Epicurus wrote:Yes, it's the same as slapping the paddle on and off, so you could technically do the same thing as the app if you flipped the paddle back and forth a few times. The needle valve mod (Slayer style) does pre-infusion by regulating the flow rate to saturate the puck (though the pump pressure remains the same). The gear pump mod (Strada style) is different in that you can regulate pressure throughout any part of the extraction using the variable speed pump. Flow profiling and pressure profiling are two different things.

For example, the LM GS/3 MP is much more of a flow profiling machine (though kind of a hybrid) since the pump always remain at the same speed, but you control how much flow hits the puck by raising and lowering the conical valve in the group with the paddle.

Is flow not related to pressure? Is there really a difference between flow profiling and pressure profiling? The only difference seems to be which one you choose to control which leaves the other as the affected variable so I'm not sure there's a real difference there, at least in my head it seems that way and I've read a few editorials saying as much. Thoughts anyone?

Also with the LMLM method on-off is there not also a risk of destroying the puck of you let it fill the basket too much and create pressure? Because then when the 3way opens it will release that pressure suddenly

I'm leaning towards the Grafikus needle valve mod but still hold out for info on Rick Bond's version. Curious what the difference would be including price. If anyone has installed his I'd like to hear about it.

Also considering the Grafikus kit purely because it it available to buy vs all the others. I think gear pump is ultimately what I want but I haven't seen that as a kit. I know little about machine internals but I'm fairly confident that with clear instructions and a kit containing everything required, fitting a gear pump wouldn't be beyond the skill level of me or most other people. If anyone knows the list of parts required and took time to create instructions, I think they would have a few customers.

Epicurus wrote:The "pre-infusion" in the app is really more of a pre-brew. It applies the same level of pressure (9 bar) for the programmed pre-brew time, then pauses, and then finally continues for the remainder of your pull. Pre-infusion should apply a much lower level of pressure (~3 bar), or flow rate, to saturate the puck before ramping up to full pressure/flow.

Epicurus wrote:Yes, it's the same as slapping the paddle on and off, so you could technically do the same thing as the app if you flipped the paddle back and forth a few times.

Well that's kind of disappointing! Thanks for the explanation though!

sluflyer06 wrote:Is flow not related to pressure? Is there really a difference between flow profiling and pressure profiling?

I pretty much forgot most of my hydraulic engineering coursework from a long time ago (never thought that would become even remotely useful lol), so I'd refrain to be too definitive here. But my understanding is pressure and flow rate are not really the same thing.

A pump delivers a flow rate (which depends on speed of water x cross section of your tube - i.e. volume of water moved per second), and the pressure is the result of the resistance of the puck (and anything else on route).

I'm not sure of the difference between reguling flow vs. reguling pressure, as my understanding is you can only regulate flow, but control pressure as an output.

My understanding of what Epicurus described as the difference is:
- LMLM app = pump works at full speed for a few seconds, then stops, to wet the puck
- Needle valve mod = pump works full speed, valve regulates pressure after the pump, resulting in ~3bar pressure, then works at full speed
- Gear pump mod = the pump can work in a wide range of speed, allowing various resulting pressures on the puck, to your desire
- GS3/MP = the pump works at full speed, but you can reduce the flow that comes on the puck with a valve that is between the puck and the pump, resulting in the puck pressure you desire at any time

I'm still learning so if anything wrong please help correct!

This raises a new naive question to me which is: why not just regulate the pump speed with a Variable Speed Drive / Variable Frequency Drive? To my knowledge a lot of industrial equipments use that, e.g. for energy effiency and such - seems to be much more simple and flexible to implement than, say, installing a gear pump?

I have the Grafikus needle valve mod installed on my linea mini for a while now. Its availability is what made me pick the linea mini (I bought it last summer), and also why I got mine used (so I won't worry about modifying it and losing the waranty).

Basically it adds a second switch on the brew paddle, and a 2 ways solenoid walve in the hydraulic circuit. You'll then have true preinfusion when the paddle is in the middle position (the needle valve can be adjusted with the cover open, I've set mine up to about 2,5 grams/sec), and full flow at the left position of the brew.

For me this is perfect since I'm drinking light roasts, and after installing the mod I'm able to pull very balanced espressos using filter roasts (with a good grinder).

"Hi there, this is a quick note to let you know that we're updating our espresso machine prices. Starting February 1, 2022, La Marzocco Home prices in the United States will be updated to:

Linea Mini: $5,900
GS3 AV: $7,500
GS3 MP: $7,900

If you've been looking to upgrade, there's never been a better time to lock in your order. Linea Minis & GS3 lead times are currently 8-10 weeks."

Wowsa

The Linea Mini is still a very desirable machine, but I'd worry about LA Marzocco losing marketshare to competitors. The Eagle One Prima and recent Elektra machines look like strong competition.

The Prima was on my upgrade list originally, but it seems to be super buggy according to the Eagle thread. The SanRemo was on my consideration list, but the small steam boiler and list price took it off.

There was already a news message on La Marzocco having the best financial year in 2021 with a 60% increase over 2020, which was their previous best year. They were able to hire 90 new employees in 2020 and 120 more in 2021. Most has been due to the popular demand in the home consumer market, i.e. Linea Mini's and GS3's.

Source: https://www.comunicaffe.com/a-golden-ye ... 0-million/

My machine left the factory nov '21 and has a serial number in the 342XX range (serial numbering appears to start at 0 and each machine is a +1). This article writes that over 15.000 home machines have been produced in 2021, so it's pretty safe to assume the LMLM and GS3 are having their best sales numbers ever.

So yeah, business is good at LM and all credits are due to them. The new price increases are intimidating (my machine was significantly cheaper), but for what I paid I don't believe they weren't grossly overpriced and I won't say no to a higher resale value. Almost 1-month in and I'm very happy with my purchase.

Arafel wrote:The Prima was on my upgrade list originally, but it seems to be super buggy according to the Eagle thread. The SanRemo was on my consideration list, but the small steam boiler and list price took it off.

I've had my Prima for over six months now with none of the "bugs" that the earlier machines had... works well (& looks great).