Lelit Bianca User Experience - Page 29

Need help with equipment usage or want to share your latest discovery?
thm655321

Postby thm655321 » Mar 14, 2019, 10:38 pm

If you do a long say 2 bar preinfusion though then the puck will finish much wetter I find.

wesleynance

Postby wesleynance » replying to thm655321 » Mar 15, 2019, 9:15 am

How long? I preinfuse at 2 bar for probably 10 sec or so, until there are some drips in the cup, and my pucks pretty much look like that most of the time. Using a distribution tool helped tremendously with even extraction and less channeling.

Also, since grind on the Bianca can be all over the place and still have successful extractions, it's possible that our grinds are quite different, and I'll bet different baskets matter as well. I use a VST 18g.

pcrussell50

Postby pcrussell50 » Mar 15, 2019, 4:06 pm

Anyone have his Bianca that is plumbed to mains pressure?

Because I see the possibility for some complex interactions. Line pressure pre infusion... you can slow it down with the needle to whatever you want, I assume? But then when you turn on the pump and it wants to shoot up to (say) ten bar, do you stand at the ready on the paddle to cut back the flow to what you want?

Reason I ask is that I am thinking of doing a mains plumbed rotary on my needle valved machine. It's needle valve is like Bianca in that the whole extraction goes through the needle, and I have on-the-fly control of it. not dual pathways like Slayer.

In short, describe to me the how you do a long pre infusion shot on a Bianca plumbed to mains pressure.

-Peter
LMWDP #553

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another_jim
Team HB

Postby another_jim » Mar 15, 2019, 6:20 pm

I don't see how it would matter. I can reduce the pressure to zero with the pump running. If I had the my Bianca plumbed; I'd be able to lift the levett halfway and get line pressure, and needle valve control that from say 3 bar, or whatever the limee pressure is, down to zero. If you turn the pump on, it would be the same as with the tank model.

Even without a needle valve, a plumbed E61, or any other plumbed machine with the proper switch installed, can do a long line pressure preinfusion for as you please. That may capture a good proportion of the profiling benefit, since it would permit super fine grind shots.
Jim Schulman

pcrussell50

Postby pcrussell50 » Mar 15, 2019, 6:26 pm

I was wondering if switching the pump on after pre infusion would cause an unwanted pressure pulse that you would have to react to quickly with the paddle.

Right now on my vibe pumped needle valve machine I just turn on the pump and use the "paddle" (it's a big knob on mine), from start to finish. There is no pressure pulse partway through, from turning on the pump. And I was wondering how much of an issue that pulse was.

-Peter
LMWDP #553

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another_jim
Team HB

Postby another_jim » Mar 15, 2019, 8:17 pm

There is no pulse; the flow from 1/4 second from the lever opening the valve to starting the pump is absorbed in the group's preinfusion chamber and headspace.
Jim Schulman

pcrussell50

Postby pcrussell50 » replying to another_jim » Mar 15, 2019, 10:14 pm

Might be a e61 characteristic I wasn't aware of... Still, wouldn't the headspace and PI chamber already be filled during the line pressure pre infusion, before you switch the pump on?

-Peter
LMWDP #553

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another_jim
Team HB

Postby another_jim » Mar 15, 2019, 10:43 pm

Ah, now I I finally get it! You want to preinfuse at line pressure for a while, then turn on the pump and use the needle valve. It's a little bit over the top, but yes, if the needle valveis opne, the pressure woild max out in about 1/2 second (I'm guessing this based on oressure recordings of E61s with rotary and vibe pumps -- they both take about 8 seconds to fill up, then the ramp up is a lot faster with a rotary).

I suspect there's a lot of different ways to get around this problem.
Jim Schulman

pcrussell50

Postby pcrussell50 » Mar 15, 2019, 11:23 pm

Now we're playing off the same sheet of music :) Thanks, Jim. So maybe not even play with LPPI? Just run the whole shot with the pump on adjusting needle position as desired.

Thinking about LPPI appears to be a lasting relic in my psyche.

-Peter
LMWDP #553

nodrac

Postby nodrac » Mar 16, 2019, 7:26 am

Yesterday i purchased lelit bianca. Seller said me bianca engineer designed new paddle valve and show me the pdf file and unlisted youtube video. Do you know this?

reference part number of the kit is 1000185