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La Marzocco GS3 and Strada Paddles

Postby rbh1515 on Mon Aug 08, 2011 8:35 pm

A coffee place in town just replaced their 2 group Synesso with a two group LM Strada.
Question--does the mechanical paddle work like the GS3 paddle or is it different (btw, my GS3 does not have the paddle). From what I have read, with the Strada you can change the pressure throughout the extraction. I presume you follow the pressure on the top of the grouphead. Could you do this with a GS3 if it had the gauge. I'm curious to learn more about the machine.
Rob
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Postby HB on Mon Aug 08, 2011 9:02 pm

rbh1515 wrote:From what I have read, with the Strada you can change the pressure throughout the extraction. I presume you follow the pressure on the top of the grouphead.

The Strada MP starts the pump as soon as the paddle is pushed left, but only allows preinfusion via line pressure until the mid-point. Past the mid-point, the full pressure of the pump enters the grouphead. If you have Ninja Barista skills, I suppose you could surf the crossover point between the preinfusion and full pressure line, but in my experience, a more nuanced pressure profile than off-preinfusion-full-on is not reproducible.

This video shows the mechanics of it:


From La Marzocco GS/3 Mechanical Paddle : How it works

If you want to see all the bits and pieces, see the video in New La Marzocco Paddle Service Video:



The Strada EP uses a variable speed rotary pump to control brew pressure; each group can record four profiles and can be run manually. I briefly used the EP before it went on tour:


From Friday mornings at Counter Culture Coffee in Durham, NC

I've not used the GS/3 paddle, but I assume it works like the Strada sans gauge on top (corrections welcome).

rbh1515 wrote:Could you do this with a GS3 if it had the gauge.

Not really, but there's always Wholesale Copying Greg Scace's Ideas for much less than a Strada EP.
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Postby rbh1515 on Tue Aug 09, 2011 2:17 pm

Dan,
Thanks for the response. So for all intents and purposes the GS3 paddle and the Strada MP paddle sound pretty similar--they are either off, line pressure, or on. It sounds like the EP is the one with the true pressure surfing.
Rob
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Postby HB on Tue Aug 09, 2011 2:32 pm

rbh1515 wrote:It sounds like the EP is the one with the true pressure surfing.

That's correct.

For the sake of completeness, the Synesso Hydra has a "4 stage pressure ramping" feature similar to the La Marzocco EP. Based on the demonstration at the SCAA conference, Synesso's approach to brew pressure profiling seemed less complicated than La Marzocco's.
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Postby Carneiro on Tue Aug 09, 2011 3:07 pm

Just a tech detail addition, the Strada EP pump is a (rotary too) gear pump driven by a variable speed DC motor.

I've got two quotes on the MGFR series (a Crouzet 24V brushless DC motor and MG304 pump with PEEK gears) with US companies and it was around USD 500! I think this motor is smaller than the one LM uses, and it could be perfect for home projects, but the price is crazy - if anyone has some other company or maybe a way to buy directly from FOT (maybe a group purchase)... :mrgreen:

As far as I've seen on a wiring diagram the motor speed should be easy to control. I think GS/3 has analog output available but I don't know how easy is to replace the code inside the board. For other machines, an Arduino + extras should make a nice interface. A initial setup could be a complete manual control with pressure gauge feedback to the barista. Pressure profile playback should include a pressure transducer, or maybe a advanced flow/pressure automation could be programmed.

Procon has a interesting small vane pump (MicroVane) with a DC motor - I don't know the price range. Oh, I think I'm going OT...

Márcio.
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Postby Carneiro on Tue Aug 09, 2011 3:21 pm

And about the GS/3 and Strada MP, I think the MP turns the pump before the GS/3, considering the paddle position. So it could be possible to find some intermediate pressure on the MP, but I've never seen any video showing this.
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Postby shadowfax on Tue Aug 09, 2011 4:54 pm

HB wrote:For the sake of completeness, the Synesso Hydra has a "4 stage pressure ramping" feature similar to the La Marzocco EP. Based on the demonstration at the SCAA conference, Synesso's approach to brew pressure profiling seemed less complicated than La Marzocco's.


It is much less complicated. There are 3 pressure settings (line, pump, and pump with secondary bypass). You set the pump pressure like any rotary vane pump espresso machine (the bypass valve on the pump body itself). In addition to this, there is a second bypass with a needle valve and a solenoid valve on it. This one can be opened as an "intermediate" pressure. You can set it from anywhere between line pressure and pump pressure, though I am not sure how close to line pressure you can come with the pump on, even with the valve wide open.

Anyway, the control does get a little confusing because they left the paddle on the Synesso as a 3-position control (off-line/bypass-pump, from R to L) rather than going to a 4-position. This is slightly annoying, because in manual mode the middle position is line pressure ONLY until you enter the pump position. After you've entered the pump position, returning to the middle position becomes the bypass (rather than line) position. This is slightly convoluted IMO, but in practice isn't terribly limiting, with one exception: It is kind of nice to be able to enter bypass mode after line-pressure preinfusion as a very short (say, 1-2s) intermediate between line and pump pressure. This smooths out the pressure ramp-up a lot and seems to make the system a little more forgiving. If you want to make the machine act like this, you have to program it on the remote. It's trivially easy, but you lose the manual control over preinfusion time when you do this.

I've had the opportunity to mess with the Strada EP a little, and pulled a shot or two from the MP which struck me as not much better than a paddle Marzocco in terms of usefulness. I've also been using my own EP-like mod for my GS3 on a daily basis for some time now and pulled and tasted many shots on the new Synesso. At this point if I had to pick the most usable one, I think it'd be a very decided nod at the Synesso. It's just so much more repeatable and so much easier to use than anything else. The Strada EP I found extremely difficult to work in manual mode—even less usable than my own setup at home. The throttle is just too short for such a wide range of pressures, and the digital output I found much more tedious to read than a gauge. It might be great in programmed mode (i.e. on replay) in a shop, but I thought it was just horrible for toying around. The Synesso also has an easy nod in having its profiling system being very mechanically simple and easy to service (I've actually done a little bit of servicing on my friend's 1-group, so that's very much a firsthand comment). Sorry if that's terribly off-topic.
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Postby Marshall on Tue Aug 09, 2011 5:39 pm

shadowfax wrote:At this point if I had to pick the most usable one, I think it'd be a very decided nod at the Synesso. It's just so much more repeatable and so much easier to use than anything else. The Strada EP I found extremely difficult to work in manual mode—even less usable than my own setup at home. The throttle is just too short for such a wide range of pressures, and the digital output I found much more tedious to read than a gauge. It might be great in programmed mode (i.e. on replay) in a shop, but I thought it was just horrible for toying around. Emphasis added

My observation, from Synesso's to Greg Scace's custom LM controller in Venice, is that most of even the best baristas won't pressure profile unless it's fast, easy and repeatable. They just use the paddles as on-off switches, especially when things get busy. So, I think it would be smart for LM to bet on programmed repeatability, even if that relegates manual mode to a secondary feature.
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Postby napierzaza on Wed Aug 10, 2011 7:06 am

How do you have 1 pump and 3 heads that all have their own variable pressure profile?
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Postby Richard on Wed Aug 10, 2011 9:26 am

In the case of the Synesso Hydra, according to their webpage, each group has an independent pump.
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