another_jim wrote:Thanks. My main problem is whether the graphs the distribution is of counts or particle volumes. If it is volumes, the curves are comparable to espresso grinders, the effects will be be subtle, and the analysis will be difficult. If the curves show counts, then these grinders are producing less fines by several orders of magnitude, and the effect should be obvious.

I believe that they are counts. Some of the graphs on his blog have the raw count data that was produced by the QICPIC instrument.

It's still possible that the counts could have been used to calculate and graph volumes. But there was no indication or suggestion that this had been done unless the label "q3" on the y-axis was intended to signify that that the distribution counts have been converted to volumes.

Below is a Marco graph that directly compares an espresso (Vario) grinder to two bulk grinders. And a link to the original (full size) graph.



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They are counts. Reading through his blog, I found where this was explicitly stated. The "q3" apparently refers to the confidence level (third quartile) that the raw counts were sorted into the correct classes.

The count data appears to have been converted into volumes before being graphed

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Thanks. It's almost certainly particle volumes, since espresso grinders produce (order of magnitude) about 10 to 100 times as many fine particles as coarse particles (how many crumbs for each slice of bread?). On the other hand the graphs look a lot like those shown in Illy for volume, although there the fines volume peak is at 80 microns, not 40.

"Q3" cannot be a confidence interval, since that would be shown as a band around the distribution line or as a simple +/- number if it is homogeneous over the entire distribution. It is customary to produce readouts for count, surface area and volume; so perhaps q1 would be count, q2 surface area, and q3 volume.

But whatever the details, if the Vario is representative of all espresso grinders, then it's clear the top bulk grinders produce a far tighter coarse distribution and about half the fines.

I've been drinking more regular coffee since I got into pourover this Summer. I've also been thinking of doing my home roasting more seriously, and I would like to get into cupping. I had this thread in the back of my mind for a while, and I recently noticed a practically brand new Bunn G2 available locally for a great price. It is kind of enormous, but I don't mind leaving it in the laundry room. I'm wondering whether it's worth buying, though.

I just read through the thread again and noted that a lot of people seem to be using the LPG grinders. Nick says he doesn't even think the G-series produces a better cup than the Baratza Virtuoso, which I already own. I also recall some discussion about popcorning problems with the big hoppers. I would like to single dose; is this an issue? Am I going to see a benefit in grind quality, or is it a waste of money?

I use a Bunn LPG. It has the same burrs as the G series, but a smaller motor. It is also in a vertical rather than horizontal configuration. It has popcorning problems, and requires some modding for single portion grinding. Bulk grinders like the Bunn G-series do not have popcorning problems, and grind single portions with elan. They are used in CQI/SCAA accredited Q-cupping labs.

Grinders need to be compared by adjusting each to deliver the same solubles yields in identical brewing protocols, then distinguishing grinder in triangle tests. Nobody has even come close to doing this; it is not a trivial task. Until that point, saying one grinder is better than another is simply anecdotal.

I have not compared the LPG to the Vario. I **anecdotally** prefer it to smaller Baratza and capresso grinders, as well as to espresso and hand grinders.

You mentioned the Vario, which is something I hadn't considered (I was talking about the Virtuoso, which I also own). I thought I would end up selling it, but it might make a fairly good dedicated pourover/cupping grinder, and it isn't 26" tall... hrm.

Bob_McBob wrote:I just read through the thread again and noted that a lot of people seem to be using the LPG grinders. Nick says he doesn't even think the G-series produces a better cup than the Baratza Virtuoso ...

The important point, which Jim already explained, is that we can form tentative conclusions about which grinders work better, but this is still anecdotal. You can't be certain without rigorous testing. I've done direct taste comparisons between the Bunn & a handful of other decent grinders and believe that the Bunn is better than all of the espresso grinders for brewed coffee. But while the difference seems apparent, it's still possible that there might be nonobvious confounding issues. So without formal testing, I won't claim certainty.

I believe that for brewed coffee Ditting > Bunn > Macap MXK, Cimbali MH & Cimbali Jr.
If I make the assumption that the Virtuoso isn't superior to say a Macap MXK. Then it seems likely that the Bunn would also be better than the Virtuoso for brewed coffee.
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I have used several MACAP's, the Mazzer mini, super jolly, major, kony, robur, Fiorenzato or two, a couple different LaCimbali's, among other espresso grinders and did not care for the press pot or drip pot I got from any of them. I do however like the pot I get from my BUNN. It also helps that I have a Bunn plumbed in drip pot so I just put my measured dose in the hopper, slide the filter basket onto the holder and hit the grind till it is empty. Not filling a cup then filling the brew basket makes it more convenient and less messy.

Doing a real study with multiple grinders and identically prepared batches of coffee is a lot of work. More than I have time for so for now this is simply my opinion based on nothing more than taste and observation. The Bunn does a better job than any of the espresso grinders I have used for making drip/press pot coffee. I would love to try a Ditting and compare it to the BUNN but I dont have $3K sitting around to get one.

cannonfodder wrote: I would love to try a Ditting and compare it to the BUNN but I dont have $3K sitting around to get one.

Not sure if you are referring to the Ditting K805. It is ~ half that price:

http://prima-coffee.com/content/mahlkon ... ee-grinder

The flavor I get at home with the Tanzania (Ditting K805) does not compare with the one I get at work (Grindmaster) with the same beans. I get a sweeter, not bitter, better flavor. At work I even use better water (Deerpark) than at home (filtered).

Cheers