Hello, Gang!

So let's have a talk about the venerable La Marzocco Linea EE (that's the one with the auto buttons, I believe) and everybody's third-favorite dicussion topic: Pre-Infusion!

There is (has been?) some talk about using different sized gigleurs (link) to reduce the flow rate to the grouphead in order to physically force the LM grouphead into a sort of soft infusion and slower ramp-up to full pressure.(http://coffeegeek.com/forums/espresso/machinemods/439567)

There is also some chat (http://coffeegeek.com/forums/espresso/machines/419375) about the use of gigleurs vs. the use of paddle-based grouphead design.

But, is it not the case that with Linea EEs, you can program in a pre-infusion? The question is mostly rhetorical, as I know that you can, and I have, and it works, at least insofar as it engages the pump momentarily, pauses, and then applies the remaining pre-programmed shot volume. However, the swirly-infinite button and semi-auto toggle DO NOT then utilize the programmed pre-infusion. 

So, how do we mod our grouphead, gang? Do we install gigleurs so that our more experienced baristi using the semi-auto toggle get the same pre-infusion (or at least SOME kind of pre-infusion) as our rookie baristi who are still using the volumetric controls? It would seem that a Linea EE programmed to pre-infuse and fitted with a gigleur is going to manifest its pre-infusion in a pretty soft way, and might be worth trying out.

I am not convinced that pre-infusion is the way to go at our shops, but it seems that there are a number of options here (not including paddle installation)

1.) Leave the machine as is, programmed without pre-infusion
2.) Program machine to use pre-infusion on the volumetric buttons
3.) Install gigleur to reduce flow rate and create a slower pressure ramp
4.) Program for pre-infusion AND add gigleurs

Any thoughts?

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EE is semi auto. AV has volumetric dosing.

also, wrong forum. yet again.
Do you notice an improvement in flavor from the pulse "preinfusion"? Why not program one to dispense lots of water and you can use it just like the swirly button?

I'd add another option - add a "pump off" switch to keep the pump from kicking on when you start to brew. Same basic effect as the paddle, but cheaper and easier.

I happen to like the "slow ramp-up" approach better, that may be the way to go. I've not done this, and have heard two differing views:
1. It can be done and is good, here's how.
2. You need to totally redo the plumbing, something about banjo tubes.

Not familiar enough with the plumbing on Lineas to speak too much to this, but thought that link might help.
JR: You're right! It's an AV - my fault for not checking before posting. I've also moved it to the 'Equipment' forum, hopefully that will drum up some interest.

B: I'm not totally sure that the differences I noticed are from actual improvements or psychological preference - I'm a curious tinkerer by nature, so I often like to believe things sometimes are better than they actually are. I'm planning to do some kind of blind taste-test soon.

I'm not certain yet, but if I follow through on this, Option 1 is I think the way I'm going to go: Troy is talking about the same gigleurs that I am thinking of getting, and it seems to me that if I decide to go with a pre-infusion, a combination of .6mm gigleurs and the programmed preinfusion would be the way to go, as it would allow for a slower advance of pressure, as opposed to the sort of "heavy pressure, delay, heavy pressure" option. Here's why:

We have three possible setups:

GIGLEURS ONLY: Pressure is applied constantly once pump is engaged, though the ramp-up to 9 bar is slower than the stock plumbing - should only affect pressure for the first 5-7 seconds. More of a pressure profile than a "true" pre-infusion

PROGRAM ONLY: Pressure (appears to be) applied as usual for ~1 second (which I would imagine is well south of 9 bar, though the gauge reads just shy of 9 - no way the Linea goes from no pressure to full pressure in less than a second, right?), delays ~1 second, then ramps up to full pressure immediately. This is a pre-infusion, but it's not obvious that a full-pressure pre-infusion is going to make much of a difference, as it will still do the damage to the puck (turbulence, channel creation, etc) that a normal infusion would, just earlier.

GIGLEURS AND PROGRAM: This seems to be the way to go, in my mind - this way that programmed pre-infusion is at a much lower pressure, thanks to the restriction provided by the gigleur, still has a delay to allow for expansion and so-called 'sealing off,' but won't blast away at the puck the way the full-pressure pre-infusion would.

Am I on the ball here or have I missed something?
So I have a question that is likely coming from my ignorance. Is pulsing the semi auto toggle an effective way to pre-infuse or is this counter productive since the pump is either on or off?
Dave Crumbo said:
So I have a question that is likely coming from my ignorance. Is pulsing the semi auto toggle an effective way to pre-infuse or is this counter productive since the pump is either on or off?

I'm curious about this as well. Anybody done side-by-side blind tastings with this?
When I think about getting involved in a multi-branching set of possibilities and trying to figure out the "best way out", it is easy for me to want to work in a backwards sort of way. I am suggesting that if you thinking there is a significantly better cup of coffee by making lots of mods to your machine, and utilizing complicated preparation routines, then you are working backwards. If it is that important to you, and you were dedicated to achieving this superior cup of coffee, you would already own a soft infusion machine with extremely small aperture Gicleurs.

If you think about taking the path of least modification and using the most efficient preparation routine that involves the least mental processes to get the results you want, then you are thinking forwards. As Brady suggested, program the electronic pre-infusion with an almost unlimited shot volume on all buttons. Employ the buttons as semi-auto buttons. Never use the swirl button or by-pass button. You will have pre-infusion on all shots without any changes to the machine and the ability to monitor shot volume and timing yourself.

On a related tangent, I was using an EE Linea just the other week with no pre-infusion of any kind. Coupled with a brand new grinder and fresh coffee, I was getting spectacular tasting espresso. Actually, they were the best shots I have had in the last couple of months. The other day I was using an FB-80 with tight Gicleurs that deliver very slow infusion. The coffee was again fresh, but the grinder burrs were past their prime. The shots were very unpleasant, no matter what the dose, shot volume, flow rate, or grinder setting. Fresh burrs cure that in an instant. So really, I would not dwell on the quality difference between soft infusion vs. pre-infusion vs. hard infusion all that much. Make sure everything is in a state of proper maintenance and use fresh (or properly aged) coffee. It is so much easier when you only have to worry about grind setting and appropriate does and shot volume.

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