Is single dose [without hopper] grinding inconsistent?

[Ken Fox]

...split from Titan Grinder Project by moderator...

The level of modding at this point seems a bit over the top. What are the boundary conditions imposed on the tests? Seems to me that the folks using them have little experience with them and are trying things willy nilly. I can tell you that both the Kony and the Robur like having some beans in the hopper. And the hopper fill switch is a non-issue for each grinder since there is a manual override.

Are we testing grinders, or are we testing modded grinders, or are we just modding grinders?

-Greg

This post from Greg Scace has long been buried in this thread, but deserves UNBURYING. I think that Greg made a very valid point and one that needs to be considered in this thread and in all its "derivatives."

It is one thing to mod one of these grinders and give descriptive commentary, yet another altogether to do what appears to be "controlled" testing on grinders that have been severely modded.

Most of these grinders are humongous, and it stands to reason that to whatever extent they will sell into the home market, that they will be modified. On the other hand, they were designed for high volume settings, and certain aspects of their design are potentially critical to their operations within "specs." For example, as Greg pointed out, these grinders are designed to operate with a bean load on top of the burrs, in the hopper.

Granted, you can remove the hoppers with various creative approaches, and attempt to provide the same effect by weighing down the beans entering the burrs with various weighted objects. Although this seems to be a valid simulation of the normal operating condition, is it really? Does this weighted object on top of the burrs simulate a full hopper for the last 5 or 10g of coffee that is being ground for a given shot? A mass of beans on top is going to fill all the gaps above the beans being ground and put fairly uniform pressure on those beans just entering the grinder burrs. A heavy weighted object is going to sit on top of the shaft on which the top burr is mounted and popcorning can occur beneath it in the gap between the heavy object and the burrs. If this was not true, the heavy object (a tamper, for example) would risk being chewed up as the last of the beans are being ground up.

This has particular relevance in what Jim is doing on his "can this beat the Robur" thread, where (I believe) more or less the exact weight of beans desired to be ground is put into the grinder and fully ground. A variable is being introduced that is not being controlled, e.g. the propensity of a given burr set to popcorn under the weighted object, even if it is only the last 5 grams or so of coffee that is effected.

In my own limited experience with my Compak K-10 WBC grinder, I have used mostly a small custom fabricated "mini-hopper" made of common plumbing parts

which nonetheless generally has at least 25 or 50 grams of coffee more than I am grinding above the coffee to be ground, then a weight on top of that. To the left, on the top of the adjacent grinder, is another white plastic plumbing part that I've planned to use for rapid coffee switches in the grinder, with a tamper on top of it. In my very limited use of this "micro-hopper" with a tamper on top of the beans, if I grind all the coffee out and use it, the pours have been inconsistent.

I applaud Jim's efforts in doing this testing and his efforts to find a way to use these grinders for "cupping" type rapid bean type switches. In fact, this was a major reason why I chose to buy the Compak grinder myself. I am coming around to the opinion that probably none of these grinders will function completely normally without at least a modest quantity of beans above what is to be ground for a given shot. Whether this quantity is 5, 10. or 25g, I do not know, but I do think it is NOT zero.

Another factor is that there are grinders that simply cannot be used without a bean load above the burrs; two prime examples from my own experience are the Cimbali Junior/Cadet and Max models. The popcorning that results in trying to use these grinders without a bean load on top has a very obvious, detrimental, effect on the grinds that vanishes as long as a couple of "layers" of beans are on top of those being ground during the grinding process. Because these grinders simply cannot be tested without some "excess" beans on top, is it valid (or fair) to comparison grinders to potentially "handicap" them by operating them without this bean load above the burrs? I think not.

I think it would be better to test these grinders with more than the exact quantity of beans to be ground for a shot above the burrs, if meaningful results that others can rely on, are to be obtained. Purchasing decisions by forum readers are another matter altogether, and this is where the reader has to determine if a great grinder, with all its design imperfections as relates to home use, is a good purchase afterall.

ken

[HB]

I think it would be better to test these grinders with more than the exact quantity of beans to be ground for a shot above the burrs, if meaningful results that others can rely on, are to be obtained.

I agree. Although it wastes coffee, I always have a day's worth of beans in the hopper. Each session is preceded by purging the grinding chamber and then cleaning out the doser. I haven't bothered with single dose grinding in years.

[DavidMLewis]

I agree. Although it wastes coffee, I always have a day's worth of beans in the hopper. Each session is preceded by purging the grinding chamber and then cleaning out the doser. I haven't bothered with single dose grinding in years.

While I agree with Ken about the original design goals of these grinders, I'd like to see the sensitivity to bean load tested and mentioned. One of my prime desiderata in a home grinder is precisely this ability to switch easily among two or three different beans throughout the day, so I personally would like to know if a given grinder's design precludes it.

As an aside for those who have them, how does the Versalab, which is designed to be run empty, handle this? Is its augur given a reflex curve so that once a bean has entered it's pulled through or something?

Best,
David

[Ken Fox]

While I agree with Ken about the original design goals of these grinders, I'd like to see the sensitivity to bean load tested and mentioned. One of my prime desiderata in a home grinder is precisely this ability to switch easily among two or three different beans throughout the day, so I personally would like to know if a given grinder's design precludes it.

As an aside for those who have them, how does the Versalab, which is designed to be run empty, handle this? Is its augur given a reflex curve so that once a bean has entered it's pulled through or something?

Best,
David

Hi David,

How exactly do you propose that this be tested? All of these grinders are going to "popcorn" to at least some extent if you try to grind the last few grams of beans with nothing on top of them. How could you possibly test the importance of this observation? If in one grinder it is the last 5g that popcorns, and in another it is the last 15g, how could you establish this fact and what impact would shot dosing have on it (e.g. 5g popcorned out of a 20g dose is presumably going to have a different impact than 5g out of a 12 or 14g dose). How about the impact of a given espresso machine on the coffee with regards to the particle distribution from non-popcorned vs. popcorned grind percentages?

My opinion is that the only way one could possibly test this is with cupping and not with espresso. Is cupping done with coffee ground for espresso? I don't know, but it was my impression that it was not. I think that the results of any such evaluation are going to be so subjective that they will be useless. So then you would be left with basically someone's visual report on the amount of popcorning they see during the end of the grinding process, which in my view will be about as useful as "eyecupping," e.g. not very.

ken

[another_jim]

Four points:

1. If there is a half pound of beans weighing down every bean going into the grinder -- will that astronomical down force really prevent a bean from popping back out if it doesn't find a gap, and is instead smacked by the 500 to 1800 rpm rotating steel burr mounted to a half horsepower motor? Or will those added beans shorten the distance it travels and muffle the noise? Does popcorn covered by a blanket still pop?

2. Even if you clear out the 5 odd grams in the chute, you still have 3 grams or so in the grind chamber. If you leave the hopper off, you can clear that by pulsing the grinder after cleaning out the chute. If you use a hopper, you cannot, and have to sacrificial grind a second, then clear the doser, before each shot.

3. I did taste tests on this way back when I first got the mini, and Mark Prince dreamed up the popcorning problem (hopperless was pretty much SOP by 1/2 the people on alt.coffee those days.) I could detect no difference. Nor did I notice grind setting changes from a filled hopper to the setups I'm using for the Titan grinders. If the popcorn effect really exists, it should alter the way the grinder works, and there would be a change in setting. Also, the purported popcorn effect should lead to inconsistent pours from shot to shot. Ironically, the only two grinders that delivered inconsistent pours in this test were the Lux, where I kept the hopper filled, since it won't work otherwise, and the M3, which doesn't have a hopper. All of the grinders I "misused" have done just fine in terms of repeatable pours and taste. The last six test pours, using the big conicals I've turned on the two machines, waited 30 seconds, then turned off the two machines simultaneously, the pours are that easy to dial in. The tastes have been close to utterly identical too, and I'm groping for hairs, so I can score them differently. But I'm sure my pours would have been even more consistent if only I had filled those hoppers.

4. People have noticed one change with extreme popcorning, and I accept their observation. They say they need to grind finer. What does that prove? Popcorning shatters beans and creates more fines? Then it would require a coarser grind to offset the extra fines. Simple explanation: the grind is slowed down because the beans enter the burrs at a slowed rate. This means fewer grinds are going through the chute at any given time, and they are less compressed by the passage. When people dose by volume, the slower, fluffier grind will use less weight to take up that volume, and so will require a tighter grind. The effect will disappear if one weighs the doses. The same effect would magically appear if one has a full hopper, volume doses, and changes grind speed on a conventional doser-grinder setup.

As you can guess, I think the purported ill effects of popcorning are a myth. But prove me wrong if you can.

[Ken Fox]

Four points:


As you can guess, I think the purported ill effects of popcorning are a myth. But prove me wrong if you can.

Jim,

Theories and explanations are interesting, but in my opinion, not germane. If we really understood why these grinders act the way they do, then all we'd need to do is remove the burrs, do some measurements, photograph and measure the grind paths and dosers, then plug all our "data" into a mathematical equation and there'd be no need to even taste the shots . . . . .

You place me in an awkward position, that of trying to defend one of Mark Prince's "theories."



Given how "certain" he is about such things as freezing coffee, that is like asking me to explain how Chris Tacy's sensory apparatus can detect 0.1F temperature differences.

Nonetheless, you don't know and you can't possibly know how operating these grinders outside of their design parameters (e.g. without beans on top of those being ground) subtly effects the grind. What you do in your own daily practice is of concern only to you.

But, testers in the TGP are being asked to test these grinders because it simply is impossible to send these grinders around to all participants in these forums. Descriptions coming from you and others working on this project carry weight, because we are asking you to interpret this stuff that we don't have the opportunity to evaluate for ourselves.

If the grinders are being used in a way alien to the way that they were designed, the data "suffers" if by no other way than the perception that it might be tainted.

If the issue is that you don't have enough coffee to test these grinders with, I'm sure that Dan can arrange for a sponsor to send you some more for testing.

Best,

ken

[another_jim]

If the grinders are being used in a way alien to the way that they were designed, the data "suffers" if by no other way than the perception that it might be tainted.

Alien to the way they were designed?!? They were designed to stand in the bar of an Italian railroad station, grinding 12 Kg/Hr, running 45 seconds at a stretch to put 200 grams into the doser.

"Suffers" ? How about repeatedly flicking the doser to empty it-- doser vane whiplash syndrome, call the personal injury lawyers.

Just about everything in home barista-ing is alien to the design of the machines we use. But if my alienating the hoppers really makes people suspicious of my results, they are welcome to ignore them, and rely on the other half dozen people who will check out the Titans. In my opinion, if I had to do these tests in a way out of keeping with my SOP, they would have been less reliable, and I probably wouldn't have taken them on in any case.

[DavidMLewis]

How exactly do you propose that this be tested?

Hi Ken,

I didn't mean to stir up a hornet's nest. The question for me is "can this grinder be used to grind one shot's worth at a time without compromising the taste of the resulting shot, and without wasting a lot of coffee when switching?" On this question, you and Greg seem to have one answer and Jim another, and since I respect the tasting and analytical abilities of all of you, I am at a loss to explain it. Hence my attempt to refine the question: the only explanation I can come up with is that you, Greg, and Jim aren't actually answering the same question.

Best,
David

[Ken Fox]

Hi Ken,

I didn't mean to stir up a hornet's nest. The question for me is "can this grinder be used to grind one shot's worth at a time without compromising the taste of the resulting shot, and without wasting a lot of coffee when switching?" On this question, you and Greg seem to have one answer and Jim another, and since I respect the tasting and analytical abilities of all of you, I am at a loss to explain it. Hence my attempt to refine the question: the only explanation I can come up with is that you, Greg, and Jim aren't actually answering the same question.

Best,
David

David,

I think there are two issues here:

(1) the one you pose, to which I really don't have a well formulated answer,

and

(2) whether the answer to #1 should be assumed rather than tested, and if just assumed and not formally tested, is it appropriate to take the assumption and run with it, in the sense of "embedding it" into a test methodology that is supposed to be formally comparing grinders but might in fact be effected by extraneous factors such as how well a given grinder works without a hopper vs. another given grinder without a hopper.

It might be that some work well and others don't, but that if you used hoppers with some beans in them for testing, you would eliminate that question altogether and could just focus on the grinders.

ken

[another_jim]

David, I've done one after the other tests of hopper and no hopper with every grinder I get, including most of the TGP ones (I only did the little Macap, since the throat on the big one is the same). Grinding speed goes down, noise levels go up, but the grind setting and, as far as I can tell, the shot quality do not change. This is not an experiment, but just a quick test to find out if the grinder is suitable for doserless operation -- see my response to Ken.

Ken, you keep stressing the proper way to use these grinders. This is, to my mind, meaningless, or at least ambiguous.
-- Some people will buy these grinder for busy bars, keep the dosers filled, and be interesting how accurately the dosing adjustment, and how reliably the automatic refill, work. They may also want to know how well a "don't touch the grind setting" policy works over the course of a day. This may be the most proper way of testing the grinders, since that is what the engineers intended, and the market for which they are built.
-- For others, proper usage may be suitability for Barista championships and third wave coffee stores. In this case, the key will be how fast and accurately it dials in, how accurately a timer doses the coffee, how well the doser distributes the grinds into the basket, and how consistently the shots flow. Greg lives in this world, and that is what he wants to know. It is also an entirely proper set of issues
-- For others again, it may be about having one coffee grinder for the home of a coffee lover. It should be useful switching between three or four different coffees, and for espresso, drip and presspot brewing. This is my own need. More importantly, if someone were to ask me how adaptable a commercial grinder is for home use, this is the criterion I think is objectively the correct one to use for its ergonomics. By testing the grinders hopper-less, I'm addressing the questions of this category of user. I think that too is entirely proper.

I choose to test for the third kind of user, since that is who I am. If you think this is self-indulgent, you may be right. But I doubt I'd be of any greater use to the community testing these grinders in some way I don't intend to use them. My heart wouldn't be in it, and I'd be mailing it in.

In any case, I didn't see anyone falling over themselves volunteering to do definitive taste and accuracy tests on the auto-fill dosers

[cannonfodder]

I will toss in my observation with the Kony. The beans most definitely popcorn when there is nothing above the burrs. The beans jump up into the hopper and you can clearly hear the beans jumping around in the grinding video I did way back when.

I kept a quarter to half pound in the hopper when I was using it. During my testing sessions I would grind and pull multiple back to back shots. During those sessions I would occasionally run out of beans in the hopper because I was not paying attention. Those last 'end of the hopper beans' shot would run noticeably faster hence my assumption that the grind changes when the hopper is empty. I believe Dan had the same observation, when the hopper went empty, that shot suddenly ran fast.

However, if the grind was adjusted from the start for that single dose method of grinding, I don't think it would make much difference. I noticed that as long as I had a couple of shots worth of beans in the hopper, plus the one I was grinding so around 45g of coffee, I did not notice a difference.

Jim mentions a press pot, while I did not mention it when I had the Kony I did make a couple of awesome press pots using it.

[miKe mcKoffee]

However, if the grind was adjusted from the start for that single dose method of grinding, I don't think it would make much difference. I noticed that as long as I had a couple of shots worth of beans in the hopper, plus the one I was grinding so around 45g of coffee, I did not notice a difference.

So in a nutshell, sounds like if you want consistent results be consistent. Just like virtually any other aspect of coffee!

[Ken Fox]

Ken, you keep stressing the proper way to use these grinders. This is, to my mind, meaningless, or at least ambiguous.
-- Some people will buy these grinder for busy bars, keep the dosers filled, and be interesting how accurately the dosing adjustment, and how reliably the automatic refill, work. They may also want to know how well a "don't touch the grind setting" policy works over the course of a day. This may be the most proper way of testing the grinders, since that is what the engineers intended, and the market for which they are built.
-- For others, proper usage may be suitability for Barista championships and third wave coffee stores. In this case, the key will be how fast and accurately it dials in, how accurately a timer doses the coffee, how well the doser distributes the grinds into the basket, and how consistently the shots flow. Greg lives in this world, and that is what he wants to know. It is also an entirely proper set of issues
-- For others again, it may be about having one coffee grinder for the home of a coffee lover. It should be useful switching between three or four different coffees, and for espresso, drip and presspot brewing. This is my own need. More importantly, if someone were to ask me how adaptable a commercial grinder is for home use, this is the criterion I think is objectively the correct one to use for its ergonomics. By testing the grinders hopper-less, I'm addressing the questions of this category of user. I think that too is entirely proper.

I choose to test for the third kind of user, since that is who I am. If you think this is self-indulgent, you may be right. But I doubt I'd be of any greater use to the community testing these grinders in some way I don't intend to use them. My heart wouldn't be in it, and I'd be mailing it in.

In any case, I didn't see anyone falling over themselves volunteering to do definitive taste and accuracy tests on the auto-fill dosers

Jim,

I don't want you to do anything that you are uncomfortable with or that your heart isn't in, but:

The other reviewers have done (mostly) descriptive reviewing, which I think is just fine. What they have written is clearly composed of opinions, educated opinions to be sure, but opinions nonetheless. A lot of what you have written also falls into this category and as such is clearly labeled.

What I take issue is the air of science, the whiff of this, that comes from posting precise tasting scores and one on one grinder comparisons ala, "can it beat the Robur?" I don't believe that this is adequately controlled because I believe you are not using these grinders within their "specs," i.e. there is no bean load above the beans that are being ground for the shots you are tasting. If you would more clearly label these tasting results as being your opinion only and perhaps being limited by the hopperless arrangement you are using, then I'd have no issue with any of this.

ken

[another_jim]

I think

And Now for the Entertainment Portion of this Review

as the very first thing I say, is more than adequate to dispel the air of science. The scores are boxing scores, round 1, round 2, etc.

I am adding the detailed scores that I'm keeping for later analysis at Teme's request. Teme is not one of the grinder testers, since shipping the grinders to Copenhagen is somewhat awkward. He is, however, one of the heavy hitters when it comes to this whole review process. He has done exemplary work testing a whole set of grinders there, including publishing and interpreting the first ever enthusiast generated particle size comparisons among top grinders. Dan and the rest of us are eager for any input he might give to the final article. If he wants to see the detailed data, he gets it.

I'll be using the same scoring and data collection format to test pairings of the smaller grinders among themselves. By doing such additional tests, and also using the detailed sheets from the blind sessions I did with Marc, I can check whether the data are mutually consistent and usable. If they are, I'll post a statistical analysis with all the caveats that they are based on hopper-less grinders.

Finally, the other reviewers have done blind testing, not just judgment based impression gathering. I'm not for a moment granting that their results apply only to hopper operation, while mine apply only to hopper-less operation. But if it turns out that our results are fundamentally inconistent, then that may well be the reason, and I'll be eating crow.

But for now, relax, I'm doing a grinding reality show, the non-prime time, summer rerun season, entertainment portion of the review.

[RapidCoffee]

What I take issue is the air of science, the whiff of this, that comes from posting precise tasting scores and one on one grinder comparisons ala, "can it beat the Robur?" I don't believe that this is adequately controlled because I believe you are not using these grinders within their "specs," i.e. there is no bean load above the beans that are being ground for the shots you are tasting. If you would more clearly label these tasting results as being your opinion only and perhaps being limited by the hopperless arrangement you are using, then I'd have no issue with any of this.

Ken, these are valid points. However, as much as I love having a commercial grinder in my kitchen, I would give it up in a New York minute if I had to use my Super Jolly per design specs (i.e., the way it would be used in a commercial establishment). Fill the enormous bean hopper with a kilogram of beans? Keep the doser half full of grinds so that one stroke consistently yields a single dose and two strokes a double? No thanks. Standard commercial practice, but completely unsuitable for the home barista.

A more likely scenario for the home user: store roasted beans in airtight canisters, and grind per shot within seconds of the pour. I see nothing wrong with modifying the equipment in minor ways to achieve this (e.g., losing the hopper or defeating autogrind). Ditto for adjustments to technique (e.g., thwacking the doser). Such alterations to original grinder design specs do a far better job of reflecting typical home use.

However, the question of bean weight in the hopper really should be tested. I'm already slated to run a bunch of particle size analyses. Perhaps I'll add one more comparison: a single shot ground in my SJ with and without the weight of a tamper, in each case adjusting the grinder to give similar pour timings. If the particle size distributions are similar, this would support the hypothesis that weight on the beans is unnecessary. If they're different, it would indicate the need for more study. Would that help allay your concerns?

Dang it, I so do not want to keep a kilo of beans in my hopper...

[Matthew]

I have read all posts in the TGP and related threads. To me it has become evidently clear that it will be extremely difficult to make this a "scientific" test with hard conclusions, even if HB had many more resources. There are so many variables and personal preferences that a definite outcome of Grinder C> Grinder A> Grinder D etc.. is unlikely.
Fortunately, we are still learning quite a bit in the grinder department due the efforts of all testers involved.

I agree with Ken that testing the grinder hopperless is out of the original design purpose and therefore could lead to different results. Nevertheless, the testing of Jim in this thread is valuable because more than a few people do want to run the grinders hopperless and modified.

Some of the remarks, which are most of the time very valid, made in these threads could come off as hostile to the testers.
But I am sure non of these are meant in that way and we all are very appreciative of your hard work. So please keep going

[Ken Fox]

Some of the remarks, which are most of the time very valid, made in these threads could come off as hostile to the testers.
But I am sure non of these are meant in that way and we all are very appreciative of your hard work. So please keep going

I wouldn't worry too much about that. Most of us know each other fairly well, at least through these forums. As for Jim and myself, we have been friends a long while and see each other with some frequency. Jim is actually coming to visit me in about 6 weeks, at which time we hope to do some more formal testing, if we can agree on what is worth testing, that is.

ken

[Ken Fox]

Ken, these are valid points. However, as much as I love having a commercial grinder in my kitchen, I would give it up in a New York minute if I had to use my Super Jolly per design specs (i.e., the way it would be used in a commercial establishment). Fill the enormous bean hopper with a kilogram of beans? Keep the doser half full of grinds so that one stroke consistently yields a single dose and two strokes a double? No thanks. Standard commercial practice, but completely unsuitable for the home barista.

A more likely scenario for the home user: store roasted beans in airtight canisters, and grind per shot within seconds of the pour. I see nothing wrong with modifying the equipment in minor ways to achieve this (e.g., losing the hopper or defeating autogrind). Ditto for adjustments to technique (e.g., thwacking the doser). Such alterations to original grinder design specs do a far better job of reflecting typical home use.

However, the question of bean weight in the hopper really should be tested. I'm already slated to run a bunch of particle size analyses. Perhaps I'll add one more comparison: a single shot ground in my SJ with and without the weight of a tamper, in each case adjusting the grinder to give similar pour timings. If the particle size distributions are similar, this would support the hypothesis that weight on the beans is unnecessary. If they're different, it would indicate the need for more study. Would that help allay your concerns?

Dang it, I so do not want to keep a kilo of beans in my hopper...

For the record, as I've made obvious in pictures I've posted, I'm not using my Compak conical with its original hopper, either, although I have made a point of using it almost all the time with a bean load on top in the hopper I have improvised. My Cimbali grinders do not lend themselves to easy modification, however they are much more "kitchen friendly" in their stock configurations.

There is absolutely no doubt that most of these enormous grinders are out of place in a home kitchen, and if they are to be used in one they will be modified. The one thing I would be loathe to modify, especially in a formal review, would be operating without at least a layer or two of beans above those being ground, as I believe this is one modification that could easily effect grind quality.

Your testing, John, although interesting, would only give us information on the one grinder that you are doing particle size distributions on (SJ), so it couldn't really be generalized beyond that.

ken

[Ken Fox]

I think

And Now for the Entertainment Portion of this Review

as the very first thing I say, is more than adequate to dispel the air of science. The scores are boxing scores, round 1, round 2, etc.

I am adding the detailed scores that I'm keeping for later analysis at Teme's request. Teme is not one of the grinder testers, since shipping the grinders to Copenhagen is somewhat awkward. He is, however, one of the heavy hitters when it comes to this whole review process. He has done exemplary work testing a whole set of grinders there, including publishing and interpreting the first ever enthusiast generated particle size comparisons among top grinders. Dan and the rest of us are eager for any input he might give to the final article. If he wants to see the detailed data, he gets it.

I'll be using the same scoring and data collection format to test pairings of the smaller grinders among themselves. By doing such additional tests, and also using the detailed sheets from the blind sessions I did with Marc, I can check whether the data are mutually consistent and usable. If they are, I'll post a statistical analysis with all the caveats that they are based on hopper-less grinders.

Finally, the other reviewers have done blind testing, not just judgment based impression gathering. I'm not for a moment granting that their results apply only to hopper operation, while mine apply only to hopper-less operation. But if it turns out that our results are fundamentally inconistent, then that may well be the reason, and I'll be eating crow.

But for now, relax, I'm doing a grinding reality show, the non-prime time, summer rerun season, entertainment portion of the review.

Jim,

I think the risk here is that real differences among the grinders could be masked by too many things being fudged. The easiest conclusion to reach in a project like the TGP is that there is no discernible difference, but if there really is one then we are limiting our results to, "it doesn't matter, go buy any decent grinder and you will be fine." Although there is obvious truth to this last sentence, I'd rather have this time consuming TGP show slight differences, which the reader would then be free to decide were not worth paying for, either in real money or in the inconvenience of having such a leviathan grinder in one's kitchen.

ken

[RapidCoffee]

Your testing, John, although interesting, would only give us information on the one grinder that you are doing particle size distributions on (SJ), so it couldn't really be generalized beyond that.

The same observation applies to any study, including your work comparing vibe vs. rotary pumps. I could point out that your results apply only to your Cimbali Junior espresso machines, whatever grinders you used for the study, and that particular batch of beans. Ditto for your more recent article on freezing greens. But those studies are still valuable, providing (at least) a starting point for future investigation. That's all I'm suggesting here.

I think the risk here is that real differences among the grinders could be masked by too many things being fudged. The easiest conclusion to reach in a project like the TGP is that there is no discernible difference, but if there really is one then we are limiting our results to, "it doesn't matter, go buy any decent grinder and you will be fine." Although there is obvious truth to this last sentence, I'd rather have this time consuming TGP show slight differences, which the reader would then be free to decide were not worth paying for, either in real money or in the inconvenience of having such a leviathan grinder in one's kitchen.

All the Titan grinders are more than capable of producing excellence in the cup, so to some extent we're talking personal preferences rather than better or worse. Good grind quality and ergonomics are to be expected from grinders in the $1K price range, and I think the Titans deliver.

I'll be pleased if we reach consensus on a few general issues, such as fundamental differences (if any) between flat/planar burr grinders and conical burr grinders. (And perhaps dispel some of the recent hype surrounding conicals. ) The TGP testers (Dave, Jim, Ken, Dan, and I) have all noticed the high forgiveness factor associated with conical grinders, and that may be one of the most compelling conclusions of the study. Tastewise, there's less consensus - neither Dave nor I are rushing out to buy a conical just yet.