In the second part of this in depth look at the WBC certified sponsorship espresso machine, we put a WBC-spec Nuova Simonelli Aurelia through its paces and have a closer look at how a heat exchanger handles temperature stability and changes.
MarkPrince Moderator Joined: 19 Dec 2001 Posts: 5,478 Location: Vancouver, BC Expertise: Professional
Espresso: KvdW Speedster Grinder: Compak K10 WBC Vac Pot: A bit too many Drip: Clive Coffee Drip Stand Roaster: Hario Glass Retro Roaster
Posted Mon Apr 20, 2009, 1:41pm Subject: Re: The Nuova Simonelli Aurelia, Part 2 by Mark Prince
Wanted to give much thanks to Klaus Thomsen, Sammy Piccolo, and many pros that were in the WBC chat session on ustream on Thursday for giving me good background and things to test for when I went into ECM's showroom on Thursday afternoon to check out this machine and run some tests on it. I felt I was more aptly prepared to put the machine through its paces.
Posted Sat Apr 25, 2009, 6:23pm Subject: Re: The Nuova Simonelli Aurelia, Part 2 by Mark Prince
RE: the 0.05 bar adjustment test. Are you sure you let the machine stabilize before taking your final temperature read? I'm still surprised you got a 2F drop from 0.05 bar.
RE: temperature stability. I think your articles would be more useful if you clearly distinguished between: (1) InTERshot temperature stability (following the same temperature profile from shot to shot), and (2) InTRAshot temperature stability (how much temperature variation there is during one shot).
Michael_Teahan Senior Member Joined: 15 Jan 2004 Posts: 135 Location: Los Angeles Expertise: Professional
Vac Pot: Vintage for collecting only Roaster: None
Posted Fri Jun 5, 2009, 3:15pm Subject: Re: The Nuova Simonelli Aurelia, Part 2 by Mark Prince
The undiscovered territory here lay in the dual flow restrictors in the heat exchanger that allow for custom temperature profiling. The WBC likes level temps in both inter and intra testing. The jetting allows for different static group temperature setting (as noted), but also ramp up recovery and HX bias to change the extraction temperature during the shot. Techs hate to mess with this because the HX tubes come out, but it is an unexlpored feature in the engineering of the machine that allows for fiddling with the elusive and controversial temperature profiling a few of us die-hards think is pretty cool.
The use of the PID to control pressure instead of temperature is actually a plus; temp controllers on HX machines suffer when steam is drawn from the boiler, resulting in a lag time and wide temperature swings. Its easy to keep temp within 1 tenth of a degree when no one is actually using it to make a 20 ounce mocha. This is something that Simonelli found in testing, that temp based PID's were less accurate. A .05bar swing is about .75 of a degree Fahrenheit, but the nature of PID's is to maintain a tighter target. Using pressure allows for quick responses to steam demands while keeping temp stable.
PHXcoffee Senior Member Joined: 29 Jun 2009 Posts: 1 Location: phoenix Expertise: I like coffee
Posted Mon Jun 29, 2009, 9:16am Subject: Re: The Nuova Simonelli Aurelia, Part 2 by Mark Prince
Mark - great indepth article, i am learning all the time! i am opening a coffee shop in PHoenix, home to the hardest water this side of the colorado river...and am trying to determine the best fit espresso machine. i have looked at the Rancilio 6e 2 group automatic, the Nuova simonelli 2 group automatic, and the Astoria Perla. your comments about the Aurelia seem to suggest that in a rush, pulling shot after shot, it may not hold the consistancy, what is your opinion vs the other two machines?
do all the Nuova Simonelli Aurelia's have the PID and do you have to look for WBA Certified? are they all certified?
Droshi Senior Member Joined: 10 Jan 2007 Posts: 112 Location: Texas Expertise: I love coffee
Espresso: Bezzera BZ07 Grinder: OE Pharos
Posted Thu Feb 24, 2011, 5:09pm Subject: Re: The Nuova Simonelli Aurelia, Part 2 by Mark Prince
I must have missed this in the past, but going over commercial machines this name keeps popping up. Is there any real good comparison of commercial machines for us crazy home-users that want to splurge? :)
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