[Rob1]

AFAIK the LMLM isn't anything special. Saturated group. The paddle isn't functional for flow profiling I don't think, not without modification anyway unless they've changed it.

 

[Rob1]

@DavecUK

The magazine mentions 2 machines - the Vostok and the Vesuvius Leva. The former is dual boiler and the later is s single boiler. Are these two are now rolled into one as a dual boiler? Thx

The latter isn't described a single boiler. It is described as being the same as to Vostok but with a 3 litre tank. A tank is a reservoir.

 

[Rob1]

Then grind to brew in 40-ish seconds? I see you're trying to match the numbers from other people....if you're using the same grinder and the same coffee then you should get close, otherwise I wouldn't expect to be able to get things the same.

 

[Rob1]

You are missing the point, I'm not trying to match anyone, I want to keep my current preferred recipe brewing at 10.5 bar but with longer preinfusion at lower pressure. The main design criteria for the machine was to have two springs in the group so that higher brewing pressure could be achieved, but mine doesn't do that unless I keep the PI pressure high as well.

I'm really not. Whether you're trying to match somebody else's numbers or numbers you just want to hit, you can't force a coffee to behave in a specific way. It's not the machine, it's the coffee (or possibly the grinder). Low pressure starts make pucks less resistant to pressure later on (which is why you aren't hitting max pressure). You might be able to achieve a low pressure pre-infusion and a 10.5 bar shot at suitable flow rate to deliver a 2:1 ratio in 30 seconds withe one coffee and grinder/grind setting but not be able to do it with another. If you've been able to achieve this on another machine, are the basket diameter and puck depth the same?

Regardless, if you want to hit your max pressure with extended pre-infusion you'll need to either grind finer or dose more.

 

[Rob1]

It would be interesting to these those shots repeated with a puck screen in place.. and also to compare various showerscreens!

Most of the expansion occurs when the shot finishes and pressure is released. If you spend a very long time wetting the puck without pressure build up logically the puck could expand more before it comes under pressure There is a little device I've seen that prevents or limits the puck expansion. It was like one of the puck screens but with a height adjustable top part that would screw up and down and sit against the shower screen.

 

[Rob1]

Hmm don't you think it's a problem that parts of clip covered some of the shower holes?

why?