As best I can tell (limited experience, but plenty of research), such a thing unfortunately does not exist.
There is a huge body of discussion on this site on pros/cons of all types and styles of grinder, most would agree that any purchase will result in some compromise?
So, as long-term project, I am considering building a grinder which will meet more of my future needs:
1) High grind quality
2) Very fine grind adjustment (easy to use & repeatable)
3) Very low grind retention (doserless)
4) Durable design and construction
5) Compact size
I foresee something along the lines of the Versalab, but less radical, more durable, and utilising more standard parts.
To my question; what would those in the know suggest as the ideal burr set to base the design around? So far I have considered Mazzer Kony, Mazzer Robur & Compak K10.
Should I be considering large flat burrs, or something different completely? Any feedback will be most appreciated.
Theres a DIY Grinder thread on Home-Barista. Some ideas there (and pics of a set of conicals getting rigged).
My preference is for conical also, as all my research suggests that big conicals are the ultimate.
Due to the different size/speed/quality options available, I was hoping there might be some consensus on which conical is best (within reason of course, it would be hard to justify anything bigger than 71mm?).
Conicals seem to provide the best grinding experience for espresso. Is this an espresso-only grinder though? If its a pourover grinder, Id be going flat!
Not sure that #3 is an accurate summation of the need, isnt the need in fact "short, clean grind path?"
Perhaps consider the grammage of freshly ground coffee it takes to purge stale grounds from the grind path, the dosing area and the drop, eg. "The only problem with the BNZ is its cavernous maw".
I reckon (now this is only a theory with no practical experimentation) that if you were able to get positive pressure through the grind chamber along with a short smooth grinds path (chute) you would have almost no grind retention. Getting the pressure is the major problem - Youd need some sort of automatic bellows. *:-/
Thanks for the info so far, the DIY grinder project at HB is interesting.
I would plan for a dedicated espresso grinder, but I think it would be possible to design an adjustment mechanism for relatively quick transition from fine to coarse for plunger etc. (not sure about pour over). This is to be proven though...
Short, clean grind path is an accurate assessment of what I would be after.
The first stage is drive selection and burr carrier/adjustment assembly, but before that I need to settle on some burrs :-/
If it is a dedicated espresso grinder then I would look at the mazzer Robur burr set (71mm conical) - simply because they are an readily and widely available set of burrs that are known to be of high quality. However If you are looking at a multi-use grinder then conicals or any flat burr espresso oriented burr set is not the answer.
For brewing espresso a repeatable and particular amount of fines (small dust like particles) are desirable to help glue the puck together. On the other hand for any other form of brewing you really want to have a consistent particle size.
I think that Robur burrs are the way to go also, has anyone out there held on to an old/blunt set they would be willing to part with? If so, please send me a PM as I need to get some measurements.
Looking to grind adjustment, I was anticipating a range of 0-1mm (between burr cutting faces), can anyone back this up, or suggest a different range?
To cover a 1mm distance I plan ~108 turns of a handwheel (attached to a worm shaft). A counter would be coupled to the shaft to give a round number indication of where you are in the scale. The handwheel would have its own scale, broken up into 50 increments.
So in theory 1 full turn = 0.01mm, one handwheel increment = 0.0002mm in terms of relative distance between burrs. I estimate 108 turns to traverse the full scale would take ~30-40 seconds.
Am I way out, or have I missed anything?
I am still tossing around overall layouts, the hardest part of the whole design looks to be point 3, a short & clean grind path. I do like the Versalab here, but am not keen on the drive shaft being "cantilevered" from the top. Has anyone seen any machines that do well in this area, which I should consider "borrowing" ideas from?
I am without credentials completely on this topic but unburdened by knowledge my lay/consumer view is:Originally Posted by 696E6F7979731A0 link=1258001353/8#8 date=1258378200
- The traditional grinder arrangement with the grinder adjustment thread and grinders in the same plane seams ideal, as woof or wobble will be minimised (Ill hope this is understandable and the terminology forgivable).
- The use of a conical coarse grinder and specifically designed fine grinder discs may allow the fine grinder disc to be designed with minimum compromise to function required (precision fine grinding).
The Versalab has gravity and grind path in its favour, the belt drive allows compactness, I wonder about woof or wobble as bearings age.
Why not mount a traditional style grinder at an angle off vertical (X) so the grinds delivery path could take partial advantage of gravity (90-X degree vector).
- to overcome hopper problem created by the off vertical angle, use a plain cylindrical tube as a hopper with a spring loaded piston to load the beans and apply a suitable pressure independent of hopper bean mass (which would contain only a double off beans or two).
The cylindrical hopper tube could contain a breech bean loading port or vertical hopper.
or The piston face could incorporate a valve to allow loading through the piston without its removal from the cylinder/hopper tube.
Food for thought or CRAD!
(Complete Rubbish and Disregard)
how long would it take to unscrew the burrs based on your current adjustment rate? perhaps an electronic rather than manual readout with 0 actually being where the burrs touch would give an interesting repeatability.
could you fling in hopper-based scales to allow an approximation of total kg throughput?
All good food for thought, thanks Lindsay. I will look into slanting the whole arrangement and see if it can work & I was planning a small simple hopper, so the cylinder idea has potential.
I would want for the worm adjustment mechanism to be easily de-coupled to facilitate removal of the burrs fairly quickly, you are correct CF that using the handwheel would take a long time!
My background is mechanical, so I planned to keep the electronics to a minimum ;) Im not sure throughput is important for domestic applications (primary use), but weighing a dose in the hopper before dropping would be nice??