Scace and the Aurelia
If you follow these kinds of things you will be aware that the Nuova Simonelli Aurelia is the new competition machine for Baristas. When the question of sponsors for the WBC has come up in the past, people wanted to know if any company other than LaMarzocco would ever have their machines used in competition. The answer seemed to come back that if anyone else’s machine could pass the WBC’s strict temperature stability prerequisite, they would be considered for the machine sponsorship. Many machines on the market now boast either dual boiler or some other technology intended to maintain a constant brewing temperature. One can assume that the Nuovo Simonelli Aurelia delivers the temperature stability that they claim.
If you look at the transparent view they provide on their website you can see just enough confusing imagery to get that they do not want you to understand how they achieve stability in any real transparent way. The description explains the following about each group: they weigh 12 pounds each, they hold a liter of water, the brew water passes though a heat exchanger, there is only one heating element. This is how I believe it is designed to function (my best guess anyway). Water that is heated by the heat exchange is passed into the one liter reservoir located inside the group itself. The massive group is gently heated by siphoning water from the steam boiler. Because it takes so much energy to change the heat of the group and reservoir, the temperature remains relatively constant.
I had the opportunity to test an Aurelia with a Thermofilter. The machine had been idle for at least 15 minutes when I started, and I flushed the group to listen for any signs of super heating. The water came out with a hiss, which lasted for as much as 20 seconds. A traditional heat exchange might have hissed for half this length of time (at least from my experience). I flushed for another 10 seconds and found the temperature to be 209F, still to hot for good extraction. Another 10 seconds of flushing brought it down to between 198 and 200. There was a gently inclining temperature profile over the time of the shot.
Once the machine was brought down to a desirable temperature it did maintain it very well. If the machine stays in constant use it will stay relatively stable. A couple of idle minutes, however, and it was back to 209. There is a lot of flushing needed to keep it within brewing parameters if there are interruptions between coffee prepartion. There is a steep learning curve with the Aurelia, as with any heat exchange machine. One must use it a lot and taste the coffee it makes a lot and become intimate with it to get what one wants from it. The winners of the Barista Competitions coming up will be Baristas who have spent time testing heat exchange machines. The winner of the WBC will be someone who spends a lot of time with the Aurelia and a Scace device and really learns the proper flush times. The massive groups give up heat reluctantly, which is both the advantage of and the Achile’s heal of the Aurelia.
This makes me wounder if the WBC has rigid temperature standards at all. If this is the new competition machine then it seems obvious that they do not. I can’t say that I blame them for going with Nuova Simonelli though. It is terribly expensive to put on even small competitions, and the head sponsor has to flip an enormous bill. The competition machine will be form the one that offers the largest kitty, not the one with the easiest machine to use. This will weave out the Baristas that have been raised into the coffee industry with equipment that is so good that they have not had to learn some basic lessons in brewing equipment management. The winner will be an even better Barista than one who simply expects the machines to do the brunt of the work for them. I know that great coffee can be made on heat exchange machines, but it takes a great Barista. This year the cream will not rise to the top until after it has passed through a strainer.
The Aurelias need to be set up properly to work optimally. The WBC-spec Aurelias that we worked on last week are pretty bad-ass, actually.
Dear Sir,
The Aurelia is extemely stable. You only need flush or purge it for one to two seconds max. I know it is different from the LM. If you purge for too long you will bump up the temp as you experienced. Unlike standard hx machines running the group will not cool it down unless yourun it for a long time but that is totally misusing the machine. Greg Scace himself did the testing.
Thanks Nick, it is true. I have been informed by WBC members that the competition machines are tweaked way out, and that the street version of the Aurelia is not as temperature stable. Please let me be clear on certain points:
1- I have a great deal of respect for the WBC and I do not wish to imply that they make back room deal, receive kick backs, or conduct their business without standards. I was surprised that what I saw in the Aurelias currently available did not seem consistent with what I would expect for a competition machine. (Competition spec machines will be in production after the Championship)
2- I believe that the WBC should get as much money in sponsorship deals as they can. These thing are way expensive, and we may not be having some or our regionals this year because of lack of sponsorship.
3- I would be thrilled to go head to head with any Barista on a heat exchange machine, any where, any time, any how (cage match if necessary).
Roberto,
If you are referring to the machines built for the competition, which Greg Scace tested, the results of my testing should not apply, as they are apparently very different form the Aurelias already in place in shops now.
I do not wish to give the impression that I was not able to use the Aurelia with satisfaction. On the contrary, after purging and temperature testing I did get the rhythm of the machine and I was able to pull a fantastic shot of espresso (New Harvest Bicycle Blend). The steaming was also exceptionally good.
Phil, you’re still a little off-base.
The WBC-spec machines are set up for 200*F, 9 bars, 1.0-ish bar steam boiler pressure, with selected baskets, steam-tips, etc. They aren’t “tweaked way out.” They’re simply optimized for WBC specs. Any Aurelia could be set up similarly.
The way the HX environment in the Aurelia achieves the temp stability that it does is frankly a lot to wrap my brain around, and it is dependent on many factors. Don’t mistake this fact with a mysterious souped-up WBC machine… it doesn’t exist. In fact, such a thing was against the rules of the WBC technical evaluation. It had to be a commercially available machine. No one-offs or special tweaks were allowed.
As mentioned, baskets and steam tips were spec’ed out for WBC. Otherwise, these are stock 3-group semi-auto machines.
Well in that case, there must be some significant setting up to do that is outside of the reach of the average shop owner, because I was getting anything from the low 190s to 209. To me, stability means you can walk up to the machine and engage the pump, and Whamm!,… you get the temp you set it up to be. The Aurelia I tested was up and down dependent on flushing times and idle times. Flushing brought it down, idle periods brought it up. This occurred more slowly than traditional heat exchange machines I have worked with, which is nice if you stay busy. However, you can’t tell me that flushing times have to be exactly so-and-so seconds, not to exceed so-and-so seconds, and expect to make me believe it is temperature stable. That is the very definition of Temperature Surfing, and it is the hallmark of heat exchanger temperature fluctuation.
What does it mean to “optimize” this machine to get it to hold a constant temperature?
Just found this thread as I prepare for the upcoming Canadian Nationals in Montreal, Oct 21,22nd. Nice blog Phil. Just to give you some background. We in Canada have used the Aurelia the for the past two nationals, and this year will make it three years in a row.
I first came across the Aurelia at the 2005 SCAA. The heavy engineering had been already done, and the fine-tuning had begun. I was impressed enough to follow up with Nuova Simonelli,and based on the technical performance, we announced the Aurelia as our 2006 National Championship machine sponsor.
Since then, other countries have followed suit, but our Canadian baristas can be proud of the fact that we were the first to recognize the temperature stability of the Aurelia and the first to compete nationally on the new hx technology.
There was some controversy, as many competitors were only familiar with dual boiler machines. However, as baristas practised on the machines, they started to see and taste the engineering.
In a nutshell, if you try to use the Aurelia like a typical HX machine.. ( ie.. flush to cool), you will totally destabilize this machine.
The Aurelia is a no-flush machine. If you flush excessively, you will actually heat the head, raising the temperature of the brew water. Some baristas use this feature to their advantage to up-surf a degree or two. However for the purposes of the competition, we instructed our competitors to just do a “cleaning flush”.. ie. a quick blip of the pump, just to clean off any stray grounds on the group screen… just one second. The purpose of the flush is not for temperature regulation.
This is opposed to the usual temperature regulating flushes on La Marzoccos upon a long idle( up surf to compensate for a cooling grouphead ), and non-aurelia hx machines ( cooling flush to compensate for a heating group head/ thermosiphon).
Try this method the next time you are at the helm of the Aurelia, blip-flush for a second (RESIST THE URGE TO PURGE!!), and then brew your shot.
Fyi, if you excessively purge, and overheat the head, all you need to do is to switch groupheads, and by the time you’re done pulling your shot on the second group ( 90-100 seconds) , the first group will return to equillibrium.
Btw.. what is the pressurestat reading?
Since this post came out my research has lead me to the discovery of the different valve set-ups available on the Aurelia. Many of the machines in use now have the traditional heat exchange set up where temp surfing is necessary. The set up for the WBC machines can be found in some machines, and these are as you and Roberto have described.
The Aurelia I used in this test did not heat up with flushing, but did cool off as I would have expected from a HX.
Thanks for the input. I would very much like to try out one of the temperature stable Aurelias someday.