# Particle distribution size of various grinders



## risky (May 11, 2015)

The results of Socratic's testing are starting to come through. Interesting 'curve' on the HG One.


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http://instagr.am/p/-1QCfxyuHk/


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## GCGlasgow (Jul 27, 2014)

I don't understand that?


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## hotmetal (Oct 31, 2013)

AFAIK tall and thin means consistent even grinds (out of 100g ground, about 50g fell within the range indicated on the x axis) so the Ditting gives a tight particle distribution with 50% of particles at the selected size, whereas the HG1 (which they suggest was not run in yet) was giving a wide variation in particle size from fines to granules.

What that tastes like in practice is another matter of course.


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## MWJB (Feb 28, 2012)

All the curves are interesting, Socratic say that their sieving doesn't over-emphasise fines, but despite 20 mins of shaking, nothing at all seems to be landing in the pan, nor the bottom sieve?

But, taken as comparative tests, granted they are interesting & also reflect the wider Robur vs EK distribution that Hemro's particle analysis showed.


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## NickdeBug (Jan 18, 2015)

So their method is stacked shaker seives?

Not surprised that fines don't get through. If done dry then the electrostatics will not help.

In the New Year I will be on a mission to test as many grinders as possible on a Malvern 3000. Been planning for a while but needed to get the help of a mate with the equipment. I now have access to it myself so will run this as a little project.

I will start a thread in Jan inviting anyone who wants to to submit a sample from their grinder for analysis. I will have to get hold of a few kg of the same beans so that the grinder is the only variable.

Of course, particle size is only part of the story. It's how they taste that really matters, but it woukd be nice to see if there is any statistically sound relationship between particle size and taste quality.


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## Jon (Dec 3, 2010)

NickdeBug said:


> I will have to get hold of a few kg of the same beans so that the grinder is the only variable.


This sounds like an interesting experiment but there would still be many other variables at play including humidity, temperature... Erm and some others. Maybe.


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## risky (May 11, 2015)

Yeah I don't know how you would be able to tightly control the experiment.

In this Socratic one for example the sample grind was obtained by dialling in each grinder until they got a 20>40>25 shot. If people were sending you samples I think the difference in equipment would be too variable to be able to say that it was a fair comparison?

This is another interesting slide, showing how soluble particles from the same sieve were, depending on which grinder had ground them:


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http://instagr.am/p/-y8zpwSuMO/


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## MWJB (Feb 28, 2012)

risky said:


> Yeah I don't know how you would be able to tightly control the experiment.


Well, the experiment is to see what the grinders produce in real world situations...either to achieve a given EY, best flavour, or to meet a brew ratio vs time combo (all accepted methods of dialling in). it might be a bit of a stretch to assume that every bean will grind up the same & exactly match the chart, but if they are taking the curves from multiple samples per grinder, trends will show (for their, unique method of evaluation).

Of course, a 2:1 EK shot might not be considered typical, nor the Ditting result.


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## Dylan (Dec 5, 2011)

risky said:


> Yeah I don't know how you would be able to tightly control the experiment.
> 
> In this Socratic one for example the sample grind was obtained by dialling in each grinder until they got a 20>40>25 shot. If people were sending you samples I think the difference in equipment would be too variable to be able to say that it was a fair comparison?
> 
> ...


You could take multiple samples from a grind off event, knowing these were about as accurate as you could hope for. Then anyone who wants to send a sample would come with the caveat that it could be affected by other factors and shouldn't be taken as exactly correct.


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## Dylan (Dec 5, 2011)

Just looking at that graph...

I know the EK has a lower peak than the Ditting, but should this thin high peak of the Ditting produce some of the lauded qualities of the EK, i.e. clear distinct shots. Which ditting was it and has anyone here used it?

Edit: the following posts with how the distribution changes with seasoned burrs is really interesting, double peaks flatten out into one hump.... a more even distribution. Fits with the common thinking.

It also sheds some light on why people have trouble with their HG-One grinders when they first get them, on that graph it has multiple peaks, if these flatten out with use then it would be a clear indication of it improving. Would really hope that manufacturers would find a way to pre-season before selling, especially with a high end hand grinder which takes so much work to season.


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## 4085 (Nov 23, 2012)

I have two Mythos and the burrs will be of different ages. Would you expect the same result?


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## MWJB (Feb 28, 2012)

Dylan said:


> You could take multiple samples from a grind off event, knowing these were about as accurate as you could hope for. Then anyone who wants to send a sample would come with the caveat that it could be affected by other factors and shouldn't be taken as exactly correct.


But still, what would be the constant? It doesn't matter so much where everyone is, more what typical, useable grind distributions from a given grinder look like. Multiple samples from the same model of grinder would be good (e.g. from different homes).


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## MWJB (Feb 28, 2012)

dfk41 said:


> I have two Mythos and the burrs will be of different ages. Would you expect the same result?


Similar results over multiple tests of each, for a controlled condition, assuming one set isn't brand new out of the box & the other blunt.


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## Dylan (Dec 5, 2011)

Just added a couple of edits to my previous post.

All these questions are interesting, mutiple samples from the same grinder around the country, all with similar age of burrs, so environmental impact can be tested, would be interesting. To answer everything is a lot of testing however.

Do we assume the author of this Instagram is having samples sent in, so may be affected by the same potential problems?

Edit: The ditting was a coarser grind, as it isn't made for espresso.


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## risky (May 11, 2015)

MWJB said:


> Of course, a 2:1 EK shot might not be considered typical, nor the Ditting result.


Yes that's the point @robashton was trying to make in the comments on Instagram.

And worth pointing out to anyone going "wow I'm buying the ditting" that the shot couldn't be slowed past 25s.


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## MWJB (Feb 28, 2012)

Dylan said:


> Edit: The ditting was a coarser grind, as it isn't made for espresso.


The Ditting has the narrowest distribution, not the coarsest grind. The grinder has to deal with grinds from Turkish (100um) to 900um so it's probably the adjustment mechanism that plays a bigger role in espresso capability. The new Peak burrs look like they have something in common with the Ditting 804 burrs.


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## DavecUK (Aug 6, 2013)

I had a look at the chart...but I don't really understand what this all means?


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## garydyke1 (Mar 9, 2011)

Be interesting to see the results of the distribution when dialled in to be a specific EY rather than recipe


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## Dylan (Dec 5, 2011)

MWJB said:


> The Ditting has the narrowest distribution, not the coarsest grind. The grinder has to deal with grinds from Turkish (100um) to 900um so it's probably the adjustment mechanism that plays a bigger role in espresso capability. The new Peak burrs look like they have something in common with the Ditting 804 burrs.


There is an asterix on the first graph which says the ditting could not reach the required fineness for the 40g/33s shot, so it was in fact coarser.


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## MWJB (Feb 28, 2012)

% of the ground weight down the Left hand side.

Particle size along the bottom.

So Ditting had 53% (53 gof the 100g sieved) of the coffee land in the 0.3mm size range, but nothing over 0.5mm. This is a narrow distribution with a high proportion of grinds in a tight range.

The Robur had about 35% in the 0.3mm range, 10% at 0.6mm, and grinds up to ~0.9mm. A wider distribution.

The theory is the tighter the distribution the more you can extract from the coffee (but will normally mean longer shots). A higher peak should mean better clarity. A wider distribution means a bigger range of over & under-extracted particles in the mix.


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## MWJB (Feb 28, 2012)

Dylan said:


> There is an asterix on the first graph which says the ditting could not reach the required fineness for the 40g/33s shot, so it was in fact coarser.


No, the Ditting could not reach the required *resistance* to slow the shot to 33s...all the other grinder could because they had more larger particles (a higher median particle size = coarser). Fineness does not = a slower shot, it's the mix of particle sizes.


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## Dylan (Dec 5, 2011)

Right... but they are testing all the grinders at the same resistance, had they been able to make the ditting finer, and thus increase the resistance, they would have. You may disagree, but to me this is not reacing the desired fineness.

And of course fineness equals a slower shot, particle sizes play a part but saying fineness doesnt equal a slower shot is flat our wrong. It clearly does.


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## MWJB (Feb 28, 2012)

Dylan said:


> Right... but they are testing all the grinders at the same resistance, had they been able to make the ditting finer, and thus increase the resistance, they would have. You may disagree, but to me this is not reacing the desired fineness.
> 
> And of course fineness equals a slower shot, particle sizes play a part but saying fineness doesnt equal a slower shot is flat our wrong. It clearly does.


The Ditting did not meet the target resistance, therefore was not tested at the same resistance.

The Ditting has the finest grind of all the grinders tested, based on median particle size (mode seems similar for some but that could be down to sieve selection, there's no data on mean particle size - all affect "coarseness/fineness"). All the other grinders, all of which offered more resistance, had coarser grinds in this respect.

For a given grinder, going finer with that grinder's distribution makes for more resistance (this test is of different grinders, but you can also reach a point where you go fine & shots speed up due to channelling/puck fractures). But another grinder, with a finer grind & less large particles can have less resistance. The EK43 is an example of this, it typically grinds finer overall than other grinders, but the shot is faster &/or longer than grinders with a wider distribution.

A wide range of particles (inherently coarser, even at the same mode) makes it easier to slow the flow via resistance.


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## Dylan (Dec 5, 2011)

Yea, I understand that. I just think saying fineness does not equal a slower shot is a gross over-simplification, I can absolutely see what you mean in that the fineness of the ditting is greater than other but does not create the resistance. However given the same grinder fineness is exactly what creates a slower shot.

You are right to pull up my first post saying 'the ditting was coarser' as you say above, this is not the case. It was too coarse to create the required resistance given the grinders characteristics, but not coarser in comparison to the other grinders.


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## risky (May 11, 2015)

Someone on the Instagram comments pointed out that tightest range should translate into greatest repeatability shot to shot.


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## risky (May 11, 2015)

dfk41 said:


> I have two Mythos and the burrs will be of different ages. Would you expect the same result?


They are going to test that. All the grinders will be analysed with new burrs, seasoned burrs (12kgs+ through them) and burrs that are past the manufacturers recommended life I.e dull.

Here's the one for the Mazzer Major:


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http://instagr.am/p/-1SmbuSuMc/

For now you can look at this comparison they did of the Mythos with the clima pro on and off. And the difference (albeit very minor) that it makes.


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http://instagr.am/p/-wK1YlyuG7/


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## Dylan (Dec 5, 2011)

risky said:


> For now you can look at this comparison they did of the Mythos with the clima pro on and off. And the difference (albeit very minor) that it makes.
> 
> 
> __
> http://instagr.am/p/-wK1YlyuG7/


I wasn't sure of the point in this test, maybe an extra line showing the distribution after a busy service with the Clima Pro tech off... but even then the Clima Pro tech is just there to maintain a happy medium is it not?


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## risky (May 11, 2015)

MWJB said:


> The theory is the tighter the distribution the more you can extract from the coffee (but will normally mean longer shots). A higher peak should mean better clarity. A wider distribution means a bigger range of over & under-extracted particles in the mix.


Am I right in thinking this graph supports that:


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http://instagr.am/p/-y8zpwSuMO/

Showing the ditting, with the narrowest distribution achieved significantly higher extraction. Although this graph shows extractions on similarly sized particles, so analysing the dittings 177-250 micron grind vs. The other grinders particles of the same size. This would indicate the way in which the ditting grinds the particles makes them more soluble?

Obviously the shot time was also very short in comparison so is this maybe another curveball grinder which Can work very well for espresso but requires a different technique?


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## risky (May 11, 2015)

Dylan said:


> I wasn't sure of the point in this test, maybe an extra line showing the distribution after a busy service with the Clima Pro tech off... but even then the Clima Pro tech is just there to maintain a happy medium is it not?


Yeah you could argue that without that line it doesn't tell you much, and seems to support the fact that the clima pro will keep the grinder dialled in pretty much even when very busy.

Would be good for them to repeat it with clima pro off after extensive use.


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## MWJB (Feb 28, 2012)

risky said:


> Someone on the Instagram comments pointed out that tightest range should translate into greatest repeatability shot to shot.


I think that is a bit of a leap. The tightest distribution should correspond to the highest extraction (given the required brew ratio). A significantly wider distribution should correspond to a lower extraction, but if it imposes a certain ceiling that stops you going higher, then that's kind of built in repeatability?

Repeatability (in espresso) is more likely down to basket prep & brew ratio.

EDIT: Looking at Socratic's solubility test, it appears that the Mini, Super Jolly & Robur have the most *repeatable* solubility in that context, but are at the lower end of yield.


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## Dylan (Dec 5, 2011)

risky said:


> Yeah you could argue that without that line it doesn't tell you much, and seems to support the fact that the clima pro will keep the grinder dialled in pretty much even when very busy.
> 
> Would be good for them to repeat it with clima pro off after extensive use.


I agree, although it may well show the same basic characteristics. After all the problem the Clima Pro is solving is the need to re-dial the grinder mid-service, if dialled back in to the target shot time and weight after hours of service it would likely just produce the same results.

Which ditting did they use incidentally?


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## risky (May 11, 2015)

Dylan said:


> Which ditting did they use incidentally?


k804


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## MWJB (Feb 28, 2012)

risky said:


> Am I right in thinking this graph supports that:
> 
> 
> __
> ...


Hard to say for sure...their solubility test is, quite rightly, based on immersion brewing, but there may be differences in uniformity that have a bearing in the chosen grind size range that coincide with those "higher solubility" grinder's modes? x1.4 in mesh size is a fairly big jump in size for a 10 sieve test & certain detail could be missed (variability in particle size centering 215um)...but it doesn't seem to contradict your take on it.

Note the Ditting had the widest variability in the solubility test.

The solubility test only indicates a total range in EY of ~1.5%EY. Statistically, there may be no/little significant difference when assessing the Ditting, Mythos, Major & EK-43 in this example?


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## risky (May 11, 2015)

They are also going to test the ditting KR1403 which will be interesting as it is about double the price of the other K804


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## MWJB (Feb 28, 2012)

None of these charts look right to me. They often seem to show data points at just over 200um, 350um, 550um, 650um & over 900um. But according to the sieves used there are no sieves of these sizes.

"☕No. 20 sieve (841 microns)☕No. 25 sieve (707 microns)☕No. 30 sieve (600 microns)☕No. 35 sieve (500 microns)☕No. 40 sieve (420 microns)☕No. 50 sieve (300 microns)☕No. 60 sieve (250 microns)☕No. 80 sieve (180 microns)☕No. 120 sieve (125 microns)☕No. 200 sieve (75 microns)☕Bottom Pan"

This suggests that certain assumptions have been made about the profile of the distributions captured in each sieve. E.g. that there is always a modal peak centred around the mid value between sieves (between 177um to 250um =215um for example), but the sieving methodology cannot determine this. The data points should coincide with the selected sieve mesh sizes, or could be presented in the form of bell curve.


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## DavecUK (Aug 6, 2013)

DavecUK said:


> I had a look at the chart...but I don't really understand what this all means?


Well....I'm still none the wiser, even after 4 pages. I don't really understand what they did exactly and I certainly don't know what it all means?


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## MWJB (Feb 28, 2012)

DavecUK said:


> Well....I'm still none the wiser, even after 4 pages. I don't really understand what they did exactly and I certainly don't know what it all means?


They ground 100g of coffee, with each grinder. Then sieved each 100g through the stated sieves to see how the particle distribution worked out (how much weight of coffee in g, therefore % of the coffee ground, was captured by each sieve) after 20 minutes of shaking.

Sieving is a 70year old method of analysis for coffee grinds, it is/has been employed by the US dept of Commerce, CBI/CBC, SCAA, ECBC, & grinder manufacturers like Bunn, MPE Chicago & Mahlkonig, but less so nowadays especially for espresso. However, typical sieve time was 5 minutes & the sieves are usually arranged in a uniform order of increase in mesh size, so Socratic's results are only comparable to their own results...which is fine as their protocol is stated (just a query about why certain peaks appear where they do).

In short, what it means is, to get 40g of espresso out of a 20g dose in ~33sec takes a grind with less big particles in it for a Mythos One, Mazzer Major, EK-43...than it does for a Mazzer Robur/Kold, or HG-1 (more big particles).

The tighter the distribution (smaller range of particles), the easier it is to hit high extraction yields, possibly longer shots. The wider the distribution (bigger range of particles) you may get a lower EY, but also a shorter shot for a given strength. It doesn't mean one type is better, or worse, but might be informative depending on what you like & are aiming for.


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## risky (May 11, 2015)

@MWJB have you approached them with your query? They pride themselves on accuracy and impartiality so I'm sure they would look into it for you.


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## MWJB (Feb 28, 2012)

Not about this specific query, but about other queries regarding the sieving protocol & other tests. The charts are published now & discussion ensues, it's happening here, so I'm happy to continue it here.

It's more of an observation than a query, the peaks don't match the sieve data points, this is obvious. E.g, in the Ditting's original chart there are 2 data points of 50g, plus 2 more data points...so where is the extra coffee coming from? The charts don't look like any other sieve results charts.


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## GlennV (Mar 29, 2013)

MWJB said:


> It's more of an observation than a query, the peaks don't match the sieve data points, this is obvious. E.g, in the Ditting's original chart there are 2 data points of 50g, plus 2 more data points...so where is the extra coffee coming from? The charts don't look like any other sieve results charts.


Aren't they just plotting the weight in each sieve against the midpoint of the bin, ie the mean of that sieve size and the one above (which is fine) and then joining the dots with a smooth curve (which is not, unless they've normalised for the width of the bins).


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## MWJB (Feb 28, 2012)

GlennV said:


> Aren't they just plotting the weight in each sieve against the midpoint of the bin, ie the mean of that sieve size and the one above (which is fine) and then joining the dots with a smooth curve (which is not, unless they've normalised for the width of the bins).


Who knows? If we can't look at the curves & make sense of them, how can any other commentators, not used to seeing how these things are usually presented?


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## DavecUK (Aug 6, 2013)

MWJB said:


> They ground 100g of coffee, with each grinder. Then sieved each 100g through the stated sieves to see how the particle distribution worked out (how much weight of coffee in g, therefore % of the coffee ground, was captured by each sieve) after 20 minutes of shaking.
> 
> 1. Sieving is a 70year old method of analysis for coffee grinds, it is/has been employed by the US dept of Commerce, CBI/CBC, SCAA, ECBC, & grinder manufacturers like Bunn, MPE Chicago & Mahlkonig, but less so nowadays especially for espresso. However, typical sieve time was 5 minutes & the sieves are usually arranged in a uniform order of increase in mesh size, so Socratic's results are only comparable to their own results...which is fine as their protocol is stated (just a query about why certain peaks appear where they do).
> 
> ...


1. Yes I was aware it was quite an old method and one that doesn't take proper account of Geometry. e.g. two particles that pass through the same screen mesh have the same sieve size, but may

have very different volumetric sizes

2. That's the measured result, but big in terms of what, because geometry is not considered. Volumetric size is not necessarily the same. Grinders producing different shaped particles could be a major affecting factor

3. Again distribution based on sieves using a spherical volumetric size dimension to interpret the results. The assumptions made with respect to coffee grinding/production may or may not be valid.

Without any account of particle shapes, I think the potential for error is massive. In addition different coffees need "finer"/"coarser" grinds to get the same sort of extraction in an espresso machine. What happens to particle shapes when this happens...I suspect they change. It's why I don't really know what this test is telling me, well I do know it's telling me that geometry must have a big effect, because of what you state in point 2....but no more than that really.

Still it seems to be generating a lot of discussion..


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## MWJB (Feb 28, 2012)

2. Bigger in terms of each grinder's (or group of similar grinders') relative median particle size (midpoint particle size over the distribution).

3. Both sieving & laser diffraction are valid within the industry, we all own equipment that has been subjected to such tests.

There wasn't any attempt here to get the same extraction yield across the grinders, nor would there likely be. It would be a bit like banging a square peg into a round hole?

I'm not sure where in point 2 that geometry is indicated as having a big effect in producing a given shot mass, from a given dose, over a set time (the metric here)? It's beyond the remit of these tests & particle size analysis in general. They probably do have different particle geometries (& that would be interesting to know), yet all but the Ditting still achieved the target. Indeed, both sieving & laser diffraction have limitations with regards to determining particle shape, but that's not what they're aiming to do, they're just aiming to shed light on particles averaged size distribution. When beans are broken down to the region of 28,000 particles per gram, for 100g, x multiple tests, the average dimensions should fall out in terms of % of the ground weight.

Particle shape analysis is possible, but obviously more involved & providing its own detail. Colin Harmon's presentation on the Mythos One touched on this, for instance.


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## risky (May 11, 2015)

I suppose that refers again the to EY test where they analysed the same size particles and how well they extracted.

However when I say "same size" they used a single sieve so there are a range of particles in that sieve. If you have one grinder that is producing the majority of particles at the bottom end of that sieves size and another grinder that produces particles mainly at the top end it isn't exactly a like for like comparison?

Although I don't think there is anything they could do to make that situation any better.


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## risky (May 11, 2015)

@MWJB looks like other people must have been asking the same thing:


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http://instagr.am/p/_DtXIJSuP2/


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## jlarkin (Apr 26, 2015)

MWJB said:


> The new Peak burrs look like they have something in common with the Ditting 804 burrs.


Kyle Ramage from Mahlkoenig said, in a podcast, that they're an 804 burr that re-cast with steel burrs and slight tweaks for the production version


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## MWJB (Feb 28, 2012)

risky said:


> @MWJB looks like other people must have been asking the same thing:
> 
> 
> __
> http://instagr.am/p/_DtXIJSuP2/


Still looks odd, no mention of 1000um sieve in the past, nor a sub 75um sieve, only 10 sieves. Notice a kink where there is bunching of the sieve meshes due to a non-uniform selection in sizes.


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