Puzzling extraction difference - Olympia Cremina vs. La Marzocco Linea Mini - Page 3

Beginner and pro baristas share tips and tricks.
lessthanjoey
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#21: Post by lessthanjoey »

atao wrote: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 :)
What paper filter did you use? Mine speeds it up quite a lot (kafatek robot filters), so it sounds like you have a very dense filter!

atao (original poster)

#22: Post by atao (original poster) »

it was an aeropress filter cut to fit the bottom of the basket

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pcofftenyo

#23: Post by pcofftenyo »

atao wrote:Is there a sort of manual preinfusuion I should try, like pouring a bit of hot water on the bed before locking the portafilter?
The LMLM _has_ pre-infusion. When you first move the paddle from right to left there is a delay before the pump activates. In that interval that is appx 1 sec the machine introduces line level pressure water to the puck.

2 things:
1-The app which may require a hardware/control board update if the machine is an early version, allows for the user to modify pre-infusion.

2-without the app or board change, the user can move the lever from off and on then back off again before the pump activates. Let puck swell a sec, repeat if desired or not, depending on results.

If you don't like the LMLM, I can find a home for it. Or the Cremina, for that matter.

atao (original poster)

#24: Post by atao (original poster) »

Yes, i'm well aware of this. I've said it a couple times in this thread that i don't have the hardware update.

Is it true that you can manually preinfuse by sliding the lever forward and backward? Doesn't that trigger the flush valve?

atao (original poster)

#25: Post by atao (original poster) »

Ok, some interesting developments.
I had to go to a new coffee (Counter Culture Hologram).

New baseline measurements:
LM: 15.5g dose -> 35.4 out -> 17.8%
Cremina: 14.5 dose -> 37.2 out -> 20.1%

And this did make me realize that my ratios were quite different, with LM about 2.3 and Crem at 2.6.
So i pulled LM in similar ratio:

LM: 16.6 -> 41.7 ratio = 2.5 -> 18.1%

This only bumped up the extraction % a little. I realize i changed 2 things, but anyways, i hadn't seen much extraction drift with larger doses, so.

Here's the interesting experiment:

LM: 16.6 -> 41.6 but with pre-wetting (i pour about 1tsp cold water on puck and let it sit for 10 sec) -> 19.5%!

So, the pre-wetting took the extraction % up about 1.4%. That's rather significant.

I did try one shot with pre-wetting via the LM lever, where i prepare puck normally, and then instead of dumping cold water on the puck, i move the lever to the middle for a second, and then back to the OFF position and wait 10 seconds, then pull shot normally. This resulted in 19.1%, not quite as high as the cold water but still 1% higher.

So this leads me to think that i should be considering the programmable pre-infusion on the LMLM.
I haven't read those threads where people evaluate the pre-infusion. Is there any data there that either confirms or denies these observations above?

On a tangent, i'm all out of VST syringe filters. Anyone have a recommendation for an alternate source for them? Every time i buy them from VST i feel like i'm losing my shirt.

jpender

#26: Post by jpender »

atao wrote:On a tangent, i'm all out of VST syringe filters. Anyone have a recommendation for an alternate source for them? Every time i buy them from VST i feel like i'm losing my shirt.

I've used these and they work well enough. They are a little less expensive than the VST ones. There are cheaper syringe filters but I've read mixed reviews.

Some people use mini centrifuges. Careful tests (e.g. https://awasteof.coffee/2019/02/12/cent ... -espresso/) have been run that demonstrate that they work about as well as syringe filters. You can find used centrifuges on ebay. Even a new one can be had for under $200. They are a little more effort than a filter but still pretty easy to use. And having zero recurring costs has to be mighty tempting if you're using your refractometer frequently.

atao (original poster)

#27: Post by atao (original poster) »

I pivoted to Apollo from Counter Culture.

It has been a complete surprise to me that larger doses are yielding greater extraction percentages.

With a yield of about 2:1, my 18gr shots in a 20g VST are extracting only ~18-19% while my 19gr shots are yielding ~20% extraction.

This is a total surprise to me honestly. It has never been a tool in my arsenal that to increase extraction, you should increase the dose! I believe that I read threads on this very forum (was it from another_jim) where the guidance was that if you're having trouble extracting enough, then focus on lower doses and finer grinds.

This experiment was done with only a few shots but assuming it's repeatable, it leaves me wondering if this is simply a well understood behavior of espresso brewing (that I've clearly been ignorant to) in general, or is this more of a LMLM dynamic.

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atao (original poster)

#28: Post by atao (original poster) »

By the way, thank you for the syringe filter tip @jpender, I got them and they're working out well.