bringyoutomyhell wrote:Ok it's clearer now.
What I know works for dark roasts is a quick peak at 8 bar and then a constant release of pressure

For light roasts it's better a 20 sec preinfusion, once you saturated the puck, then a 6 bar pull (you get higher extraction with lower pressure due to how the puck "compresses").

And yeah, possibilities are endless

Thanks for providing the Decent link. I'll download it and have a look.
Just one question regarding nomenclature... Why is X "Bar" singular and not plural???
Right now with a blank disk I'm showing pressure of 10 "bar" which I reduced from a 12 bar that came from the factory. I'm told that 9 bar is the gold standard, but set it to 10, for reasons that go unexplained.

I didn't realize that when I went shopping for my "last" espresso machine that I'd be diving down a deep, deep rabbit hole. I do enjoy the minutia, breaking it all down, then coming back to simplify everything. I'm far from there now, but can see I will enjoy the "art". So much to learn.

Yeah, for some reason most (all?) prosumer coffee machines have the OPV valve set too high. No one knows why. My hypotheses is that it helps people with low end grinders and manufacturers have less annoyed customers that way, even if it's worse for the extraction.

About bar/bars that's funny, I have no idea

Update: GETTING CLOSER... to understanding and setting on a setting.

I decided that the best way to approach this was to initially simplify. Decide on which flow to start with and put the paddle in the far right position. I thought that it best to settle on the max flow I wanted and forget about being able to shut off the flow entirely with paddle-left. So the flow settings I have right now are Paddle-left 4.2mL/sec and Paddle-right 6.6mL/sec. I did two pulls this morning, all full paddle right, no infusion.

I decided it was best to find a starting dose (18g La Colombe Nizza) and starting grind, then even it all out (WDT+OCD) then tamp and then pull my shots timed with no pre-infusion or any paddle movement. The first shot was 36 seconds and the bottomless was showing blonding early on. I adjusted the grind on my Sette 270 one click coarser and repeated. Second shot was 25 seconds. The taste was not bad straight out. The bottomless stream looked much better. It tasted good enough to then do some milk steaming. At this point I'll have to consider how I want the taste to be better and then figure out how to do it. Perhaps the next step is add pre-infusion with the E61 handle partially up. How many seconds is recommended for P-I?

A note on the (home-made) WDTs... I have created a few of my own WDT's with Proseco corks and both sewing needles and toothpicks (and one nail). I think the single toothpick is more manageable for declumping where the multiple needles seemed to make more of a pocked-looking mess. The single toothpick left the grinds look more uniform. The single toothpick was chosen to emulate a dissecting needle (as I saw in one video).

Milk: I got pretty close to getting the steaming right. A few too many big bubbles that I think I introduced later on in the steaming and almost got the texture right. I need a lot more practice. Actually I prefer capps to lattes but the draw of what you can do with a latte is intriguing.

So that's today's update for those who have helped me and those later on who might be interested in the journey of a beginner.

There is a lot to get a handle on. In this momentI think it is best to continue with the La Colombe Nizza beans. They get shipped here weekly from Philly and they have to be close to "roast date" as the marked "best by" date is MONTHS closer than those same beans sold in their stores locally. I have to guess 4-5 days off the roaster. They usually sit here for a few days before I finish the last of the previous batch. So what is the best way to store the new beans until I start the new batch? I've been using old Illy cans, but they can't be ideal, but have to be better than the plastic bags the beans arrive in.

Thanks for the insight on WDT tools. I will build a new wdt tool today with a single thin needle. I've got one with several thin needles but I think one needle might give more control.

After getting straight pulls first I'll try the declining extraction method which makes sense for the next step. Repositioning the paddle to test different ranges for it is clumsy. I purchased an audio knob yesterday that fits on the shaft which might be useful for helping to determine the best flow rate with the paddle installed. While the knob itself doesn't provide any smoothness on its own or aesthetics but I can get it to work as a temporary exploration tool as the paddle is less than ideal for discover within the 540 degree rotation of the shaft. HOW COME THERE ISN'T *ANY* INFORMATION ANYWHERE ABOUT THE LIMITATION IN THE PADDLE DESIGN.?? If I had known the paddle's limitations I might have chosen the QuickMill FCD with the full rotation knob Repositioning the paddle for the different ranges is clumsy. and saved $40. How much difference is there between any of them internally? But I have what I have and I will figure out how to work with it.

So far the QM67 itself seems pretty fabulous. I'm glad I went with double boiler. Now I just have to dial in ME! I'll get there and appreciate the help and advice. For my friends and family it all seems like so much work. For me, it's fun.

There is no limitation in the paddle design.
It works perfectly with the machine that it was designed for and on other machines when used within its design parameters.
WTF do you want 7/8/9 ml/sec flow rate for?
You are shooting for about 36-40 ml of out put in 25 seconds!
If you want a massive water debit in the first 2 seconds, buy a big lever machine.

I think you missed the point of my question. I'm not looking to get massive water debit but to discover what is needed; with almost zero information on the subject anywhere. The limited information that is there has to be piece-medaled together to form any useful conclusions.

Your information about 36-40mL/25 sec tells me the obvious; the yield. What I don't know is the recommended milliliters per second of water go again to achieve that yield.

Morning update...
I readjusted the machine this morning. I checked the pressure with the flat disk. A little high but now squarely at 9 bars. I reset the paddle to have zero flow on the left and 5.2mL/sec far right. Got a straight 25 pull from 18g that was pretty good. A bit later my sister came over and I made one for her, this time doing a decline toward the end. Still 25 seconds. She said "It was the best coffee I've had this year". She repeated that several time so I can only assume it was genuine. I don't really know what I'm doing, but I must be doing something right. I'm thinking perhaps I need to grind a hair finer or add 1/2 gram of beans. Or maybe, with these beans I'm good where I am. At this point I think my palate is the weak link in this whole process.

Hi Vincent.
For a fairly standard espresso you want a 1 : 2 ratio of grams in and grams out.
My reference to ml is merely to approximate your output.
The output will be made up from crema(which is lighter than water) and espresso(which is heavier than water as it contains the dissolved coffee solids) so you need to go on weights not volumes.

However, to get 36grams of espresso you will not need more than about 70 grams of water.
Your puck will absorb some water during the process but iirc when I tested it with my machine it was only around 18grams.
Easy experiment, weigh your input dose and then weigh your puck after extraction.
It will lose some solids and gain some water.
Add the weight of your used puck to the weight of your output and you will have the weight of water debit for the shot if no coffee solids were extracted.

So, suppose your dose is 18g, and your used puck then weighs 36g and your output weighs 36g, your maximum possible water debit is 72g over 25 seconds or less than 3g/sec.
In reality it is less than this as you will be extracting solids from the puck.

For a recipe, try this.
I copied this from DaveC and I think it is something like a Slayer shot.

Use your grind and dose that gives you your best 25 second, 1:2 ratio shot with the FC all the way to the right.
Turn off any preset infusion.
Set your Paddle to 4 o'clock.
Start your shot.
After 5 seconds close your paddle, don't close it all the way until your group head gauge reads 2 bar.(always close it gently).
Wait another 15 seconds,( by this time you should have one or two drops in your cup) and then turn your paddle to 3o'clock.( this should give you around 9bar at your group head.
When you have about 20grams in your cup slowly close the paddle to drop the GH pressure to around 6 bar.
Stop when you have reached your 1:2 ratio output. ( eg 18:36)
This can take anything from 40-60 seconds for the whole process.

There are quite a few profiles out there if you search for them.
Good luck.