Nurri Leva S. A. - Page 20

#191: Post by **jontyc** » January 26th, 2023, 8:50 pm

Happens quite frequently, because I'm also using tea tap to heat cup and jiggle emptied PF back in place to splash some water up into the grouphead to clean it. Did you used to hear the click of death with your Pompeii?

January 26th, 2023, 9:12 pm

Not that i can recall during an extraction though i was not looking out for that sound then. I never used the water tap to heat cups as i put my cups on top of tje machine and i only made 2 cups in the morning anyway so it was hardly a workoiut for the machine.

#193: Post by **bakafish** » January 27th, 2023, 2:00 am

Viernes wrote:The Bianca is an excellent machine, and you get better results. So it's pretty confusing for me. Sorry.

So what you want is constant pressure but don't want to reduce the flow rate with another tip?

I'm afraid this is not possible and it goes against physics. IMO to achieve that, it's necessary to reduce the tip hole diameter to get less flow rate and sustained steam.

Machines used in coffeeshops may achieve this, but how much water (boiler size) do you have to heat to get this? I had a GS3, great steaming power, but every time I wanted a cappa I had to warm up the 3.5L steaming boiler. Frankly, I would rather never have to do this at home again.

I understand you want high flow rate sustained steam to get milk quality like coffeeshops. IMO, this won't give you by itself what you're looking for. Foam quality relies heavily on the technique to introduce air and vortex forming, and how much water is introduced into the milk.

With too much power, most users are going to get difficulties to froth right a little jug. As you have seen, this is not an issue with the current L-Type configuration. Works well for littles too. If you can't control the vortex, you will get poor foam, for sure.

Lelit Bianca has 1.5L steam boiler with 1400W heating element and a dedicated PID for the steam boiler, so it has the constant steam pressure when steam milk. The inner tube diameter is smaller, the copper pipe between the steam boiler and the steam wand as well, so its steam flow rate is lower. I took out the inner tube of my Lelit Bianca and replaced the steam tip with the Vortex 3 hole steam tip, https://baristawarehouse.com.au/product ... -steam-tip. The steam flow rate was increased and it still had constant pressure.

IMO, the Nurri Leva's steam pressure drops quickly due to the design. If it uses a higher wattage heating element and a dedicated PID for the steam boiler, even it cannot have constant steam pressure, at least it would never drop so quickly, and it will not increase too much cost.

I had said, the key to make really silky milk foam is the steam flow rate, not the power, especially for low volumn milk. The real strict test of the steam performance of a machine is to steam low volumn milk. Only good steam performance can use low pressure but high flow rate to steam low volumn and silky milk foam in 10 to 15 seconds. Actually I often steam only 120g milk with a 250ml Motta milk pitcher. I used the same Vortex steam tip (old version) on 3 machines, FAEMA Lambro (3.5L with 1500W heating element), Lelit Bianca (1.5L with 1400W heating element), and Nurri Leva (1.8L with 1000W heating element).

The FAEMA Lambro used a Sirai pressurestat and had the biggest diameter of the copper pipe between the boiler and the steam wand, no inner tube in the steam wand. The steam copper pipe diameter is just a little bit smaller than it of the water copper pipe behind the grouphead. Of course, it can have this high steam flow rate because it has the big boiler. The steam pressure drops slowly when steam milk. I adjusted the pressurestat to 0.7 bar to 0.9 bar and it could make the best milk foam of the 3 machines. Real commercial grade.

The Lelit Bianca has the smallest diameter of the steam copper pipe. I took out the inner tube of the steam wand and the milk foam quality was improved, but the steam flow rate was still lower than the 2 other machines. I had to set the steam boiler temperature to 127C or above to make good milk foam. The milk foam quality was not bad, but not as good as the other 2 machines made. With the inner tube, the best result was using the stock 2 big holes steam tip. The milk foam was good too, but could not compete with the Vortex steam tip without the inner tube. The worst was using the Vortex steam tip with the inner tube.

The Nurri Leva has the same (or a little bit smaller) diameter of the steam copper pipe as it of the FAEMA Lambro. I set the boiler temperature to 119C (0.9 bar) to steam 120g milk. The milk foam quality is near but not equal to the FAEMA Lambro's, and I have to concentrate on steaming, not as easy and stable as using the FAEMA Lambro. Using the stock 2 hole steam tip I cannot made the milk foam as good as using the Vortex. I also tried to take out the inner tube from the steam wand, but all things were worse no matter using the stock steam tip or Vortex.

Forgot to say, the steam pressure test video was using the stock 2 hole steam tip.

January 27th, 2023, 2:23 am

bakafish wrote:Lelit Bianca has 1.5L steam boiler with 1400W heating element and a dedicated PID for the steam boiler, so it has the constant steam pressure when steam milk. The inner tube diameter is smaller, the copper pipe between the steam boiler and the steam wand as well, so its steam flow rate is lower. I took out the inner tube of my Lelit Bianca and replaced the steam tip with the Vortex 3 hole steam tip, https://baristawarehouse.com.au/product ... -steam-tip. The steam flow rate was increased and it still had constant pressure.

IMO, the Nurri Leva's steam pressure drops quickly due to the design. If it uses a higher wattage heating element and a dedicated PID for the steam boiler, even it cannot have constant steam pressure, at least it would never drop so quickly, and it will not increase too much cost.

I had said, the key to make really silky milk foam is the steam flow rate, not the power, especially for low volumn milk. The real strict test of the steam performance of a machine is to steam low volumn milk. Only good steam performance can use low pressure but high flow rate to steam low volumn and silky milk foam in 10 to 15 seconds. Actually I often steam only 120g milk with a 250ml Motta milk pitcher. I used the same Vortex steam tip (old version) on 3 machines, FAEMA Lambro (3.5L with 1500W heating element), Lelit Bianca (1.5L with 1400W heating element), and Nurri Leva (1.8L with 1000W heating element).

The FAEMA Lambro used a Sirai pressurestat and had the biggest diameter of the copper pipe between the boiler and the steam wand, no inner tube in the steam wand. The steam copper pipe diameter is just a little bit smaller than it of the water copper pipe behind the grouphead. Of course, it can have this high steam flow rate because it has the big boiler. The steam pressure drops slowly when steam milk. I adjusted the pressurestat to 0.7 bar to 0.9 bar and it could make the best milk foam of the 3 machines. Real commercial grade.
image

The Lelit Bianca has the smallest diameter of the steam copper pipe. I took out the inner tube of the steam wand and the milk foam quality was improved, but the steam flow rate was still lower than the 2 other machines. I had to set the steam boiler temperature to 127C or above to make good milk foam. The milk foam quality was not bad, but not as good as the other 2 machines made. With the inner tube, the best result was using the stock 2 big holes steam tip. The milk foam was good too, but could not compete with the Vortex steam tip without the inner tube. The worst was using the Vortex steam tip with the inner tube.
image

The Nurri Leva has the same (or a little bit smaller) diameter of the steam copper pipe as it of the FAEMA Lambro. I set the boiler temperature to 119C (0.9 bar) to steam 120g milk. The milk foam quality is near but not equal to the FAEMA Lambro's, and I have to concentrate on steaming, not as easy and stable as using the FAEMA Lambro. I also tried to take out the inner tube from the steam wand, but all things were worse.
image

0.7-0.9 bar on the Lambro????

January 27th, 2023, 2:28 am

jontyc wrote:Correct, not a problem with shots being wrecked with levers (one of the reasons I could never go back to pump brewing).

However the Izzo lever is not off the hook. Single boiler - so filling the group chamber with water can frequently take the boiler low. Shot protected, but goodbye steam pressure.

So the Nurri/EVO arrangement of lever and two smaller boilers is the ultimate IMO.

I' ve never had that happen with my Pompei.Maybe your waterlevel is too low.The amount of water the solenoid lets into the boiler is way too little to affect steampressure.This machine needs to be run at 1.3-1.4 bar boilerpressure.
Even on my little Lambro I have enough steampower left to steam when I add a pretty big amount of cold water.

January 27th, 2023, 2:45 am

bakafish wrote:...
FAEMA Lambro (3.5L with 1500W heating element), Lelit Bianca (1.5L with 1400W heating element), and Nurri Leva (1.8L with 1000W heating element).
...

I was once told that horizontal boilers like from the Lambro make better steam than vertical boilers like on the other 2 machines. Asking for a reason the position of the heating element allowing for more steam volume in the horizontal boiler was attributed with the difference.
I am really not sure if this is true, but given that physics are physics and steam always being as dry as it is this all can only relate to the temperature of the steam exiting the steam tip.
Theoretically, a good heat conductor steam wand and tip that is well insulated to the outside and is thermally well connected to the hot boiler should give the hottest steam and therefore the driest.
Hell, maybe we get actively heated steam wands soon

#197: Post by **bakafish** » January 27th, 2023, 3:13 am

espressotime wrote:0.7-0.9 bar on the Lambro????

Yes.

January 27th, 2023, 3:17 am

That's real low.Mine' s at 1.35.

January 27th, 2023, 3:43 am

Yes, pretty low. Taiwan summer room temperature is over 30C for 4 to 5 months. The grouphead surface temperature was over 88C, so it was ok in summer, but needed a warming flush or using an portafilter with a needle valve to warm up the grouphead in winter.

January 27th, 2023, 3:55 am

I never measured grouptemperature but puck tenperature during the pull.
On my pompei it went from 96-94 during the pull.That was at 1.25 bar.
Anything below that resulted in undrinkable and sour espresso.