Puzzling extraction difference - Olympia Cremina vs. La Marzocco Linea Mini

Beginner and pro baristas share tips and tricks.
atao

#1: Post by atao »

I've been trying to match the quality of espresso of my Cremina with my Linea Mini.
I'm using the same grinder (Niche Zero), same dose (14.5g), same beverage yield (28g), same temperature (to my best ability, ~200deg), and the Cremina consistently hits ~20% extraction and the LM about 18% total extraction, measured with a refractometer.
I then varied temperature (up) on the LM and also tried a tighter and coarser grind, and also a larger basket (going from the 14g to the 17g). The coarser grind (with same beverage yield) resulted in lower extraction levels (about 16-17%) and the tighter grind didn't achieve much more extraction yield than the baseline grind.

So i'm scratching my head about what could be causing this rather large gap in extraction. The espresso from the Cremina is very pleasantly sweet and balanced while the LM's espresso is pretty clearly underextracted.

I mean, there's pressure profile. I could try to lower the pump pressure. I could try the gicleur mod (a bunch more work).
Any other ideas?

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sadbox
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#2: Post by sadbox »

Two things are sticking out to me here:

The first is that basket diameter will force a recipe change. With your fixed dose in a smaller diameter basket you'll end up having a thicker puck on the Cremina. To accurately compare between them you would have to adjust both your dose

The second, and arguably more important is the difference in extraction profiles. Your LMLM has a super high flow rate, and later in the shot when 18%+ of your puck as ended up in the cup that flow rate will make channeling worse.

My experiences with levers and my LMLM mirror this experience as well.
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jmotzi

#3: Post by jmotzi »

18-20% TDS??? are you sure? 18% TDS for a 28g beverage is 5g coffee extracted, which out of a 14.5g dose is a 35% total extraction.

Perhaps you mean 18-20% total extraction (which is about 9-10% TDS for your 28g beverage)?

JM
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pcofftenyo

#4: Post by pcofftenyo »

atao wrote:I've been trying to match the quality of espresso of my Cremina with my Linea Mini.
I'm using the same grinder (Niche Zero), same dose (14.5g), same beverage yield (28g), same temperature (to my best ability, ~200deg), and the Cremina consistently hits ~20 tds and the LM about 18 tds, measured with a refractometer.
I then varied temperature (up) on the LM and also tried a tighter and coarser grind, and also a larger basket (going from the 14g to the 17g). The coarser grind (with same beverage yield) resulted in lower extraction levels (about 16-17%) and the tighter grind didn't achieve much more extraction yield than the baseline grind.

So i'm scratching my head about what could be causing this rather large gap in extraction. The espresso from the Cremina is very pleasantly sweet and balanced while the LM's espresso is pretty clearly underextracted.

I mean, there's pressure profile. I could try to lower the pump pressure. I could try the gicleur mod (a bunch more work).
Any other ideas?
That's like trying to make a zebra a shetland pony.

While I usually refrain from using absolute words, I've got to think that a spring lever and a rotary pump will almost always provide different shots. Different rotary pump espresso machines will pull different shots too: LM, Unic, Speedster, on and on...

atao (original poster)

#5: Post by atao (original poster) »

jmotzi wrote:18-20% TDS??? are you sure? 18% TDS for a 28g beverage is 5g coffee extracted, which out of a 14.5g dose is a 35% total extraction.

Perhaps you mean 18-20% total extraction (which is about 9-10% TDS for your 28g beverage)?

JM
Yes total extraction

lessthanjoey
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#6: Post by lessthanjoey »

atao wrote:I've been trying to match the quality of espresso of my Cremina with my Linea Mini.
I'm using the same grinder (Niche Zero), same dose (14.5g), same beverage yield (28g), same temperature (to my best ability, ~200deg), and the Cremina consistently hits ~20% extraction and the LM about 18% total extraction, measured with a refractometer.
I then varied temperature (up) on the LM and also tried a tighter and coarser grind, and also a larger basket (going from the 14g to the 17g). The coarser grind (with same beverage yield) resulted in lower extraction levels (about 16-17%) and the tighter grind didn't achieve much more extraction yield than the baseline grind.

So i'm scratching my head about what could be causing this rather large gap in extraction. The espresso from the Cremina is very pleasantly sweet and balanced while the LM's espresso is pretty clearly underextracted.

I mean, there's pressure profile. I could try to lower the pump pressure. I could try the gicleur mod (a bunch more work).
Any other ideas?
I think it's a pressure profiling / preinfusion thing. You're likely getting a lot more thorough preinfusion on the cremina, and then can lower the pressure through the shot to maintain a reasonable flow-rate. You're probably blasting the puck with a high water debit on the LMLM and then maintaining 9 bar throughout which will rarely lead to as even extraction as you can get on the Cremina. One thing you can do is add a paper filter to the bottom of the portafilter. That tends to increase extractions a bit.

drH
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#7: Post by drH »

Out of curiosity which coffee are you using? Dark? Light?

I expect you'd see less difference with a darker vs lighter beans.

Do you have the new preinfusion capabilities on the Linea? Try increasing the pre-wetting to 5-6seconds and see if it helps.

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atao (original poster)

#8: Post by atao (original poster) »

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.

sheedapistawl

#9: Post by sheedapistawl »

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 ....

sheedapistawl

#10: Post by sheedapistawl »

I'd also read this for the theoretical and empirical backing on my previous post

https://www.cell.com/matter/fulltext/S2 ... 19)30410-2