City roast - odd behaviour in naked portafilter

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Espresso_Monkey
Posts: 260
Joined: 12 years ago

#1: Post by Espresso_Monkey »

Hey all
This blend - Brazil Ponto Alegre, Guatemala El Zapote & Tanzania Karatu - is roasted light, maybe around a City roast.

This is related but not exactly the same as another post I opened:
City Roast - When do aging beans become bitter?

The beans come from the same third wave roaster as the above post. They are fresh, stored well etc etc...

This issue is this: The extraction starts lovely, even etc. But after ~15 seconds, the shot becomes uneven. 'Pockets', for lack of a better descriptor, appear in the shot (i.e. I can see the PF).

It could be my technique, but I'm pretty confident its not. This is not something that I have observed before...(my usual beans are a darker roast).
This leads me to question the beans - is the extraction some how exhausted earlier than usual? Then why doesn't it just blond?

Insights from more experienced peers sought.

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hipporun
Posts: 192
Joined: 9 years ago

#2: Post by hipporun »

The "pockets" you speak of are called channeling. Check the search function, you can find some tips on reducing it. Just note that City roasts do extract a bit funky, at least different from what you are used to. Less crema, lighter ect.

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nickw
Posts: 559
Joined: 11 years ago

#3: Post by nickw »

Sounds like channeling. Lighter roasts create less fines than darker roasts whilst grinding.

I thought I had good technique until I got a bottomless filter.
Then I thought I had good technique until I started with really light roasts.
Then I thought I had good technique until I aligned my Versalab M3 and got an EK43.
Now I know it's a constant learning process.

I like what David Schomer had to say here:
Coffee is enormously complex... like Ukranie nested dolls. And each time you solve one, there's another inside, something you didn't know about.
https://www.youtube.com/watch?v=pUYEOBU4C_s

Cheers!