Cheers Andy, I wouldn't say it's down to design, I'm a firm believer the grind quality / type is solely dependant on the type of burrs used, it's cut and size. I'd expect the same results from vertically / horizontally mounted burrs, with / without exit chute, retention-less or not, as long as it was the same burrset.

I've only started playing with filter coffee using grinds from the ZR-71 recently. I've seen many raving reviews from people using conical hand grinders used for brewed coffee and I was a bit surprised, I always assumed that bi-modal isn't so great for filter / brewed, as it leads to uneven extractions. It all started with some quality SQM ground coffee, left over from a test session, I wasn't going to throw that away, so I brewed me a cup. This was a super fine grind and yet the coffee came out very clean, with no hints of over extraction. Today I brewed more, purposely ground this time on a coarser setting, same thing, delicious brews. I will experiment with it more and see if the trend continues, maybe it's all placebo, or maybe my Guatemala is very bad in comparison? I've had the big Mahl for some time and had mixed results from it, so far the ZR-71 blows it away on all levels, so make a guess yourself on what's broken and what's not.

It is possible to fit a flat burr set on the ZR-71, I haven't got the parts yet as it's not on the priority list at the moment. I haven't really experimented with flat burrs at all to be honest, so I'm not sure how it compares to a conical burrset in terms of design requirements, but fitting a 98mm Mahl burrset sure does sound tempting:)

Regards,
T.

Any update to share?

Not much, I've had the machine running for a while, trying to organise a get-together with a few people and pull some shots on an L1, also compare to a few bigger conicals.

Regards,
T.

What a nice project. Are you planning on taking this commercial at some point?

Probably not, it would be too much for me both time-wise and financial-wise.

Regards,
dsc.

Well that sure is an excellent hobby project

Hobby indeed, still enough to chew through ones wallet though

Regards,
dsc.

2mm gap macro shot:

https://www.flickr.com/photos/tompjagiello/13653300145/

Regards,
dsc.

Front shot showing the burr gap, pretty easy to clean:)

https://www.flickr.com/photos/tompjagiello/14019293752/

Regards,
dsc.

Very nice project going here! Just curious, if you don't plan on marketing and producing the grinder, what's the point of all the secrecy? You are going to reveal it eventually, right? So what's the difference?