I don't want to, and don't intent to, disparage the wonderful work that Jim and Ken have done but Mark is not the only one who has found results that do not sync up with their results. The trouble is that the primary advantage (in the cup and IMHO) of the rotary pump is also dependent upon excellent temp management and stability, a specific brew profile and coffee selection. If you have a flat(ish) brew profile, good temp management and are using a high-quality coffee the difference in clarity in the cup between the two will be noticable (again, IMHO).
Posted Tue Nov 8, 2005, 9:07am Subject: Re: Introducing the La Marzocco GS3
malachi Said:
I don't want to, and don't intent to, disparage the wonderful work that Jim and Ken have done but Mark is not the only one who has found results that do not sync up with their results. The trouble is that the primary advantage (in the cup and IMHO) of the rotary pump is also dependent upon excellent temp management and stability, a specific brew profile and coffee selection. If you have a flat(ish) brew profile, good temp management and are using a high-quality coffee the difference in clarity in the cup between the two will be noticable (again, IMHO).
Frankly, if the calibration of the two machines was not first adjusted to eliminate as many other variables as possible, it's a meaningless comparison. Do you have a link to any tests in which the machines were properly set up ala Jim and Ken, yet still found the rotary consistently made better espresso? Please don't take this as being argumentative. That rotary pumps make better tasting espresso is long-standing element of espresso lore. Ken and Jim "validated" it in a 2003 test, when they found the rotary made better tasting shots. But after experimenting with the vibe pump setup on his Isomac, Jim suggested they re-do the tests after equalizing other aspects of the machine setup. The result put this piece of espresso lore in doubt. If you have links to other carefully conducted tests that contradict the "tale of 2 Juniors--Part Deux", please post them. If you don't, on what are you basing your opinion that the rotary is better? Do you have a theory about what pressure/volume characteristics of the rotary make it better?
Posted Tue Nov 8, 2005, 9:09am Subject: Re: Introducing the La Marzocco GS3
AlMac Said:
I took two points away from Jim and Ken's work: on an absolute basis (ie all things properly equalised) there's no discernable difference; and you have to frig around a bit to get to the state of 1. so for most punters it isn't going to happen.
malachi Senior Member Joined: 5 May 2002 Posts: 1,735 Location: se portland, or Expertise: Professional
Espresso: Mistrals, Linea, Briccoletta Grinder: Roburs, Super Jollys,... Vac Pot: Hario, Bodum, Cona Drip: never Roaster: Probat 60kg, 15kg, 5kg,...
Posted Tue Nov 8, 2005, 9:49am Subject: Re: Introducing the La Marzocco GS3
Rick Said:
Frankly, if the calibration of the two machines was not first adjusted to eliminate as many other variables as possible, it's a meaningless comparison. Do you have a link to any tests in which the machines were properly set up ala Jim and Ken, yet still found the rotary consistently made better espresso? Please don't take this as being argumentative. That rotary pumps make better tasting espresso is long-standing element of espresso lore. Ken and Jim "validated" it in a 2003 test, when they found the rotary made better tasting shots. But after experimenting with the vibe pump setup on his Isomac, Jim suggested they re-do the tests after equalizing other aspects of the machine setup. The result put this piece of espresso lore in doubt. If you have links to other carefully conducted tests that contradict the "tale of 2 Juniors--Part Deux", please post them. If you don't, on what are you basing your opinion that the rotary is better? Do you have a theory about what pressure/volume characteristics of the rotary make it better?
For links, check out my blog or my writings on various sites.
Opinion based on 6 months of research, blind taste testing and experimentation on top of years of professional experience.
Theory - yes. Stability of pressure (i.e. reduction of "flutter" or variation). I've written extensively about this on my blog and on other web sites. Suffice it to say that the only thing that I found frustrating about working on home machines as compared to the high-end commercial machines was that home machines seemed to be incapable of producing the elusive "clarity in the cup" that I found in espresso from certain commercial machines. After much experimentation I found that this seems to be related to a combination of brew temp profile and stability and brew pressure profile and stability. I have been incapable of producing such clarity from any vibe pump machine, but have produced it from rotary pump machines when set up correctly (isolated pump from input variance, "flush and go" temp surf, very clean machine). Of course - it also depends on the coffee you're using.
Oh... and Mark and I are not the only people who have tasted a difference. And I'm not the only one with the "clarity" theory (talk to John Bicht for example).
Finally... the rotary pump still, IMHO, has flaws. I would love to see more research on other pumps (in particular on linear hydraulic, air piston and linear piston pumps).
runt Senior Member Joined: 5 May 2003 Posts: 95 Location: Beautiful Colorado Expertise: I love coffee
Espresso: Señor Brewtus Grinder: Mazzer Mini E, zassenhaus Vac Pot: bodum santos Drip: press pot, no drip! Roaster: Gene
Posted Tue Nov 8, 2005, 10:02am Subject: Re: Introducing the La Marzocco GS3
I wanted to mention that Brewtus pre-heats the water that enters the brew boiler. There is a heat exchanger in the steam boiler that the water runs through. In previous posts, it seemed to be implied that there was no pre-heating of the brew water with Brewtus. Shot after shot, with my husband and I both working the machine, we've never had to wait for boiler recovery. Of course, on the scale of speedy baristas, we're both pretty slow.
Just an FYI.
I can still love my Brewtus and admit that the GS3 is in a league of its own. (Brewtus will never know!)
A silly side question, is the GS3 going to have the amazing users manual that LM is known for?
Posted Tue Nov 8, 2005, 10:15am Subject: Re: Introducing the La Marzocco GS3
malachi Said:
For links, check out my blog or my writings on various sites.
Opinion based on 6 months of research, blind taste testing and experimentation on top of years of professional experience.
Theory - yes. Stability of pressure (i.e. reduction of "flutter" or variation). I've written extensively about this on my blog and on other web sites. Suffice it to say that the only thing that I found frustrating about working on home machines as compared to the high-end commercial machines was that home machines seemed to be incapable of producing the elusive "clarity in the cup" that I found in espresso from certain commercial machines. After much experimentation I found that this seems to be related to a combination of brew temp profile and stability and brew pressure profile and stability. I have been incapable of producing such clarity from any vibe pump machine, but have produced it from rotary pump machines when set up correctly (isolated pump from input variance, "flush and go" temp surf, very clean machine). Of course - it also depends on the coffee you're using.
Oh... and Mark and I are not the only people who have tasted a difference. And I'm not the only one with the "clarity" theory (talk to John Bicht for example).
Finally... the rotary pump still, IMHO, has flaws. I would love to see more research on other pumps (in particular on linear hydraulic, air piston and linear piston pumps).
Thanks, I will check out your blogs in a little more detail. However, I haven't been able to find one that contains all the words "espresso pump rotary vibratory". Any suggestions on what I should search for?
Also, you haven't mentioned whether the tasting you (and any others you've read about) conducted was blind tasting from otherwise identical machines with the pump pressure, debit and brew temperature set as close to one another as possible. Did your tests and the others on which you base your belief include this step?
Finally, if rotary pumps are superior to vibe pumps, I would expect rotaries and vibes to produce a different waveform. I would expect both to produce an oscillating pressure, but I don't know the shape of the wave, nor do I know the frequency or amplitude. Do you know how the waveforms generated by these two types of pumps differ as installed in espresso machines?
malachi Senior Member Joined: 5 May 2002 Posts: 1,735 Location: se portland, or Expertise: Professional
Espresso: Mistrals, Linea, Briccoletta Grinder: Roburs, Super Jollys,... Vac Pot: Hario, Bodum, Cona Drip: never Roaster: Probat 60kg, 15kg, 5kg,...
Posted Tue Nov 8, 2005, 10:27am Subject: Re: Introducing the La Marzocco GS3
There is extensive research on the "oscillation" patterns in the various pumps. Home-Barista (for example) has a bunch of folks who have researched this - and, of course, alt.coffee has probably a couple of decades of research experience and a dozen or so people who can speak at length about both their theories and actual, practical results. Or you can talk to John Blackwell et al and get the benefits of their experience. The folks at Illy would also be good candidates for results. John Bicht at Versalab - David Schomer at Vivace. Terry Z at Espresso Parts. Any and all of these folks are likely to have the sort of graphs and results you're looking for. I'm an amateur compared to any of them.
Hey Mark... Any update on taste tests? You need some other coffees to work with? Would love to see some results and some testing a la the list I provided earlier...
Posted Tue Nov 8, 2005, 10:59am Subject: Re: Introducing the La Marzocco GS3
I'm not aware of anyone except Jim and Ken who have posted a rotary vs. vibe blind (sort of) taste test in which the brew pressure, water debit and brew temperature have been equalized on both machines. The results of such tests would help to clarify whether there is a real difference in espresso quality produced by rotary vs. vibe machines. Does anyone have a link to such a test?
MarkPrince Moderator Joined: 19 Dec 2001 Posts: 4,663 Location: Vancouver Expertise: Professional
Espresso: Frankenstein'ed LM Linea Grinder: Anfim Super Caimano Vac Pot: 1922 Silex Drip: Krups Moka Brew Roaster: Hottop
Posted Tue Nov 8, 2005, 2:00pm Subject: Re: Introducing the La Marzocco GS3
malachi Said:
Hey Mark... Any update on taste tests? You need some other coffees to work with? Would love to see some results and some testing a la the list I provided earlier...
Taste is all subjective, of course, and mainly just me now... but soon I will be setting up a few "open houses" (hope to get Rick to one of them!) where I'll be doing some blind tasting comparisons with one or two other machines. I'm working on the questionaire this week for it.
Coffees used will most likely be Black Cat and Kidd-O. But I may arrange to get a few other top notch espresso blends to toss into the mix.
MarkPrince Moderator Joined: 19 Dec 2001 Posts: 4,663 Location: Vancouver Expertise: Professional
Espresso: Frankenstein'ed LM Linea Grinder: Anfim Super Caimano Vac Pot: 1922 Silex Drip: Krups Moka Brew Roaster: Hottop
Posted Tue Nov 8, 2005, 2:13pm Subject: Re: Introducing the La Marzocco GS3
Rick Said:
I'm not aware of anyone except Jim and Ken who have posted a rotary vs. vibe blind (sort of) taste test in which the brew pressure, water debit and brew temperature have been equalized on both machines. The results of such tests would help to clarify whether there is a real difference in espresso quality produced by rotary vs. vibe machines. Does anyone have a link to such a test?
My most formal test in this regard was done for a company as paid work, and the results were for their internal use. It'd be up to them if they want to post this informationp publicly. But I can tell you the result - definite difference in the quality between a vibe and pump machine.
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