samuellaw178 wrote:Can't stand the suspense and warmed up the lever anyway. Tried it and it worked. Sort of anyway, as I don't feel it's repeatable/controllable enough. The brew pressure is in the dark and the spring/line pressure are causing a disconnection between the tactile feedback and actual pressure.

Thanks for sharing.
That's what I found, consistency wasn't great.

samuellaw178 wrote: But I did manage to pull a shot that would've choked (10 notches finer). To confirm, it did choke using the standard 10 sec preinfusion and release method.

The Mythos was gone last week. The HG-1 gets the love mostly and the Mythos was just gathering dust (only because it's not that suited for single dosing)

I didn't have that much latitude in grind settings with my grinders. But the M3 and EK43 have smaller windows for getting a good flow rate.

No worries re Mythos. Was just curious how it would of faired taste wise.

okmed wrote:Wouldn't the thermostatically controlled heaters in the group head on the Strega prevent the water temperature from cooling?

I believe the Strega group temp idle around 80˙C, so the water will still cool.

JohnB. wrote:That's how it works on the Speedster/Spirit. Kees moved the .6mm jet from the group into the hx to brew boiler feed pipe at the rear of the machine to slow the ramp to pressure. When you engage the manual PI it takes a full 12 seconds for the pressure to build to 3 bar at the puck. Initial wetting of the puck is at almost zero pressure and it slowly increases as the pipe & PI chamber fill with water after the jet.

Very cool. Kees is very smart that way.

I know he changed up the jetting (and moved to a single at the back), but I didn't know ramp time (with line level PI) was a full 12 seconds. That's fantastic.

I wish Kees and Jason would share tech. There many functional aspects of the Speedster which I like/prefer.

dominico wrote:If the theory of why you can grind so fine on a Slayer is simply that the puck is slowly wet at hot water at "gravity pressure" (like an EspressoForge) then I suppose you could prewet the puck with kettle water or hot water spout water right before lock in and achieve the same effect.

Prewetting is part of the reason, but pressure ramp up is also equally crucial.

By the way, I've tried the 2 stage pressure preinfusion as suggested (2.7 - 4 bar - 8 bar and declining). With the current coffee I have, it did something really funny. At first I thought the shot was extremely creamy/silky, but it was the result of the shot being 'drier' (mouthfeel) that it tricked my palate. So in a way, it increases the 'perceived body' but not the actual body. Not sure if it makes sense to anyone. The mouthfeel also reminded me of E61 shot (not exactly similar but close). I'll have to confirm that but these are first impressions.

Sweetness seems to be improved but not sure if it's a direct result of this technique. The mouthfeel difference is due to the double stage preinfusion because I got the same feeling from the shots yesterday and today (but not observed in the standard pressure profile).

nickw wrote:I'm curious what lever groups have a need valve integrated into the design?

The FAEMA Zodiaco group has a valve under the group to adjust the flow rate. I tuned it from 20 ml to 4.5 ml a second on my Lambro today. It could be less than 4.5 ml/sec but I do not think it makes sense on a lever machine because it will take too much time for filling the group. If the group capacity is 60 ml, with 1.5 ml/sec flow rate will take 40 seconds to fill.

I used to pre-infuse for 10 seconds with the 20 ml/sec flow rate and pstat set at 0.9-1.1 bar. Today I waited till the appearance of coffee beads under the filter basket with the 4.5 ml/sec flow rate, should be more than 30 seconds, but after lifting the lever with the same method, about 3 seconds to it was caught, I could not see obvious difference of the extraction flow rate than before. The coffee was illy Monoarabica Brazil.

I applied a new technique brought to light in this thread by Nick where I, on my LI, grind finer, pull the lever down just to the point the water enters the group and coupled with longer pre-infusion time, the results after 2 mornings of using this method have been wonderful and noticeable.

It stands to reason the air column above the water inlet effects pre-infusion but I had no idea until I tried this technique the difference in the cup would be so profound. The flavor has more depth, seems to be smoother with, although I will withhold final judgement after I can use the same method on beans I regularly pull but out of right now, more woody/chocolate notes. And I have brought a level of in the cup flavor consistency I've been searching for!

Fun to have a new tool in the tool box!

This is a very good thread!

bakafish wrote:The FAEMA Zodiaco group has a valve under the group to adjust the flow rate. I tuned it from 20 ml to 4.5 ml a second on my Lambro today. It could be less than 4.5 ml/sec but I do not think it makes sense on a lever machine because it will take too much time for filling the group. If the group capacity is 60 ml, with 1.5 ml/sec flow rate will take 40 seconds to fill.

I used to pre-infuse for 10 seconds with the 20 ml/sec flow rate and pstat set at 0.9-1.1 bar. Today I waited till the appearance of coffee beads under the filter basket with the 4.5 ml/sec flow rate, should be more than 30 seconds, but after lifting the lever with the same method, about 3 seconds to it was caught, I could not see obvious difference of the extraction flow rate than before. The coffee was illy Monoarabica Brazil.

I have the exact same group, how are you measuring the flow rate? and roughly how many "turns" from fully closed is that?

bakafish wrote:The FAEMA Zodiaco group has a valve under the group to adjust the flow rate. I tuned it from 20 ml to 4.5 ml a second on my Lambro today. It could be less than 4.5 ml/sec but I do not think it makes sense on a lever machine because it will take too much time for filling the group. If the group capacity is 60 ml, with 1.5 ml/sec flow rate will take 40 seconds to fill.

I used to pre-infuse for 10 seconds with the 20 ml/sec flow rate and pstat set at 0.9-1.1 bar. Today I waited till the appearance of coffee beads under the filter basket with the 4.5 ml/sec flow rate, should be more than 30 seconds, but after lifting the lever with the same method, about 3 seconds to it was caught, I could not see obvious difference of the extraction flow rate than before. The coffee was illy Monoarabica Brazil.

Cool you can play with the valve.

I noticed with boiler level PI there wasn't much difference, but it may also be grinder dependant.

You may also like getting some freshly roasted coffee. I find nitrogen flushed coffee (like Illy) does okay for the first day or so, then drops off fast.

spressomon wrote:I applied a new technique brought to light in this thread by Nick where I, on my LI, grind finer, pull the lever down just to the point the water enters the group and coupled with longer pre-infusion time, the results after 2 mornings of using this method have been wonderful and noticeable.

It stands to reason the air column above the water inlet effects pre-infusion but I had no idea until I tried this technique the difference in the cup would be so profound. The flavor has more depth, seems to be smoother with, although I will withhold final judgement after I can use the same method on beans I regularly pull but out of right now, more woody/chocolate notes. And I have brought a level of in the cup flavor consistency I've been searching for!

Glad I could help, and thanks for sharing.

With slowly wetting/pre-infusing the coffee (by pulling the lever to where water would slowly come out) in the end, with lots of comparison, I didn't find that big of difference. I'll elaborate a little more. Based on your results, I suspect the results could be grinder dependant.
- With the EK43, it likes a more straight shot (little to no PI approach).
- With the aligned M3 there was some difference, but not enough to warrant it. I suspect with line level pressures (rather than boiler) I could of gone finer.

Just speculating now:
With your conical, it's sounds like it's making a difference, and allowing you to go finer? Logically, I thought it would give me a difference, but it failed to materialize for me, but perhaps it is for you, based on your grinder. As conicals tend to have a bigger window for a good flow rate (because of a wider distribution). Metaphorically speaking, perhaps it's allowing you to tighten the grind some, which in effect closes the window, and gives you better results within in. But I'm just thinking out loud now.

Side note:
I also found, that pulling the lever to just before the point where water came out, as I said in post #19 made a nice, easy, and consistent difference. Especially with the VST.

After pulling the lever to the point where just the water comes out, do you then continue all the way down, or when you hear that the chamber is filled do you go back up from that point?


I think I may want to incorporate some of your guys' cool techniques into the initial post.