I've had a few requests for videos of my machine in action aside from my "silent shot" videos, so here are a few of my first narrated videos taking you through a variable flush and then a profiled shot: Variable "Cooling" flush from 8g/s down to zero and back up to 1.5g/s
Profiled shot starting at 1.5g/s, taken to full flow and then progressively profiled back to 1g/s

In case you haven't noticed, I'm SLOW at making changes. I have all my plans in place to get my Sprofiling knob poking out the front of the machine, but there's no hurry just yet. Plans include a 4PDT relay that will replace my current brew switch. As noted previously, the open side of my double gang pump kill switch will control the coil of the relay. 2 NO poles of the relay will switch the solenoid and send power to the pump kill switch, replacing the brew switch. 1 NC pole will interrupt the boiler fill solenoid when brewing. I've had about enough of that. I'll have an unused pole to do whatever with should I decide I need it, but I think that will be enough for now. Once the switch is out of the way, then it's on to finding a suitable flex-shaft to extend the needle valve out the front. 8X6 tubing is likely the best bet right now, but once I've got an opening I'll put more thought into the best, cheapest and most simple solution. Remember now, this is a $200 machine, so yes, my S/D ratio is quite high!

Cheers!

- Jake

Jake_G wrote: NC pole will interrupt the boiler fill solenoid when brewing. I've had about enough of that. - Jake

LOL got a chuckle out of this comment; Yea nothing like getting a "Water Call" when profiling a shot!

Every machine should have this feature.

I've posted a strip down and dimensional details of the Bianca metering valve over on the Lelit Bianca user thread. Array/espresso-machines/lelit-bianca-user-experience-t54490-50.html#p616594.
While you don't need this, Jake, from the assembly viewpoint, lifetime design, cleanliness and maintainability may be interesting...

Received my first ever order of mail order coffee yesterday:

If nothing else, it's good to try different things, right?

Hopped up on Indian Robusta at the moment. Had a cap and 2 straight shots finding the sweet spot. I really like being able to emulate the ramp up of different machines by adjusting the water debit in the fly. Following in the footsteps of Decent and what Jim has found with Bianca, 4ml/s seems a very good water debit to get a typical E61 ramp up. Here's shot of 18g in, 21g out in ~36s. Going to slow the flow a bit more tomorrow with a tighter grind and see how the flavors change. As posted earlier in this thread and in the ongoing discussion, Looking for a Simple Measure of Preinfusion, I think that there is a benefit to matching the water debit to the permeability of the puck and the available headspace such that pressure builds only after the puck is saturated. That said, I'm looking forward to doing some testing to try and see what happens as we shift the absolute timing of these events, but keep their relationship to each other relatively constant. Basically, I'll adjust grind to lengthen the shot duration and then adjust water debit to ensure that pressure comes after saturation, which should then shorten the "extraction" portion of the shot.
Unfortunately, I'm learning as I write this that 3 shots of Malabar Gold is quite possibly 2 too many...

Holy smokes, this is different than a Brazilian SO!

Cheers!

- Jake

Jake_G wrote: I think that there is a benefit to matching the water debit to the permeability of the puck and the available headspace such that pressure builds only after the puck is saturated.

I had just posted a shot profile I hoped would be useful, over on the Bianca User experience thread, when I dropped in here and read your comment, Jake. It seems I've just made the same point, in a different way.
My posted shot profile was a "dialling in" tool, aimed to give an outpost in the Bianca wilderness. But there's still that danger of consuming quite a few shots while finding the sweet spot on a new roast, then having to come down from the caffeine induced plateau!

I've been following this superb thread for some time and have had a go at replicating a few shots on my GS/3 MP. While I can control pressure and flow on the fly, I don't have any measure of flow rate.
I've heard that the Acaia brew master app can display real time flow rate on a bar graph but was wondering if that's what you're using or if there's an app/scale that displays it digitally in grams/second?
Any tips are appreciated.
Thanks.

another_jim wrote:I guess I'm not familiar with the selection. The ones I tried required lots of turns.

True. Most do. But not all. You just have to look a little harder. And of course, the less arc to turn between full closed and full open, the bigger change in flow per degree in movement. My "first cut" at needle valving my machine has a needle valve with 180 degrees of movement, where most of the flow comes in the first 90 degrees from full closed. I wouldn't want it any more sensitive than that, but as is, it's still very workable, and easy to get as low a water debit as you like to start the shot. For my "second cut", I'm going to try Jake's valve. Since my machine, (and I think Jake's as well) do not have separate paths for "pre brew" and brew (like Slayer), I want a valve that does not take too much arc to go to full flow. So the common micrometric adjusting valves I think you are talking about, the ones that take a lot of turns, are not convenient for me.

-Peter

Yeah, this stuff is new to me. Andy Schechter tried a micrometric needle valve on his Frankensilvia, then switched over to a gear pump. If he had known about the easy turning, 90 degree jobs like on the Bianca or Jake uses, the whole gear pump in espresso machines thing may have been a might have been.

I've been wondering about the positioning of the flow/pressure control. On the Bianca, it's right above the puck; on machines like the Hydra, Mina or R 9 One, it's a gear pump at the very beginning of the brew path. The Slayer and Jake's machine have needle valves on the cold water side of the boiler. Does having it closer to the puck make it easier to use, or is the lag time introduced by of having it closer to the pump a non-issue?

another_jim wrote:I've been wondering about the positioning of the flow/pressure control. On the Bianca, it's right above the puck; on machines like the Hydra, Mina or R 9 One, it's a gear pump at the very beginning of the brew path. The Slayer and Jake's machine have needle valves on the cold water side of the boiler. Does having it closer to the puck make it easier to use, or is the lag time introduced by of having it closer to the pump a non-issue?

So water is incompressible. So given a rigid set of pipes and assuming all air bubbles are properly bled out - it should make no difference.

However, water does expand a bit as it heats. So assuming cold water enters the boiler - a few drops of expansion will be pushed to the group (like for the expansion valve). But that is minimal.

So with a flick of the paddle (my contol is on the hot water between the HX tube and the coffee water boiler), a drop can be left hanging, or pressure varied instantaneously.

While I cannot definitively claim it cannot be improved upon - I am not feeling any lag whatsoever and hence not on the lookout for a better solution.

another_jim wrote:Yeah, this stuff is new to me. Andy Schechter tried a micrometric needle valve on his Frankensilvia, then switched over to a gear pump. If he had known about the easy turning, 90 degree jobs like on the Bianca or Jake uses, the whole gear pump in espresso machines thing may have been a might have been.

Gear pumps have unique advantages of their own. They vary the water debit available to the machine (not just the puck). As such, any channel gets rewarded by an almost instantaneous drop in pressure (think voltage in a constant current setup), which seals the puck again. It is very easy to pull with a gear pump.