La Marzocco GS3 Thermal Performance Quantified - Page 2

[cinergi]

I'll run another set of WBC tests on my synesso once I get a new pump later this week (there's a problem with my current pump).

With the messed up pump (which admittedly may not affect temp) the best I'm getting on my synesso is a reproducibility score of: + - .57F


Doug

[MOSFET]

http://www.lucidcafe.com/cafeforum/graphtwo.html

This graph from his #27 article shows that after about three seconds (9 data points) it reaches the stable region, and then it's between 203.1 and 203.4 for the entire rest of the shot. The graph, which I don't know how to reproduce here, shows considerably more stability than the ones posted above.

He also says "The data shows a 1/2 degree of basic error with most shots varying about 3/10ths of a degree F during the 25 second event." And his graph shows that. Does he say somewhere else what data points he throws out? And why would he need to do that if it is so flat to begin with?

Keith

[malachi]

Need to compare apples to apples.

In the case you're referencing, he is measuring through the banjo bolt rather than in the portafilter.

[cinergi]

He also says "The data shows a 1/2 degree of basic error with most shots varying about 3/10ths of a degree F during the 25 second event." And his graph shows that. Does he say somewhere else what data points he throws out? And why would he need to do that if it is so flat to begin with?

Keith

He says in his "techniques of the barista" DVD that he throws out the 1st 10 sec. due to error or something. In that video he is using a fluke with a K type probe at the top of the puck.

Unless he has modified his synesso's they do not reach a stable level until the approx. the 8th sec.

Doug

[cinergi]

Here's a typical shot from a 1 group synesso:

set point was 201.5F

When I look at graphs of stable machines the biggest difference I see among them is the 1st 8 sec. or so. Maybe this is why Schomer throws out the 1st 10. However, as Greg as stated so many times, the water is hitting the coffee during the 1st 10 sec. so those data points are important. The glaring difference between the synesso and the GS3 seems to be the starting temp (i.e. 184 vs. 195). The higher the starting temp the sooner you'll reach the stable point which is going to affect the scores.

184.5
185
192.3
200.1
200.5
200.3
201.1
201.3
201.4
201.4
201.5
201.3
201.3
201.5
201.7
201.9
202.1
202.1
202
201.9
202
201.9
201.9
201.9
202

average thowing out 1st 3 sec. = 201.5

[malachi]

Measured how?
Scace + Fluke?
WBC protocol?

Probably best to provide context (the 2 shots on each side) as well.

[cinergi]

Measured how?
Scace + Fluke?
WBC protocol?

Probably best to provide context (the 2 shots on each side) as well.

WBC protocol using Scace + Fluke 54 II

[barry]

Need to compare apples to apples.

In the case you're referencing, he is measuring through the banjo bolt rather than in the portafilter.

at least on my marzocco, there was a pretty tight correlation between banjo bolt probe temp and scace device. there was some offset, of course, but the shot temp variation was pretty tight.

here's one series of shots:

[malachi]

But note the far faster ramp up on most of those shots...

[barry]

But note the far faster ramp up on most of those shots...

clarify?

[malachi]

Sorry - your ramp up from the Banjo Bolt is very fast (which is logical) as compared to the Scace measurements.

This is the trouble with comparing results from one measurement method, location and tool (not to mention protocol) with results from an entirely different system. And it's a great argument for the value of the Scace.

[barry]

Sorry - your ramp up from the Banjo Bolt is very fast (which is logical) as compared to the Scace measurements.

that's the main reason greg specifies the first three seconds should be ignored.

it was nice to see the correlation, though, as not only did it test greg's device, but it also validated the banjo bolt probe as a good measurement site.

[lennoncs]

And it's a great argument for the value of the Scace.

I like the Scace; his device is pretty cool also

Congratulations Greg, your device is well on its way to becoming this generation's "Kleenex"

I would like to see temperature data overlaid(sp) such as Greg's first graphs, it helps me visualize a bit better.

Sean

[AndyS]

the device is at the cake and is the Ewenohoo device for sure.

I thought the name "Eponymous Device" was kind of cool, especially if there are any English majors or other folks who like big words reading this board.

But hey, it you want to stick with "Ewenohoo," it's OK with me.

I was talking about the variance one see on the display, which seems to get pretty well attenuated by the time the water comes out'n da group.

Bill C's opinion was that 1 or 2 degrees variation where the temp probe is located (in the boiler) doesn't have much of an effect on the actual brew temp. It IS a marketing problem, though, because people who are paying $4500 not only expect to get stability, they expect to SEE stability on the display so they can brag about it to their friends.

The display variance is also a minor problem for the barista, because it's easy to forget what your setpoint is, and the display doesn't tell you without a lot of scrolling.

And yes, the measurements suggest that the limit of taster sensitivity to temperature might be more than the 0.3 degrees. I'm guessing it's more like .6 degrees or so (root sum of the squares of 0.3 and 0.5 actually).

Sorry, I don't understand your point there. Could you re-explain it for poor old me? Thanks.

[AndyS]

Andy, I think he's built a few more than the Colorado outfit.

Who has, Sean, or LM?

[another_jim]

Who has, Sean, or LM?

Sean seems to be have modded a several Brewtuses at this point. However, I'm not sure how many more of the circulation pumps he's installed, which is what gets that last one degree C stability.

[lennoncs]

4 have PIDs installed

Only one Brewtus has a circ pump

at the moment...

sean

[MOSFET]

4 have PIDs installed

Only one Brewtus has a circ pump

at the moment...

sean

I've been really interested in the circulation pump idea. Can you give me the gist of it and/or provide a good link to discussion?

thanks
Keith

[gscace]

Sorry, I don't understand your point there. Could you re-explain it for poor old me? Thanks.

Chris said that his assembled multitude of pros could tell 0.3 degrees temperature variation in taste, but the reproducibility of the machine is at the half degree level. IF you take the square root of the sum of the squares of 0.3 and 0.5, the value is approx. 0.6 degrees. So I'm ballparking that if the Pros can actually discern a difference, it's gonna be at the .6 degree level, not .3.

-Greg

[malachi]

Blind taste tests indicate otherwise.