Measurement of espresso machine performance

[Abe Carmeli]

Split from Prototype La Marzocco G3 - A Pro's Perspective by moderator...

And, to be honest, that is what I will continue to do. 'Cause that is what it's all about.
I'm doing the WBC style Scace measurements purely because people asked for them.
Honestly, it seem rather silly to me. Once I get it all out of the way I'll be happy.

If there is a machine out there which produces beautiful tasting coffee but tests incredibly poorly when it comes to various technical measurements I'd call it a good machine. This isn't some sort of "spec beauty contest."

It's all about the coffee.

Temp measurements are not really for the numbers sake. The purpose here is to try to investigate what it is in the machine that induces great shots. Look at it as an opportunity to unveil the mystery. A detailed look at the temperature profile allows us to speculate with a little more confidence, since we already have a lot of temp data from other machines to compare it to. It does not give a definitive answer, other things go into it from the machine's performance, but it is a start.

[Walter]

I'd actually love to just leave it at that because I have to tell you all this measurement crap is really boring.

Just drop it and settle for the coffee!

Somehow these "measurement-orgies" remind me of trying to get a grip on the beauty of a statue by breaking it down into pieces, and puzzling over chemical analyses of the marble in the various parts...

Is there word on when the baby will actually be available on the market?

[MOSFET]

Your attempts so far at temp measurements are appreciated. They are not easy, and you probably don't have good equipment and experience. Thousands of pseudo-accurate measurements are a waste of time. This job best be left to someone else. In my opinion, the factory itself should be touting its temp stability and backing it up with good numbers from good equipment. Espresso is the result of pressure and temperature, all other factors remaining the same. There's no magic. So if we belittle its importance we're left with nothing except a couple of reviewers who say they love the coffee that comes out of the machine and a million photographs. This, without technical data, puts the machine on par with machines whose owners over the years have spouted how great their shots are -- machines like Silvia, Andreja, Gaggia, Isomac, etc. Not long ago everyone and his brother bought a Silvia because of great reviews. Subjective taste reports are somewhat useful, but should be a small part of a meaningful machine evaluation, in my opinion. I say let Scace have a go, at the very least.

Keith

[malachi]

Your attempts so far at temp measurements are appreciated. They are not easy, and you probably don't have good equipment and experience. Thousands of pseudo-accurate measurements are a waste of time. This job best be left to someone else. In my opinion, the factory itself should be touting its temp stability and backing it up with good numbers from good equipment. Espresso is the result of pressure and temperature, all other factors remaining the same. There's no magic. So if we belittle its importance we're left with nothing except a couple of reviewers who say they love the coffee that comes out of the machine and a million photographs. This, without technical data, puts the machine on par with machines whose owners over the years have spouted how great their shots are -- machines like Silvia, Andreja, Gaggia, Isomac, etc. Not long ago everyone and his brother bought a Silvia because of great reviews. Subjective taste reports are somewhat useful, but should be a small part of a meaningful machine evaluation, in my opinion. I say let Scace have a go, at the very least.

Keith

1 - It's all about the coffee.
2 - You should probably try to avoid making assumptions about people's backgrounds, experience and abilities unless you know more about them.
3 - Temp measurements are, in fact, easy (assuming you have the right equipment). The problem is that they are boring and tedious - especially when the results are both consistent and predictable.
4 - If someone believes it's all about the coffee then perhaps they don't place the same value on objective measurements as you do.
5 - "all other factors remaining the same" is, I assume, an ironic joke.
6 - While there is "no magic" there is a degree of complexity that approaches what many would call "magic".
7 - More importantly - there is Art.
8 - It's all about the coffee.
9 - Espresso is not "the result of pressure and temperature." It is the result of decades of experimentation and experience and practice coupled with tons of blood and sweat from the famers.
10 - Taste is profoundly personal and subjective. Taste is all that matters in espresso.
11 - Because... it's all about the coffee.

[another_jim]

1 - It's all about the coffee.
...
10 - Taste is profoundly personal and subjective. Taste is all that matters in espresso.
11 - Because... it's all about the coffee.

With all due respect, when I'm cooking for someone, it's all about the food; when I'm describing my pans, it's all about the heat conduction and form. The GS3 is the pan, not the food.

[MOSFET]

1 - It's all about the coffee.
2 - You should probably try to avoid making assumptions about people's backgrounds, experience and abilities unless you know more about them.
3 - Temp measurements are, in fact, easy (assuming you have the right equipment). The problem is that they are boring and tedious - especially when the results are both consistent and predictable.
4 - If someone believes it's all about the coffee then perhaps they don't place the same value on objective measurements as you do.
5 - "all other factors remaining the same" is, I assume, an ironic joke.
6 - While there is "no magic" there is a degree of complexity that approaches what many would call "magic".
7 - More importantly - there is Art.
8 - It's all about the coffee.
9 - Espresso is not "the result of pressure and temperature." It is the result of decades of experimentation and experience and practice coupled with tons of blood and sweat from the famers.
10 - Taste is profoundly personal and subjective. Taste is all that matters in espresso.
11 - Because... it's all about the coffee.

2. I was being polite. Based on your questions on this thread alone I know enough about your level of experience.
5. Other factors include issues such as bean quality and tamping preparation.
9. Everything about why your coffee tastes great will boil down to temperature and pressure assuming you tamped right and your beans are good quality. Alright, maybe you also prewarmed your cup. Research and good design and components went into this machine for what reason? To maintain a stable temperature and pressure. What else? Seriously. Tell me what else.
10. Yes. But your taste is useless to me. My friends love the taste from their Krups machine. That's why it's called subjective. You are subject to the taste and I am not. Temperature stability is useful to all because it's objective and we know that it strongly influences flavor.

If it's all about the coffee and not what goes into making the coffee then you should be posting on a tasting forum and evaluating beans and not machines.

[terryz]

Your attempts so far at temp measurements are appreciated. They are not easy, and you probably don't have good equipment and experience. Thousands of pseudo-accurate measurements are a waste of time. This job best be left to someone else. In my opinion, the factory itself should be touting its temp stability and backing it up with good numbers from good equipment. Espresso is the result of pressure and temperature, all other factors remaining the same. There's no magic. So if we belittle its importance we're left with nothing except a couple of reviewers who say they love the coffee that comes out of the machine and a million photographs. This, without technical data, puts the machine on par with machines whose owners over the years have spouted how great their shots are -- machines like Silvia, Andreja, Gaggia, Isomac, etc. Not long ago everyone and his brother bought a Silvia because of great reviews. Subjective taste reports are somewhat useful, but should be a small part of a meaningful machine evaluation, in my opinion. I say let Scace have a go, at the very least.

Keith

Ouch!

Dang I think I resemble that remark.

Other than myself with a Scace device as well as the help of Stumptown tech, Ken with his Scace device, you're right Keith.....No tools, No equipment


Good thing Greg will be acting as the designated Temp engineer, at least this way you will be able to feel vindicated.

Espresso is many things..............One must look beyond the fog in the window to see clearly.

[lennoncs]

I think we are too focused on temperature;

temperature is very important but it is only a single aspect of machine performance.


where is...

Pre-infuse pressure?
Pre-Infuse Time?
Ramp to extraction pressure?
Time at pressure?
Pressure decay or increase during shot?
Flow rate of the shot?
Pressure/ Time relationships?
Grind?
Distribution?
Roast?
Etc.


We are hung up on the temperature measurements and ignoring a whole host of other measurements that should be made to complete the picture of machine performance.

What if you have 2 back to back shots..one good, one bad...same temp...who was the culprit then?

We are trying to characterize a very complex process and make conclusions after measuring only a single aspect.


Sean

[HB]

We are trying to characterize a very complex process and make conclusions after measuring only a single aspect.

I've been mulling over the same thought after collecting data using your Mr. Wizard pressure/temperature kit (described in Pressure profiles, preinfusion and the forgiveness factor).

One lesson I took away from my first go-around with your kit was that pressure profiles don't say a lot about the "forgiveness factor" even though that's continuously cited as the raison-d'etre of the E61. Andy's (paraphrased) comment really sunk in: It's the grouphead, stupid. Other physical factors like dispersion pattern, top-and-bottom clearances, and who-knows-what else are potential major contributors I've wrongly discounted (*). I have the nagging feeling we're looking in the wrong place, and I don't know how to measure the right place (other than uhhh... tasting). The notion of carefully manipulating the pressure profile intrigues me though...

(*) Lino and I will run some more trials using the Mr. Wizard Kit on Counter Culture's stock Linea, if only to see if there's something worth seeing.

[lennoncs]

The notion of carefully manipulating the pressure profile intrigues me though...

Me too....Blew the bottom out of an LM double basket last night using the Servo/Linear

I was tweaking a servo parameter and had the "safety" off streaming some motion data...bad move. I can get ramp times to .3 seconds but controlling overshoot was a bit of a challenge...all better now

I will say that the composite group has taken a more of a flogging than I expected it would withstand.

Work lately has been centered on profile generation and how to specify the profile; for instance; using arc segments /radius to specify characteristics for a given pressure segment.

Sean

[MOSFET]

Ouch!

Dang I think I resemble that remark.

Other than myself with a Scace device as well as the help of Stumptown tech, Ken with his Scace device, you're right Keith.....No tools, No equipment


Good thing Greg will be acting as the designated Temp engineer, at least this way you will be able to feel vindicated.

Espresso is many things..............One must look beyond the fog in the window to see clearly.

Took me a while to see where this thread blew to.

I'm confused. Are you and others working with Chris? I have not read a lot here lately. From what I've read about the Scace device it sounds like a good standard. Though if you're limited to 0.1 degree resolution and this machine can outperform that you need better equipment. On the other hand if the machine can do better than that then that already speaks volumes.

(than that then that? ...Sorry)



Keith

[malachi]

Heh...

Yeah - Terry was here and ran the machine through its paces the other day.
The machine is pushing the limits of the Scace + Fluke without a doubt.
Intra-shot stability is looking really good as is inter-shot stability. Standard Deviation is looking ridiculously low.
Profile looks like a GB5 profile.


I love that I'm now seen as some sort of Luddite. Very funny given that most people in the coffee world consider me a super techie geek. Must be the decade in high tech engineering management.

[malachi]

Sean - I could not agree more.

I think that pressure is the current frontier and better understanding of pressure (in particular stability and profile) is going to yield some great insight and results.

I'd also love to see some more effort going into the chemistry of espresso. This seems to be a serious focus in Europe whereas here in the US we seem to really be looking at the physics side nearly exclusively.

In general - I'm a huge fan of measurement. Without it we're just guessing. Measurement, to me, is one of the fundamental keys in developing a better understanding of what is going on. But fundamentally I don't believe that measurement is profoundly valuable in evaluating equipment past a certain point of usefulness. For example, if I were choosing between a Marzocco Mistral and a Synesso for a coffee bar I would not be basing that decision (at all) on measurements (other than, perhaps, dimensions). Both are sufficiently temp stable given the current understandings and goals. Now... if I were choosing between a bone stock Linea and a Synesso then yes, measurements would come into play - but not at a granular level.

To sum up - I feel like temp measurements are incredibly valuable when it comes to understanding espresso. Examples would be comparing various brew temp profiles and the results in the cup or comparing the results from a sufficiently temp stable machine to one that is not sufficiently temp stable. Once you have this level of understanding (which I assume pretty much everyone here does) then I think other factors become more valuable.

[terryz]

I'm confused. Are you and others working with Chris? I have not read a lot here lately. From what I've read about the Scace device it sounds like a good standard. Though if you're limited to 0.1 degree resolution and this machine can outperform that you need better equipment. On the other hand if the machine can do better than that then that already speaks volumes.

(than that then that? ...Sorry)



Keith

Actually Keith we have a huge underground espresso lab here in the great Northwest. Most of us are so damn busy tasting the coffee we forget to share the info

The great part about this machine and the company developing it is that they have asked for opinions. It is a rare opportunity to get in on that kind of action, so heck yeah, we are all working together to insure that when this baby goes to market, it is the best it can be for the job it is being asked to perform.

The Scace device is a great tool, that I use everyday. It allows me to bench machines with a consistency that was never before available. Use
of the device on the GS3 was simply for verification purposes. I'm kind of old school with regards to all of the technical aspects of espresso machine testing and tend to spend more time on functionality and taste of the coffee. All the statistics in the world will not change the results in the cup.

The "Holy Grail" of temperature stability has been found in the last two years, so now where do we go? Sean L. seems to think it is in the pump / pressure, and maybe he is right, all I know for sure is that allot has changed in the last two years and it is all good stuff. Statistics aside, I find shear joy and happiness in the simple fact, that someone is paying attention and doing something to raise the bar commercially.

[AndyS]

Work lately has been centered on profile generation and how to specify the profile; for instance; using arc segments /radius to specify characteristics for a given pressure segment.

It's not fair, it's not fair.

[AndyS]

Everything about why your coffee tastes great will boil down to temperature and pressure assuming you tamped right and your beans are good quality.

Damn, Keith, you've dug yourself a very deep hole and you're slowing lowering yourself into it. Haven't you been paying attention?

[another_jim]

Work lately has been centered on profile generation and how to specify the profile; for instance; using arc segments /radius to specify characteristics for a given pressure segment.

Use a straight line profile and an actuator made of physical matter, rather than the divine stuff -- a lot cheaper, same effect, since last time I looked, infinite rates of change were still illegal in this universe.

[malachi]

Sean has all the cool toys.

[AndyS]

Use a straight line profile and an actuator made of physical matter, rather than the divine stuff

Unfortunately, I don't have an espresso machine with an actuator made of physical matter. That kind of equipment is awfully exotic.

[MOSFET]

I think we are too focused on temperature;

temperature is very important but it is only a single aspect of machine performance.


where is...

Pre-infuse pressure?
Pre-Infuse Time?
Ramp to extraction pressure?
Time at pressure?
Pressure decay or increase during shot?
Flow rate of the shot?
Pressure/ Time relationships?
Grind?
Distribution?
Roast?
Etc.


We are hung up on the temperature measurements and ignoring a whole host of other measurements that should be made to complete the picture of machine performance.

What if you have 2 back to back shots..one good, one bad...same temp...who was the culprit then?

We are trying to characterize a very complex process and make conclusions after measuring only a single aspect.


Sean

Ok. Temperature, pressure, and, if you insist, time. But I took time as a given:

Pre-infuse pressure? PRESSURE
Pre-Infuse Time? TIME
Ramp to extraction pressure? TIME/PRESSURE
Time at pressure? TIME/PRESSURE
Pressure decay or increase during shot? TIME/PRESSURE
Flow rate of the shot? TIME/PRESSURE
Pressure/ Time relationships? SIGH...
Grind? TIME/PRESSURE
Distribution? TIME/PRESSURE
Roast? BEEF? MARINATED? SOUNDS GOOD.
Etc. TIME/PRESSURE/TEMPERATURE

sorry, I'm in a silly mood. Blame it on black label.



Keith