# Calling all conic users...



## dsc (Jun 7, 2013)

I wanted to run a grinding experiment and I'm looking for people with conical grinders, ideally single dosing ones. It also wouldn't hurt if you have a refractometer









If interested, reply below!

T.


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## igm45 (Mar 5, 2017)

dsc said:


> I wanted to run a grinding experiment and I'm looking for people with conical grinders, ideally single dosing ones. It also wouldn't hurt if you have a refractometer
> 
> 
> 
> ...


I've got a hg1

No refractometer though....


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## dsc (Jun 7, 2013)

Hmm should work









No other conic lovers here? What about all the Kafatek peeps, surely there must be some conics there?

T.


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## Stanic (Dec 12, 2015)

I can help too I guess, no refractometer available


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## Rhys (Dec 21, 2014)

Wait a month or so, and the forum will be flooded with Niche owners


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## Nod (Sep 7, 2013)

Does a M3 count? I have a refract


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## Aidy (Jul 8, 2015)

igm45 said:


> I've got a hg1
> 
> No refractometer though....


Me too.


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## dsc (Jun 7, 2013)

The idea behind this experiment is fairly simple, although time consuming so not sure how many will want to try this. I was playing around with slow bean feeding on the ZR and it turns out you can grind much finer when dropping in beans a bean at a time. For example a normal setting for a 17g double would be 0.70mm burr gap if I drop the whole 17g of beans in one go, or 0.55mm if I drop the beans very slowly, a single bean at a time. This is a massive change in grind setting and seems to produce very tasty shots, slightly different from normal grinding (too early to tell for sure though and I've not tested this with other people).

So, if you can spare two minutes, give it a go and report back







all you need is to turn the grinder on, leave it running and drop beans in the hopper / burr chamber. Afterwards make sure to mix it all well, although theoretically it's not so important as you won't have the effect of the grinds getting coarser as the beans in the burr chamber run out.

The above might work on flats as well, but I've not tried it myself.

T.


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## Stanic (Dec 12, 2015)

As I'm now sorting out issues with cracked cover glass on the pressure gauge on my Rossa, I won't be able to help ATM, but you've got me curious about the results with the Kinu M68


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## MildredM (Feb 13, 2017)

I can give this a go, it sounds really interesting. No r/meter mind you.


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## Rob1 (Apr 9, 2015)

Could try it with the Pharos I guess. Might be of help with lighter roasts which I don't have at the moment but just got a bag of mystery 8.


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## DavecUK (Aug 6, 2013)

I could do a test on Niche, one grinding an 18g dose and the other grinding 1bean at a time, keeping it on same grind setting. Then see if shots pour same amount, time, taste etc. Should validate whether grind shows marked difference at 330 rpm speeds.


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## dsc (Jun 7, 2013)

From what I've seen, without changing your setting, a bean by bean grind should produce a proper gusher.

T.


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## MWJB (Feb 28, 2012)

dsc said:


> From what I've seen, without changing your setting, a bean by bean grind should produce a proper gusher.
> 
> T.


So feeding bean by bean makes the grind coarser at the same setting?


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## dsc (Jun 7, 2013)

That or the particle shape changes, or you simply get less fines as there's less back force. No idea which of these happens as there isn't a good method of analysing coffee particles :/

T.


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## MWJB (Feb 28, 2012)

dsc said:


> That or the particle shape changes, or you simply get less fines as there's less back force. No idea which of these happens as there isn't a good method of analysing coffee particles :/
> 
> T.


Well, if you get less fines (less particles under a certain size) there must be proportionally more larger particles & therefore a coarser grind?

NS did some shape analysis but other than that I'm not sure there's any relevant shape data? Break the beans in the dose into an average half a million pieces & they're going to be all sorts of shape surely? Difficult to conclude that this % of cubes vs. that % of starfish vs. a % of unicorns is significant vs differing proportions, or throwing some top hats in the mix?


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## dsc (Jun 7, 2013)

Guess it depends how you define coarseness, if coarse is fast flows and fine is slow flows per dose then yes







I'm afraid it's not that straighforward with grinders as you get varied particle sizes / shapes in a full dose, at least that's the way I look at it. With a normal dump method you get more fines at the start and less (or more coarse particles) at the end, with a bean-by-bean dosing you should get similar sized particles throughout (with some variance of course).

The whole reason why I started playing with this is because I've seen a note on a roller grinder manufacturer's website which mentioned that rushing beans through the rollers is bad as it causes more breakage from bean contact and thus changes the particle distribution compared to a slow flow through the rollers when the beans have more space to "breath". I reckon other types of burrs might respond in a similar fashion assuming they are force fed.

As for shapes one way would be to perhaps run samples through a microscope? but as you've said, there's bound to be loads of different shapes anyway so comparison would be rather hard / impossible. This is also one of the reasons why I'm suggesting for people to try it and see for themselves. One theory behind all of this is that you're grinding finer, thus "opening" the coffee beans more and perhaps extracting more, so it must be better?

T.


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## MWJB (Feb 28, 2012)

The theory could work out that way if there were less fines made in the single feed method (less choking limiting extraction), but also fewer larger particles too (less large particles pulling the EY down), so all in all a narrower distribution than dump. But in the dump method, don't you get the coarser particles at the end because there are fewer beans in the throat of the grinder (like in the single feed scenario)?

Maybe just sifting the coarsest 10% would tell you if there's a difference at that end?


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## matharon (Dec 22, 2014)

I usually grind 36g through an E92 with a feed tube and puffer with almost zero retention and then split the grind into two 18g double shots.

Just occasionally when grinding 18g for only one coffee I have noticed it gives 36g through same bottomless p/f a few seconds quicker than usual with same tamp pressure.

Maybe your theory is the reason.

At one time I did try to change setting but now don't bother.


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## DavecUK (Aug 6, 2013)

dsc said:


> From what I've seen, without changing your setting, a bean by bean grind should produce a proper gusher.
> 
> T.


I have done my test. One of the problems of course is that the Niche stops and starts each time I raise or lower the lid...but always the last bean or 2 popcorns so I did 2/3 beans at a time, which equates to being dropped 1 by 1 in another grinder. I make the assumption that the grinder never getting up to speed and starting stopping probably had little effect on grind quality (because of grinders like the HG1). I can confirm the following for 18.03 g of coffee ground at the same grind setting.

1 by 1 beans = Visibly coarser grind. grind particles must also be different shape as packing and packing pressure was different, grind sat slightly higher than normal in the portafilter basket. The shot was much faster (gusher)

18.03 g of coffee all at once = Usual grind packs better fluffier, occupies slightly less volume in basket...normal pour as expected.

*
This would seem to confirm your own tests. I would add that I am certain not only the particle size but the shape produced is different. This also tells us that the grind quality of any single dosing grinder e.g. HG1, Kaffatek Conical, Niche etc.. must change progressively as the dose is ground through. It would necessarily follow that mixing the ground coffee from these grinders would be a requirement.*

I have noticed with the Niche that using the grind cup placing portafilter on top and inverting seems to give better pours....a reasonable explanation would be the bottom to top mixing that occurs as a result.

Hope it's been of some use to people.


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## igm45 (Mar 5, 2017)

Just to 2nd @DavecUK view...

I single dose into a tupperware pot, shake, then empty into LW tumber before it reaches the pf.

I have found less prep results in less in the cup. This experiment goes some way to explaining why thats the case!

So...thanks


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## dsc (Jun 7, 2013)

MWJB said:


> The theory could work out that way if there were less fines made in the single feed method (less choking limiting extraction), but also fewer larger particles too (less large particles pulling the EY down), so all in all a narrower distribution than dump. But in the dump method, don't you get the coarser particles at the end because there are fewer beans in the throat of the grinder (like in the single feed scenario)?
> 
> Maybe just sifting the coarsest 10% would tell you if there's a difference at that end?


At the end of a dump grind you should get the same coarseness as if dropping single beans in. I think the beginning of a dump grind produces the finest particles as there additional bean vs bean rubbing and bean vs burr rubbing happening along the entire burr. As you move through the dose dumped the grind gets coarser until at the end you are grinding single beans giving you the largest (or of a different shape) particles. This is one of the reason why you can't single dose directly into a basket and tamp, the ground dose simply isn't mixed but layered instead.

T.


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## dsc (Jun 7, 2013)

DavecUK said:


> I have done my test. One of the problems of course is that the Niche stops and starts each time I raise or lower the lid...but always the last bean or 2 popcorns so I did 2/3 beans at a time, which equates to being dropped 1 by 1 in another grinder. I make the assumption that the grinder never getting up to speed and starting stopping probably had little effect on grind quality (because of grinders like the HG1). I can confirm the following for 18.03 g of coffee ground at the same grind setting.
> 
> 1 by 1 beans = Visibly coarser grind. grind particles must also be different shape as packing and packing pressure was different, grind sat slightly higher than normal in the portafilter basket. The shot was much faster (gusher)
> 
> ...


Thanks for doing this so quickly, the next step would be to adjust for the coarser output and aim for a normal shot with bean by bean dosing. I had to drop the burr gap by around 0.10mm - 0.15mm to get something usable, so if your grinder is using 1mm pitch on the threaded adjustment collar,/knob you'd need to turn the collar/knob into finer territory by 36 - 54deg (a rather hefty adjustment).

Of course there's no saying that this "new" grind is better, but if one can experiment, I'd encourage it

I'm currently trying to come up with a simple mechanism to help bean feeding but it seems like a rather complicated thing to design, mostly because of the nature of coffee beans.

As for having to mix grinds coming out of single dump doses, see above and if you are currently doing this go and get yourself a mini whisk for whisking grinds

T.


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## dsc (Jun 7, 2013)

Anyone else had a chance to try this?

T.


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## DavecUK (Aug 6, 2013)

dsc said:


> Anyone else had a chance to try this?
> 
> T.


I came back to this thread to check out the results from other forum members with conical grinders.....?


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## Snakehips (Jun 2, 2015)

I finally got around to trying this on the Kafatek Monolith Conical.

Found an unopened bag of Rave Colombia Suarez Project roasted end of March lurking at the back of a cupboard that would otherwise be given away so used them for the comparison.

Not intending to be dialling in for taste , I made a nominal grind setting.

Test doses weighed in at between 18.00g : 18.06g and out at between 17.93, : 18:03g

Direct into portafilter.

No stirring, just a shake to level.

Tamped on PuqPress @ 10kg, so should be consistent and level.

Depth of tamped dose below top of basket measured with vernier.









Dose 1 : Full dose Depth of tamp 12.1mm

6 seconds PI 18 > 36g in 25 sec

Dose 2 : Bean by bean Noticeably coarser Depth of tamp 8.89mm (3mm diff !!)

An absolute gusher. Would not resist 3.5 bar PI

Dose 3 : Full dose Depth of tamp 12.2mm

6 seconds PI 18 > 36g in 24 sec

So pretty much identical to Dose 1

Steamed some milk and had a more than acceptable flat white.









Dose 4 : Bean by bean having adjusted grind 18º finer. Depth of tamp still only 10.3mm so only one third the way finer, based on the difference in depth.

Did not bother to pull shot as it would likely have been another gusher.

@dsc If you should go on to conclude that there is a discernible taste benefit derived from the consistent particle size of bean by bean dosing........ then please keep it to yourself!

Bean by bean is a PITA too far !!!


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## dsc (Jun 7, 2013)

Thanks for trying this out @Snakehips !

If someone could try to dial in for taste using bean to bean that would be awesome. If you can't figure out the ballpark setting, let me know which grinder you are using and I can help out (assuming I can find the pitch size for the adjustment thread).

Also, I'd suggest always mixing your grinds post grind when single dosing, otherwise you'll end up with those coarse "bean-by-bean like" particles on top of your puck (as beans get ground there less of them in the burr chamber and they start to resemble a bean-by-bean scenario thus producing coarser particles). With single dosing your grind profile (if you want to call it that) is increasingly coarser, finest at the start and gradually getting coarser. Hopper fed grinders will be more steady, which is one of the reasons why they allow you to grind coarser overall when compared to single dosing (with the same bean of course).

T.


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## jj-x-ray (Dec 31, 2017)

Interesting effect. Would it be the same particle size ie the only difference between bxb and normal single dosing is the grind setting? Is there a way to exploit the effect? Also by logical extension does that mean full hopper dosing has the finest particle size for the same grind setting?

I can see threads about vacuum sealing individual beans.....arghhh


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## MildredM (Feb 13, 2017)

Totally forgot to try this, sorry! I will have a go today


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## dsc (Jun 7, 2013)

MildredM said:


> Totally forgot to try this, sorry! I will have a go today


Aaaaand?









T.


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## dsc (Jun 7, 2013)

jj-x-ray said:


> Interesting effect. Would it be the same particle size ie the only difference between bxb and normal single dosing is the grind setting? Is there a way to exploit the effect? Also by logical extension does that mean full hopper dosing has the finest particle size for the same grind setting?
> 
> I can see threads about vacuum sealing individual beans.....arghhh


I'm not so sure the particle distribution would be the same as single dosing is a gradually coarser profile, whilst bxb is constant (I think). Yup hopper fed / force fed grinding will generate the finest grind for a given setting, with single dosing producing a coarser overall grind and bxb being the coarsest.

I've had some really tasty shots with bxb and I keep using it although agree it is a pain in the bottom (trying to come up with a simple mechanism to automate this). Not done back to back tests vs properly dialed single dosed shots, so can't comment. It is interesting how much finer one has to grind with bxb to get a normal flowing shot.

T.


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## MWJB (Feb 28, 2012)

dsc said:


> I've had some really tasty shots with bxb and I keep using it although agree it is a pain in the bottom (trying to come up with a simple mechanism to automate this).
> 
> T.


Some kind of auger maybe?


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## dsc (Jun 7, 2013)

MWJB said:


> Some kind of auger maybe?


Tried that, went with a feed screw arrangement, but coffee is really hard to transfer this way as beans keep getting stuck between the screw and the walls. I'm sure if the motor to drive the screw was beefy enough it would just sheer the beans, but I'm trying to keep this as small as possible







I'm most likely overthinking it, or looking at it from the wrong angle, so need to let the ideas stew for a wee bit longer









T.


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## DavecUK (Aug 6, 2013)

dsc said:


> I'm not so sure the particle distribution would be the same as single dosing is a gradually coarser profile, whilst bxb is constant (I think). Yup hopper fed / force fed grinding will generate the finest grind for a given setting, with single dosing producing a coarser overall grind and bxb being the coarsest.
> 
> I've had some really tasty shots with bxb and I keep using it although agree it is a pain in the bottom (trying to come up with a simple mechanism to automate this). Not done back to back tests vs properly dialed single dosed shots, so can't comment. It is interesting how much finer one has to grind with bxb to get a normal flowing shot.
> 
> T.


The probability that more beans at once vs BxB are swings and roundabouts with BxB the longer way to achieve a similar/same grind fineness. The only difference being perhaps a tighter particle size distribution with the latter....which may or may not be better for extraction?


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