge. In this fashion, virtually any pressure profile can be achieved with ease. Pressure profiling is not automatic, like on the vesuvias, however, the pressure profiling with my design is capable of producing the same results.

In case this isn't clear, if a user wanted to achieve a pressure profile that slowly ramped up to 5 bar for the first 1/3 of the shot, ramped up to 9 bar during the second 1/3 of the shot and extracted the final 1/3 of the shot at 9 bar, this could be done by raising the lever to begin the extraction, and manipulating the lever by pushing up with enough force such that the pressure being applied to the coffee starts out very low and slowly ramps up to the desired level in the desired time frame by applying less upward force to the lever as the extraction continues. By the time the user is at the final 1/3 of the shot, the user can fully let go of the lever as the spring will finish the extraction at 9 bar.

Temperature Control:
I use a water hopper to supply the brew water so that the user can pour water of whatever temperature is desired into the hopper and brew with that water. Everything the water comes into contact with can be warmed in a hot water bath of whatever temperature is desired, or can simply be flushed with water at a desired temperature in order to achieve complete temperature control with basic equipment. An optional part of my design involves wrapping a pipe around the brew cylinder & head, so that water can be pumped through this pipe in order to heat up all the equipment that the brew water will come into contact with. Ideally, I want to design a custom water hopper that can be programmed to heat and maintain the water in the hopper at a temperature which is set by the user and will use this water for brewing and will also pump it through the pipe wrapped around the brew head. Until that side project is ready, a temperature controlled kettle and a water pump will be required in order to have temperature control which rivals the convenience of more expensive machines and if that equipment isn't available, temperature can be controlled similar to how it is controlled on the ROK machine which is not ideal, but still extremely effective.

Pre-Infusion:
When the lever is raised, water from the hopper will gently fall onto the coffee. Like many other lever machines, pre-infusion can last as long as desired.

So enough talk, how about a picture or something? I'm no engineer, so I have no technical drawings or anything like that. I've produced a couple sketches that hopefully illustrate effectively how the design will work, which are below. Please don't be too harsh about my sketches, I have no experience with this kind of stuff.

The god-awful sketches:


UPDATE: Thanks to some great advice I got here, I made some renders in sketchup that should give a better idea of what this thing is supposed to look like



Updated my model a bit more:


I noticed a lot of espresso machines have animal sculptures on top so I put a gorilla on top for the hell of it.

A few more notes about my design:

In the sketches there are no dimensions. I figured that the dimensions are going to be based on available materials, so I have created a design that isn't contingent on specific dimensions to work. There is a great deal of flexibility with regard to size of the various components.

The cylinder is drawn a bit out of proportion to the brew head. The cylinder will probably be a bit narrower compared to the brew head. I'm thinking a surface area of ~2" for the piston and inside the cylinder, so hopefully around 60ml of water can be used. Apologies for going imperial->metric, but I'm thinking in terms of PSI when I think about the area of the piston head and diameter of the cylinder. 9 bar~=130 psi, so the piston head will have to be pushed down with ~260 lbs of force to generate 9 bar if the surface area is 2". With a lever that is ~10x longer than where it pivots, about 26 lbs of force should be required to lift the lever in this case. I believe something in this ballpark is acceptable for most people.

The brew head is a small ring that screws on to the bottom of the cylinder. The purpose of this small attachment is to make my design compatible with any portafilter. In order to fit any existing portafilter on the market, only that one piece must be modified. The idea is to design multiple brew heads to be used to a portafilter of choice. This opens up even more doors in terms of extraction variables. My design even allows the user to alter the portafilter, and can more effectively imitate a shot pulled on another machine by using the exact same portafilter during the extract.

The lever can be attached a number of ways to achieve the same result. In the sketches, I have the lever set up so that you have to raise it to begin brewing, but it could be attached differently so that you pull the lever down to begin brewing.

If anyone wants to work with me on this project, help is greatly appreciated. I am basically ready to start trying to get this thing produced but having never done anything like this before, I'm not sure how to go about doing this. Right now I'm getting in touch with a number of metal shops to see if anyone is willing to help me and I'm not entirely sure where else to look for help (which is part of why I'm here). Beyond that, if anyone wanted to help get some professional drawings of the design, that could potentially be very helpful. Any suggestions on the design itself are welcome too.

Anyway, I'm going to wrap this up here. Any kind of feedback is greatly appreciated. Thanks for reading.

Hey Jon,

Welcome. Nice ideas going on there. However, there're a few critical problems that you will need to solve. Also, you might want to separate your post to a new topic so you can garner more feedback and not set the current thread off-topic.

i) First, temperature problem. Without a heater in place to saturate the group with heat, all the speculation about temperature control is useless. Even if it is possible to pour in 120 Celsius water, the water will be brewing at sub 80 Celsius instantly. You need to think of a way of heating the entire group. Flushing hot water might work if you flush like 2-3L of water but that's not acceptable and is not controllable.
ii) Mounting - Is that going to be wall mount? You need to produce 9 bar pressure with that and so a sturdy mount is definitely needed.
iii) Material - are you going to use brass, stainless or aluminium? Each has its own problem, and not exactly cheap to machine. I suspect to machine to your design, you might be looking at closer to 1k including the material. If you want to produce it via casting, the initial lay out is extremely high and you don't have much chance to muck with the design - gotta get it right from the beginning.

Last but most importantly, cost issue. I suspect, all up, you will be looking at atleast 2k+ for an espresso-only machine - the more parts/function you introduce, the more expensive it gets. When it gets up to 2k territory, it might be better to get a Strega and modify it to get the triumvirate features you're looking for, and getting an extra function - steaming.

That's why EspressoForge (Andre) is starting this project - using common/standard parts and I think it looks more optimistic with that approach (not saying yours won't work but cost will definitely be an issue). And you will see that a lot of the problem EspressoForge is trying to address are similar to what you'll have to address as well.

p/s: since you're designing an espresso-only open-boiler lever machine, you have to look at the Strietman ES3/CT1.

leverespressoguy wrote:Hi everyone, I am new here.

Hi Jon, welcome to HB.

Looking over your design, I would be interested to see what you come up with for a group head. I hope it can be driven by pressure as well as gravity fed. This thread has evolved to using an existing group and fed by line pressure. But if you create this ultimate group and demonstrate it's capability, I'd be interested in it. Overall, design and discussion I think would warrant a new thread.

leverespressoguy wrote: I've recently become infatuated with espresso machines and I've noticed a bit of a problem in the market for these babies.. In a nutshell, there are no decent, affordable options, for the budding coffee connoisseur and that is a rather large market that could be tapped into. Someone who is just beginning their coffee hobby isn't ready to shell out the $4,500+ required for a machine with temperature control, pressure profiling and pre-infusion. These specific features (or some version of them) are essential in order to be able to extract great shots out of a wide range of coffees and to be able to repeat the exact extraction time and time again. Forget people who are new to the hobby for second, most people in general are never ready to shell out that kind of dough for a coffee machine, which is very sad, since there are a lot of people who are very passionate about this stuff.

It's just the laws of supply and demand combined with material cost, sure the Vesuvius is the one you are thinking of, and to automate pressure profiling it certainly takes a decent amount of tech. Also, keep in mind that your material cost is nowhere close to what you'll have to charge for a commercial level machine. UL listing for a simple electric device starts at around $10k, then you go up exponentially by adding electronics etc.

leverespressoguy wrote: Unless I'm missing something, the cheapest machines that this triumvirate of features can be found on cost around $4,500+ (for the record, I don't consider most existing lever machines to be capable of pressure profiling in any meaningful sense, because the user has no idea what pressure they are generating while using these machines). The reason these machines cost so much, is because the implementation of these features is extremely expensive on all of the machines that have them. Another reason these machines cost much, is because they're packaged with a bunch of things which, at least a few people, have no use for, but have to pay for anyway. My design includes very basic versions of all of these features, however, they are just as functional as the features of a machine like the vesuvias dual boiler and require only slightly more effort from the user, which I believe to be a very reasonable trade-off, considering the price tag on a machine like the vesuvias. My machine also includes the absolute minimum required to produce fantastic espresso.

There are also other levers out there with brew pressure or can be drilled and added, at a much less cost if that is your main issue. I think that while pressure profiling is a neat feature and fun to play with, making it a central design requirement as critical for good espresso just isn't the case. Have you even used a machine that can pressure profile automated or manually?

If you are creating a spring lever group from scratch, do you have an idea of the budget of what you expect the machining to cost? And how much the rest of the machine will cost? Then add in labor to assemble, plenty of other parts to make it look nice...and then if you sell it all, you must support it if anything goes wrong. By the time you do this, you may realize you will need to charge $5-7k for the machine.

I would suggest if you want to go forward, that you focus on the group head only, and make sure you have a market for it. This project was meant to be an outlet for the many spare parts, and existing groups to make into the ultimate functioning lever, so I can see if it works out that some will buy a group, but it will certainly be less numbers than if you could make the entire machine and support it.

leverespressoguy wrote: So enough talk, how about a picture or something? I'm no engineer, so I have no technical drawings or anything like that. I've produced a couple sketches that hopefully illustrate effectively how the design will work, which are below. Please don't be too harsh about my sketches, I have no experience with this kind of stuff.

The god-awful sketches:


A few more notes about my design:

In the sketches there are no dimensions. I figured that the dimensions are going to be based on available materials, so I have created a design that isn't contingent on specific dimensions to work. There is a great deal of flexibility with regard to size of the various components.

Overall I like the sketches, just going on the basics, I can see you've added a pressure gauge as well as a threaded flange at the bottom to presumably change basket sizes and portafilters. What I would like to know, could the same goals be achieved by drilling an existing group and mounting a pressure gauge? 58mm is so common with aftermarket accessories, I have a hard time seeing a reason to go with anything else unless it was just to change out baskets for novelty. Even then, I think smaller baskets could be used with a portafilter adapter kind of part, which would require much less machining and presumably be useful on almost any 58mm machine.

leverespressoguy wrote: If anyone wants to work with me on this project, help is greatly appreciated. I am basically ready to start trying to get this thing produced but having never done anything like this before, I'm not sure how to go about doing this. Right now I'm getting in touch with a number of metal shops to see if anyone is willing to help me and I'm not entirely sure where else to look for help (which is part of why I'm here). Beyond that, if anyone wanted to help get some professional drawings of the design, that could potentially be very helpful. Any suggestions on the design itself are welcome too.

Anyway, I'm going to wrap this up here. Any kind of feedback is greatly appreciated. Thanks for reading.

I'd be happy to help if you need some direction. First I would say that most machine shops wouldn't be able to do the design for you. They may suggest changes based on viability of machining something (thickness changes or threading changes etc).

I would suggest since you don't have precise drawings, that you instead spend some time to learn Google Sketchup or better would be to get an educational version of SolidWorks and learn that. Most machine shops can make anything if you provide them a 3D STEP file. It's also very useful for them to quote you out a price since with just the STP file and the material you want to machined from, they can tell you a cost almost instantly.

samuellaw178 wrote:p/s: since you're designing an espresso-only open-boiler lever machine, you have to look at the Strietman ES3/CT1.

You can also check out this thread:
DIY Open Boiler Manual Lever

It sounds pretty cool but I think it's a bit of re-invention going on. I think that you could modify an existing lever group (Astoria's CMA group is my favorite) and then try one of the DIY guides around this page for dipper designs, etc. I've always been of the opinion that redesigning the "wheel" should start with thoroughly testing all the existing "wheel" designs that already exist. Does a 3 sided wheel work better than a 4? Is there any advantage to a wheel with one flat spot or many? How many flat spots are optimal for wheels? Are there reasons why you may want a flat spot? Are there oval shapes that work for your needs? I probably sound ridiculous but there are many designs for lever machines, some of them could work great for drilling a few extra holes for some temperature and pressure gauges.

First- about the potential cost. Is $2k+ really a realistic figure for this design? I mean we are talking about a few really basic metal parts. Surely each component wouldn't cost more than $100 or so for the metal and the labour?? Estimating $100 for a metal bar, or a cylinder, seems excessive already, so I am shocked to hear cost estimates in the thousands.

There are really only 7 key components (brew cylinder, brew cylinder top, brew head, piston, lever, spring, and water hopper), and each one is pretty basic. Beyond that I'll need some generic parts like a pressure gauge, o-rings, etc... We're talking about a cylinder with a couple holes in it and a few things welded on, a piston head with some grooves for o-rings, a metal bar bent a certain way, etc... There are no electronics, no boilers, there's really nothing complicated going on at all. The parts don't have to have fancy curves or nice finishes, the machine just has to work.

I provided a rough sketch of each component, so perhaps someone citing production costs in the thousands, can explain which components are driving the cost to this level, because looking at the design, I am at a loss here... Perhaps if I have some idea of what exactly is driving cost up, I can figure out a cheaper solution and move forward with that.

Moving on from that potentially project-ruining issue...

A temperature control issue was mentioned. I'm not sure I understand the issue because I don't see any issues with temperature control, other than controlling temperature being a bit inconvenient under certain circumstances.

The design involves a thick metal cylinder with a metal pipe wrapped around it. The idea is to get a kettle with temperature control and a water pump, and pump water of whatever temperature you like through that pipe. The water running through the pipe will heat everything near it to the temperature of the water within a few minutes. Everything the brew water touches will be at the temperature of the water you're pumping through that pipe within a few minutes (perhaps 1 or 2 degrees less because of heat loss, but this can be easily compensated for).

If the user doesn't have access to a kettle with temperature control and a pump, the user can simply fill the cylinder with boiling water for a minute or so, empty it, fill again for a minute or so, empty, then fill with water of desired temperature until ready to brew, empty the water and brew. The thick metal will retain the heat long enough to pull a shot. The whole assembly could be dumped in a hot water bath as well, and the thick metal will retain the heat long enough to pull a shot. The idea behind the design is so that there would be a number of ways to control temperature. Temperature control is a bit crude if you don't have a pump and a kettle with temperature control or some kind of hot water bath with temperature control, but it's still possible to attain a precise temperature of brew water and everything the brew water comes into contact with unless I have grossly misunderstood something about thermodynamics.

As for what the machine would be mounted on, I was thinking of having a counter-top stand. The cylinder would attach to the stand via a clamp, so the entire cylinder can be easily removed and placed in a hot water bath if necessary (or removed for some other reason). There would be a handle on the stand to brace the device while the lever is raised and various other attachments could be clamped on, like a drip tray, etc..

I have seen the streitman machines. In fact, I was inspired by these machines and several others (Pavoni's, Zacconi's, ROK, etc...).

EspressoForge wrote:What I would like to know, could the same goals be achieved by drilling an existing group and mounting a pressure gauge?

Interesting question. I believe the answer is yes, drilling an existing group and mounting a pressure gauge should indicate pressure while brewing... Provided you mount it in the right place anyway lol...

I haven't done much research into modifying an existing group, although the consensus here seems to be that that might be the way to go. So I'll spend some time looking into this approach for now.

I'm very interested in hearing a more detailed cost breakdown of the components required for this design. There have been a few suggestions that this design is going to cost a ton to produce, so I'm wondering why. I have very little experience with this kind of thing, so for all I know, this design may already be too expensive. I can probably spend around $1500 at this point, but I would hope to be able to invest considerably less than that. Anything more than that and I'll just go buy the rocket giotto pp I've had my eye on lol.

Thanks for the responses everyone.

I PMed you already about it, but I was imagining you meant an open boiler integrated into the design. But unless you have the lathe and mill and will be doing this all on your own machines and labor, then yes, you are sorely underestimating how much a machine shop charges for set up fees, especially for prototypes. Now if you already had a perfected design and wanted to make 20-50 units, you can spread that set-up cost over the whole run and make it more economically.

But I also think you may underestimate just how complex a good spring lever group is. It may look simple, but there are a good number of moving parts and places to seal. I also feel you can take more advantage of existing tooling (and the low Euro relative to the dollar) and modify an existing group cheaper.

Take a look here for a guy who drilled out a Pavoni group to install a brew gauge:
Robo-Pavoni; learning to make espresso machine from scratch

leverespressoguy wrote:First- about the potential cost. Is $2k+ really a realistic figure for this design? I mean we are talking about a few really basic metal parts. Surely each component wouldn't cost more than $100 or so for the metal and the labour?? Estimating $100 for a metal bar, or a cylinder, seems excessive already, so I am shocked to hear cost estimates in the thousands.

There are really only 7 key components (brew cylinder, brew cylinder top, brew head, piston, lever, spring, and water hopper), and each one is pretty basic. Beyond that I'll need some generic parts like a pressure gauge, o-rings, etc... We're talking about a cylinder with a couple holes in it and a few things welded on, a piston head with some grooves for o-rings, a metal bar bent a certain way, etc... There are no electronics, no boilers, there's really nothing complicated going on at all. The parts don't have to have fancy curves or nice finishes, the machine just has to work.

I provided a rough sketch of each component, so perhaps someone citing production costs in the thousands, can explain which components are driving the cost to this level, because looking at the design, I am at a loss here... Perhaps if I have some idea of what exactly is driving cost up, I can figure out a cheaper solution and move forward with that.

Moving on from that potentially project-ruining issue...

A temperature control issue was mentioned. I'm not sure I understand the issue because I don't see any issues with temperature control, other than controlling temperature being a bit inconvenient under certain circumstances.

The design involves a thick metal cylinder with a metal pipe wrapped around it. The idea is to get a kettle with temperature control and a water pump, and pump water of whatever temperature you like through that pipe. The water running through the pipe will heat everything near it to the temperature of the water within a few minutes. Everything the brew water touches will be at the temperature of the water you're pumping through that pipe within a few minutes (perhaps 1 or 2 degrees less because of heat loss, but this can be easily compensated for).

If the user doesn't have access to a kettle with temperature control and a pump, the user can simply fill the cylinder with boiling water for a minute or so, empty it, fill again for a minute or so, empty, then fill with water of desired temperature until ready to brew, empty the water and brew. The thick metal will retain the heat long enough to pull a shot. The whole assembly could be dumped in a hot water bath as well, and the thick metal will retain the heat long enough to pull a shot. The idea behind the design is so that there would be a number of ways to control temperature. Temperature control is a bit crude if you don't have a pump and a kettle with temperature control or some kind of hot water bath with temperature control, but it's still possible to attain a precise temperature of brew water and everything the brew water comes into contact with unless I have grossly misunderstood something about thermodynamics.

As for what the machine would be mounted on, I was thinking of having a counter-top stand. The cylinder would attach to the stand via a clamp, so the entire cylinder can be easily removed and placed in a hot water bath if necessary (or removed for some other reason). There would be a handle on the stand to brace the device while the lever is raised and various other attachments could be clamped on, like a drip tray, etc..

I have seen the streitman machines. In fact, I was inspired by these machines and several others (Pavoni's, Zacconi's, ROK, etc...).

Interesting question. I believe the answer is yes, drilling an existing group and mounting a pressure gauge should indicate pressure while brewing... Provided you mount it in the right place anyway lol...

I haven't done much research into modifying an existing group, although the consensus here seems to be that that might be the way to go. So I'll spend some time looking into this approach for now.

I'm very interested in hearing a more detailed cost breakdown of the components required for this design. There have been a few suggestions that this design is going to cost a ton to produce, so I'm wondering why. I have very little experience with this kind of thing, so for all I know, this design may already be too expensive. I can probably spend around $1500 at this point, but I would hope to be able to invest considerably less than that. Anything more than that and I'll just go buy the rocket giotto pp I've had my eye on lol.

Thanks for the responses everyone.

For low volume production, yes. If you can scale it up efficiently, the price can be brought down as EspressoForge has done with his EspressoForge. But still it will still be on the high side. You probably already know this, you have to start with a larger bar stock because the machine also needs an end to hold onto, and trim of the excess etc. ie. if you're making 2''x2'' piston, you have to have stock bigger than that, and yeah, there's the set up cost. If you plan to chrome it (for lead concern if using brass), that's additional cost and easily another couple hundreds of dollar.

It's a long process to source those parts individually, not to mention all the back and forth communication/coordination required for all the parts. If you're planning to make it worthwhile and to sell for small profit, it won't be cheap.

These are cost breakdown of what I imagine to be, not including the heater (which I think is essential to the design) and your labor is free.

Cylinder = 200, top cap 100, lever=150, bottom part = 100, piston rod = 50, portafilter 80, hopper = 50, spring = 20, gauge=20, gaskets misc = 50 Mounting/frame = 100 drip tray = 50. That'd be close to 1k. Also, when starting a new venture, something will always go wrong and you have to plan for that.

What kind of pump/valve/lever bearing mechanism do you plan to incorporate? All these extras incur additional cost. Also,you'd have to make sure the group design has the ability to handle the torque/pressure in the long run - something that you'll only find out after having a prototype.

If a functioning group head can be easily machined cheaply, I'd imagine the many machinists among HB crowd would have done so.

Re temperature control, I am not sure what are the exact details you had in your machine. But from my first hand experience, trying to warm up a chunk of metal and maintain it there is not easy - so on subsequent shots you have to keep preheating the machine and it's hard to nail on the same temperature. Without the pipe/heat exchanger system, I imagine to make one espresso, you need to boil about 2-3L of water and flush them through the system. Otherwise, the metal will absorb and disperse the heat immediately the moment you stop flushing. With the pipe/heat exchanger system, you have to ensure an efficient heat transfer onto the cylinder - maybe press flat against it? The differential is definitely more than a couple of degree so some experiments need to be done there.

Have you seen a Rossa PG btw? I recommend to look into that as well. If you don't mind inconvenience, that gives a great control and satisfies your requirement easily - and cheaper. Pressure profile and preinfusion are in total control with a large 2.5inch Omega gauge. Only thing the temperature profile is fixed and you have to pull your shot quickly to avoid excessive heat losss (you can preheat to 93-95C but it will inevitably drop from there).

From what I've read, it really does seem like the goals here could be accomplished by mounting a pressure gauge right into the group of an existing lever machine. Actually the EspressoForge might be the perfect solution to the OP's stated problem of a pressure profiling cost effective machine.

I would also disagree with the OP that spring levers can't do true pressure profiling, I know my machine and spring very well and have no problem repeating profiles. I should also add that building your own portafilter pressure gauge as a diagnostic and to learn how your spring functions is rather inexpensive.

That said the idea to mount a pressure gauge into one of my groups is intriguing...

The espressoforge looks really interesting... Also I don't mean to offend with my spring lever comment... All I'm trying to say is that no pressure gauge is not ideal.

I agree that a group pressure gauge would be a big plus. I also like the idea of being able to hot swap the springs. If you could swing it so it doesn't require turning off the machine or 10 minutes of labor that would be a pretty novel feature.