sheedapistawl wrote:Try adjusting OPV down to 6 bars and then run both the tighter and coarser grinds I would bet you can bump up extractions - with an extended Pre if you can manage it on the LMLM

TFW when a 50-60 year old spring lever design with a declining pressure and temp profile is better for extraction than "modern" machines ....

Creminas don't have springs, except for the new SL.

atao wrote:I'm pulling a light-ish roast: Ritual Ethiopian Nano Challa.
I'll plan to try the paper filter trick, and to lower the pump pressure, but I don't have the pre-infusion ability.

This makes sense to me and I agree with sadbox about the need to adjust recipes.

Since the LMLM has a bigger basket I'd increase the dose to thicken the puck and try again. That alone won't get you there but it's a start. Next will be to experiment with tightening the grind increasing the temperature a little and running a longer ratio. If you are doing 1:2 on the Cremina maybe 1:2.5 or more will work better on the LMLM.

Aside from the Cremina I have a HX machine and I can usually get similar tasting shots on both with the right adjustments. The catch is that the Cremina, with its long preinfusion ability, can deliver that taste in a much more concentrated, lower volume shot. The LMLM is one of the best machines on the market but just isn't designed for Slayer-style extractions. But, I'm convinced you'll get the right flavors with some more experimentation.

Quick update.

I adjusted LM pump pressure from 9.5 blind to about 7 blind.

Resulting extraction was a bit faster but with same total weight output, extraction % was largely similar.

I tightened the grind a full tick on the niche and pulled another shot and oddly enough the extraction % fell from 18.3 to about 17.8.

Paper filter on bottom of basket with the baseline grind setting slowed the shot way down and yielded a very slightly higher extraction%, 18.4, probably within noise.

Then I ran out of coffee

I'll probably pick up a bit more coffee and try to adjust the dose upwards, but I don't feel like I'm seeing a strong signal of the right direction to go.

Is there a sort of manual preinfusuion I should try, like pouring a bit of hot water on the bed before locking the portafilter?

Have you considered replacing your restrictor with the smaller 0.6mm? Perhaps the reduced flow rate would help alleviate your problem?

Yes, although that's a bit more work, and i was hoping to exhaust easy ideas first. I've also been a bit skeptical about the 6bar + 0.6 gicleur thing because it kind of came and went, it's not like everyone was overwhelmed with it's effectiveness. I saw a few folks (nuketopia) that tried it and abandoned it.

Do you have the wireless app control board in your LMLM?

atao wrote:Yes, although that's a bit more work, and i was hoping to exhaust easy ideas first. I've also been a bit skeptical about the 6bar + 0.6 gicleur thing because it kind of came and went, it's not like everyone was overwhelmed with it's effectiveness. I saw a few folks (nuketopia) that tried it and abandoned it.

I have no personal experience with the Linea but I'm also skeptical of the 0.6 gicleur mod. The flow rate will only marginally affect the first couple seconds of pressure ramp and then the machine hits 9bar. Given that you can set pre-wetting time on the new Linea, I'd like to understand better what the reduced flow really achieves. Perhaps it can slow down the later end of the extraction a bit, but even then, if you weigh the output, does it matter? Maybe it's just a way to make the machine a hair more forgiving, which has merit. I talked to a couple baristas about this and neither seemed interested in the idea (maybe too much expertise?).

i don't have the new control board / preinfusion programmability

Seems like i should try pre-wetting ... Pre-wetting / pre-blooming the puck before extraction