Am enjoying Onyx Geometry on my Londinium '17 L1, with Ceado E37s SSP. But I have to use a few crutches to get the shots I want, and am unsure of the best way to improve technique. I recognize the R24's pre infusion would solve my question, but the L1 is what I've got.

• 1:2.5 ratio is what Onyx recommends, and so far is what I like, too.
• High flow, reliable basket. Have others, but suspect this is the right one here.
• 15.5g in, 38g out is target
• Grinding much coarser loses texture and deeper flavors, and the lemon becomes harsh rather than sweet.
• I do use a top sintered screen. Skipping it does not have much or any effect, except that I'll need to clean the group more.
• I am due to replace piston seals, though suspect that's not really the issue. Is it?

1. Grinding as fine as I like for taste and texture results in a very long pre infusion (20s+ lever down before portafilter is evenly beaded). I start the brew at the top of the PSTAT, currently just over 1.3.
a) AFAIK the thermosyphon is prone to stalling after about 10s
b) Taste is good, but I'm wondering if a shorter PI would give more clarity, especially for the promised Earl Grey, etc.

2. Am trying several methods of retarding the lever and Fellini maneuvers to get sufficient shot volume.
a) Lever down for 15-ish secs, plus holding it until first drop at 20° or catch point can stretch to over a minute, and even with a Fellini, may yield 28-30g shots.
b) One or even two Fellinis are needed to get more than 30g out.
c) Best shots come from 15s+ lever down, hold at catch point, Fellini, let it run, then as it gets close to the end of lever travel, I tug it just enough to add a few grams of output--not a whole Fellini, just a little pull.

My best shots are good, yet I can tell where they could improve, and worry that I'm doing too many weird things with my lever to get it to work. What would be more elegant, accurate methods?

I'm very interested in those 'special' lever moves as I have the same machine and am all in with 5# of my first light roast in the freezer. I haven't used a light roast in this machine in about 2 years.

I can only get a 1:2 ratio with a low dose ~14 grams in, (Medium roast). Everything else is absorbed into the puck and honestly the stream blonds just before the lever returns up so I can't imagine a higher ratio.

I'm taking a pint jar out of the freezer to see what I come up with tomorrow, if that helps?

MS

Too much moves are relative, I think. On my Strega I use a 15g basket with no screens and if the roast is less than a week old and light I find grinding a 15g dose on 4 notches or so finer on my Ceado E37J keeps the shots restricted enough from going turbo.

I went back to roasting my own and the beans I'm using on an older Hottop must be more than a year past expiry date. I don't know what the moisture content is, how the roast profile drying is being affected and what, besides something from stale green beans, the character of the roast is going to be when I roast them light. So many variables

The Strega has a pump you can engage for preinfusion which helps really light roasts get saturated and extracted at a high pressure start. That works for extra extraction and volume. If I didn't have the pump my objective would be to fill the grouphead as much as possible, say hold for 20sec or more, gently and slowly let the lever up until the point extraction begins, pull it down again and hold until fill volume and preinfusion catches up to the drips of extraction then let the lever go so the fully compressed spring(s) can do their thing. All that time risks over extraction so I might pull at a start temp of more 80C to 90C.

Other option would be not do a Fellini(s), find a grind setting that starts the infusion when you hold at preinfusion in a time from 20sec to however long works to bring out what you like with the roast, play with brew temperatures for flavour and let the lever lift with varying pressure control from a lot of restriction to a little. I do that with the Strega when I'm using an odd behaving light home roast less than 5days rest to find what works best. Sometimes those roasts need to rest more than 7days and don't seem to settle down and act normal crema volume and extraction rate wise for two weeks.

Mat-O-Matic wrote:Taste is good, but I'm wondering if a shorter PI would give more clarity

Try it.

espressotime wrote:Not extremely souer. Even a lttle sweetness.

Thats not enough, I would say...

I agree with Craig regarding no "screen". That's a heat sink that will drop your temperature about 2° C, you don't want that on a light roast.