The bean breaking section of the burrs holds a shot to a shot and half worth of beans. So the tamper does not weigh the beans down for the bulk of the grind, it just stop them flying out of the grinder. The tamper is standard procedure to use on when single dosing with the conveniently sized 60mm throat of the mazzers. Some other plug is used on grinders with a different throat size. I unironically use an old cylindrical pepper grinder to seal the throat of the Compak.

I am puzzled why you are offering a critique on this experiment if you have never single dosed in your life. How about just the question: "how do you single dose?"

danetrainer wrote:Jim, I am confused about your method used for "single dose grinding"

So, how does this single dosing allow the beans to "move about unobstructed"? Am I missing something?
The outcome is rather what I would have expected with the test conditions.

The Mazzer upper burr carrier has a set of three indents, presumably used to bear the weight of the hopper.

When grinding single dose, the tamper sits on these indents. The volume of 16g of beans just touches the tamper; as such, the tamper doesn't apply any appreciable weight to the bean column. I've had comparable results by using an empty basket.

-s.

another_jim wrote:In sum, the tasting convinced me that for any shot you can produce with a hopper, you can produce the same tasting shot without one, or vice versa, providing you take enough pains. But the difficulties of setting up convinced me that the process for staying consistent with a hopper and without one are different enough so that one or the other can be a lot harder for changing combinations of coffee, machines, and grinders.

+1 on this and thanks for doing this test. I liked your procedure and thought it well-suited to testing what you wanted to.

I think it's well-established in my mind that people can make both grinding methods work equally well, and all the evidence I am seeing so far from our semi-botched testing (Jon and I have had 2 botched tests now, both times thanks to coffee either too early for prime or just not roasted for espresso). I'm sure it's the case that much of these differences people observe are a result of the predispositions of either their equipment, their shot preparation methods, or both. Given all of this, I've pretty much lost interest in trying to get a successful blind taste done between Jon and me; failures have already cost enough time and effort for something that, to me (and Jon too I think) really doesn't seem to hold much promise.

So, I'm prepared to leave this 100% to personal preference, and say that my advice on single vs. hopper dosing is that it behooves every curious/interested person to try it each way; the level of effort required for this is so trivial. You really just use one for a few days and then the other to see which yields you results you're happy with more consistently, with all your own priorities (taste, consistency, ease of use, waste, etc.) considered. Perhaps there's more to say on the issue, but I sure don't know what. I'd still love if John (or anybody else with access to similar equipment) can study single dosing vs. hopper dosing at that microscopic level to perhaps give us some ideas on what's behind the change, but beyond that I see less and less of interest in this controversy every time I approach it.

Sherman wrote:The Mazzer upper burr carrier has a set of three indents, presumably used to bear the weight of the hopper.

I believe those 3 spots are to 'house' the tapped holes for the upper burr mounting screws.

In the weeks leading up to this test, I had been quietly experimenting at home with both methods. My test protocol was similar to that which Jim described, only with a lonely Isomac Rituale instead of a pair of Elektras, and with my SJ instead of the Compak WBC grinder. I chose a coffee with which I've become familiar over the last few months, a 2009 Sidamo Gerbichu Lela. This is the same crop and roast level that I brought to the Bezzera BZ07 testing.

Despite my intentions and continued efforts over a span of about 3 weeks, I couldn't coax a difference out of the bean, and was really hoping that this experiment with Jim would shed light on a missing piece of the puzzle.

For better or worse, the results were pretty consistent. If there are people who can discern the difference, then more power to 'em. I couldn't tell when alone with my equipment and the Sidamo, couldn't tell with my SJ and Jim's Elektras and either his blend or my Sulawesi, and couldn't tell with the Compak and the Elektras.

another_jim wrote:In sum, the tasting convinced me that for any shot you can produce with a hopper, you can produce the same tasting shot without one, or vice versa, providing you take enough pains. But the difficulties of setting up convinced me that the process for staying consistent with a hopper and without one are different enough so that one or the other can be a lot harder for changing combinations of coffee, machines, and grinders.

+1

I'm not going to claim that there is an absolute right or wrong way to go about it, but I'll go so far as to say that you can get similar results with either method, and the benefits of single-dosing as Jim mentioned will keep me on that track.

I know that I can consistently pull tasty fruity doubles from the Sidamo with my SJ set for single dosing, then switch to the Sulawesi, pull another nice shot, and then switch back to the Sidamo, all in the same session, and with a minimum of fuss.

-s.

another_jim wrote:... if you have never single dosed in your life.

...I am puzzled where that assumption came from?

Anyway, I mostly single dose...and have followed all of the posts in the different Topics involving it.
I saw many posts speaking of "single dosing" such as pouring the measured amount into the grinder throat as the burrs were spinning...and other unweighted means.

I had found a big difference in consistency after adding a "weight" above the dose of beans in my small, custom hopper. I had been chasing grind settings all over the place when switching coffees or amounts of beans, then finally found an answer when the Topic by Ian surfaced "A Tamper is Too Heavy for Grinder Anti-Popcorn Remedy".

If the tamper aids in feeding the beans into the burrs...(my assumption from your comment: weighed down with a tamper. )

If the tamper only keeps the beans from flying out...and adds no weight, then I understand the test.

Jim, I also, very much owe a lot to your findings & advice... Thank you for sharing so freely your knowledge and findings!

Yeah, I've missed that people are using tube shaped nano-hoppers filled with a few doses of beans and a weight. I think this is much closer to hopper grinding than single dosing, since there is a mass of beans covering those entering the grinder, increasing the rate at which they feed.

I'll dispense with all the "thanks for doing this earth shattering study which has bettered the lives of coffee drinkers worldwide and humanity in general" prologue as it has been previously stated a few times

The smaller the potential difference you are looking for, the larger the number of shot pairs you would have to run in order to prove that such a difference exists. Anyone who has ever participated in a study like this will appreciate this unassailable fact.

What this means is that to show an obvious and tastable difference comparing something like grinding practice, you would have to do a hell of a lot of shot pairs, more than any two non-professional coffee people would be willing to endure. This does not mean that there is no difference, just that within reason there is no obvious or huge difference.

I would suggest that these sorts of results could have been predicted in advance, as I am sure that at least Jim predicted before he set up this little study. And, I am sure, that Jim does not think that he has proven for all time that there is no difference, just that the difference, if it exists, is fairly small and not worth the time (or at least his and Sherman's time) to demonstrate. There are simply too many variables in this sort of experiment to detect a small but real difference without (probably) a few hundred shot pairs, and even then the difference, if you found it, would not be huge.

I would propose that this study really should not have much or any impact on how any given individual decides to use their grinder(s) in the preparation of coffees used to make espresso. This decision will and should be made on aesthetic grounds.

My aesthetic sensibilities in this area is that we are using these huge ass commercial grinders in a home setting, which is not the use that they were designed for. Commercial users of these grinders put a sh*tload of coffee into the hoppers and they grind the same coffee through the same grinder for an extended period of time, always with a bean load above the grinder burrs in the throat of the grinder. I personally prefer to use these grinders in more or less the way that they were designed. I have been and remain concerned that when one single doses that one ends up with some of the last coffee one ground for the prior shot in the new shot with the new bean type that one is grinding this time. And whether or not I could taste this in a blind tasting is irrelevant for me. When I'm making a shot of 14g of some particular Ethiopian SO, I want as much of the 14g as possible in my PF to be that aforementioned coffee. Period. And I don't care if the 2g of something else that might be in there might be imperceptible to me; I just do not want it in there, period.

If I wanted to change coffees more frequently, then I'd buy two grinders instead of one, even if it meant buying 2 lesser grinders instead of one terrific grinder. That is just me and just how I approach this sort of thing. As I have posted previously in another thread, with two grinders one could comfortably drink three different coffees each day, changing the contents of each grinder every other day, reducing both coffee waste and the unintentional melanging of coffees as the beans change.

This study will give support to anyone who grinds coffee in whatever fashion they grind it. It will be quoted in the future as giving credence to the idea that there is no difference, no matter what you do. But there is a difference, it just isn't necessarily a sensory difference, but an aesthetic one. That doesn't make it any more or less important, rather that just puts it into its proper place, and in this case a decision on what any individual should do should in my view be a "gut level" one rather than being a "scientifically" guided one.

ken

Ken Fox wrote:I would propose that this study really should not have much or any impact on how any given individual decides to use their grinder(s) in the preparation of coffees used to make espresso. This decision will and should be made on aesthetic grounds.

I'd agree with this, finding the choice of beans not the most revealing and also the protocol less than ideal in changing back and forth between grinding modes and settings, in "storing" the four shots per round, in swirling and resting the shots to negate the differences between the machine pumps (if this evens the taste differences between the machines it could be doing the same thing with respect to differences between grinding modes) and possibly the use of small hoppers, depending on the weight of beans they held.

I consequently don't find this test to be more scientific or valid than anecdotal evidence, despite it having been a blind test.

In fact, I find Sherman's comments on his experiences with the Sidamo in his Super Jolly more interesting. I have noted only a very small difference with this bean in the SJ, and consider this grinder ill-suited to revealing the nuances in a Sidamo - in fact I have in other threads commented that I actually prefer my Lehnartz hand grinder for this bean (or of course the Nino).

Being entirely in agreement with Jim's comments and caveats regarding the differences and overlaps between Titan and almost-Titan grinders at different doses and with different beans in the TGP and Can it beat the Robur threads (which I remember even necessitated a revision of the scoring as testing progressed), I think any potential differences in taste profile between single-shot and hopper dosing need more careful, extensive and protracted scrutiny than they have received here.

Cheers

Mike

michaelbenis wrote:I consequently don't find this test to be more scientific or valid than anecdotal evidence, despite it having been a blind test.

Of course everyone is entitled to an opinion.
My view is completely opposite this one, and in fact I find this remark amazing.

michaelbenis wrote:I think any potential differences in taste profile between single-shot and hopper dosing need more careful, extensive and protracted scrutiny than they have received here.

I respectfully disagree as to the necessity, but to each his own.

It seems fairly clear to me at this juncture that the differences to be gleaned are very subtle at best (if any inherent difference exists at all). I suppose I do agree that if such differences are to be distinguished it probably would take "extensive and protracted scrutiny"

The problem would be, of course, attempting to keep any "extensive" study objective and maintaining isolation of one variable being studied....but I will leave that to other more interested parties.


As Ken said, the results here are probably not sufficient to convince anyone to change regimen and so it follows logically that the same might be said about people's views not being changed as well.

michaelbenis wrote:I think any potential differences in taste profile between single-shot and hopper dosing need more careful, extensive and protracted scrutiny than they have received here.

JonR10 wrote:It seems fairly clear to me at this juncture that the differences to be gleaned are very subtle at best (if any inherent difference exists at all).

These last posts remind me of The Princess on the Pea. That is, if the difference between A and B is small enough that it requires "careful, extensive and protracted scrutiny" to detect, my interest in pursuing it further is similar to the other minor performance/technique variants listed in the aforementioned Princess thread (read: zero).

A note on comparison tests elaborates on the number of trials necessary to demonstrate differences that are obvious versus those that are subtle:

another_jim wrote:As far as coffee tests are concerned, my guess is that people are hardly interested in making a change if it turns out not to beat their current set up at least 6/10 times. Unfortunately, even that requires more trials (75 to 200) than any of us amateur testers can easily handle. So, if we discover no difference, it's somewhere from 30/70 to 70/30, and if we do discover a difference, it's because its more extreme than that.

The point being that there may be a real difference between hopper and single grind dosing, but it's not significant enough to prove without more trials than most home baristas are willing to perform.