Do ultra precise brew temperatures really matter? - Page 2

[JimWright]

Don't the Synesso machines allow this?

[iZappa]

I thought there were a number of commercial machines that allow the groups to be set to different temperatures. The NS Aurelia is one,

The NS Aurelia does not have that ability. You can insert three gicleurs in it to influence the temperature (two in the group and one on the flowmeter exit). But since it is a huge HX you will not be able to get the same temperature shot after shot. It is very stable though through a shot. Replication of the exact temperature is hard on the Aurelia.

[pdx]

Don't the Synesso machines allow this?

Yes, each group on a Synesso has its own boiler & pid setting. So a 3-group could give 3 simultaneous temperatures.

[bernie]

FWIW, I have an idle LM 4group that is scheduled to have dual PIDs installed this summer. Not sure when I will get to that as we are putting the finishing touches on a new bakery and bagel kitchen. It will be kicking my butt for a while I'm certain. But, when the machine is done I will offer it up for such a test. It is one big muthah. I'd need someone to arrange moving it to wherever the testing takes place. Maybe a road trip from someone.
Bernie

[John P]

Short answer.

Yes.

Having used a LM Linea for 15 months and then using a Synesso for 2+ years now, I can say not only does the stability matter, but the control over it matters as well. That's not to say that a specific declining temp profile may not do wonders as well, but for targeting select sweet spots in various espresso it makes a remarkable difference.

This statement by Malachi during his GS3 testing days has always stuck out to me.

You're right about the massive difference a single degree temp change brings. I'm actually noticing huge differences at even 0.3F changes. And that is an eye-opening statement.

Prototype La Marzocco GS3 - A Pro's Perspective

[HB]

This statement by Malachi during his GS3 testing days has always stuck out to me...

A couple points make me really wonder about the statement that anyone can "notice huge differences at even 0.3F changes."

First, that's smaller than the error limits of most lab quality temperature measurement equipment (e.g., my type T thermocouple, Fluke 54-II), let alone the onboard sensors on the GS3. Just because it says 200.3 on an LCD display doesn't mean the actual boiler temperature is precisely the same. Secondly, the temperature spread between the top of the puck and the bottom of the puck is several degrees. The two temperatures don't meet until the final seconds of the extraction. So given the extraction temperatures (plural) progress over a range and that range doesn't narrow until the last third of the extraction, is it logically plausible that a fraction of a degree over this multi-degree temperature spectrum is critical? Not everything can be reduced to numbers, but intuitively I would say no.

Furthermore, are there many individuals who (a) have sufficiently developed barista technique such that minute differences in brew temperatures are the leading factor behind flavor profile shifts, and (b) are capable of tasting the subtle change in taste caused by a fraction of a degree change in temperature? Again, intuitively I would say no.

[AndyS (original poster)]

This statement by Malachi during his GS3 testing days has always stuck out to me.

Of course, that statement has always stuck out to many of us. Particularly since it is doubtful that the GS3 prototypes in circulation at the time were delivering temperatures that were repeatable to 0.3F

And John Bicht made the statement that a 0.05 bar change in brew pressure made a significant difference in taste.

But IIRC, neither John's nor Chris's observation was the result of blind tasting.

[HB]

And John Bicht made the statement that a 0.05 change in brew pressure made a significant difference in taste.

I apply the same layman's analysis to John's statement. The brew pressure at the top of the puck is 9 bar... and a lot less than 9 bar at the bottom of the puck. So a brew pressure spectrum varying from 9 bar to the exit brew pressure at the bottom of the puck is impacted by a 0.05 change in pressure? Yet again, intuitively I would say no.

[AndyS (original poster)]

Yet again, intuitively I would say no.

<sigh> Another "thought experiment."


(Your "intuition" is not the result of blind testing).

[HB]

(Your "intuition" is not the result of blind testing).

That is my exactly my point: Unless it can be demonstrated in a blind taste test, such statements should be treated with skepticism on the basis of a "thought experiment" alone. In contrast, if someone had claimed "I can taste a brew temperature difference of 3F", I would accept it without demonstration.