Do different coffees make puck prep more challenging?

Beginner and pro baristas share tips and tricks for making espresso.
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#1: Post by fxroberge »

Hey all!

Still relatively new in my espresso journey, but never drink the same coffee twice. I've started to notice a trend that some coffees when I get them dialed in (1:2.2ish) in 30ish seconds, tend to channel no matter how careful I am in puck prep. I wdt and pay attention to flat tamping.

I've started to up the dose and grind coarser on these coffees which seems to help from a taste perspective, but wondering if any seasoned home baristas have run into this and their thoughts.

In the pursuit of the perfect cup

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#2: Post by RapidCoffee »

Yes. It's generally accepted that lighter roasts are harder to extract.

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#3: Post by another_jim »

Yep, very light roasts grind with less fines, so they tend to gush in espresso. With some, grinding extra fine works, down to Turkish, will solve the problem. But others, when ground that fine, just taste wimpy, like dishwater.

Here's where the handstands begin. Very large flat burrs can create a less flat taste at very fine grinds. You can also overdose in larger baskets, or do "blooming" shots, with a very long preinfusion and very fast flow afterwards. Mostly, to me, the result isn't worth all the effort; but many disagree.
Jim Schulman


#4: Post by malling »

Lighter roast are harder to work with and pull yes, often you need to grind finer and it just means more care needs to be implemented in WDT, minor mistakes and you easily get some rather noticeable channeling.

There been different approaches to overcome this like pulling turbos at a more coarse grinds, doing long preinfusion, blooming espresso. All require the use of a large flat burr grinder that does well at those style shots and precision baskets.

But distribution is much easier on darker roasted coffee especially on more traditional burrs, that's why you could see people do some lazy distribution of the past and get away with it.

fxroberge (original poster)
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#5: Post by fxroberge (original poster) »

Hmmm, yeah I know light roasts are harder to extract, but didn't know that would manifest in channeling. Thing is, I don't think this coffee I'm have trouble with is particularly light, it's more medium-light Rwandan bean.

It might be I'm not doing myself any favours on the grinder front, I have a P64 with SSP MP burrs, so that probably doesn't make it any more forgiving, however, I've been fine with other coffees which is why I asked.

I'd love preinfusion and flow control on my machine, but would need to modd it to get those... Something to think about
In the pursuit of the perfect cup


#6: Post by malling »

It dos if you grind very, very fine, there been test to show there is a threshold in grinding finer, when passing that threshold server channeling chance increases noticeably and extraction start dipping.

Distribution of excessively find grind are just increasing the difficulty level in creating a proper distribution. It's largely the reason for the popularity of turbo shots (especially as most don't have machines that do long PI) as you here are using a coarser grind that are easier to do a proper distribution with and those minimise channeling.

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#7: Post by mrgnomer »

Light roasts especially those specifically roasted for drip coffee is a challenge. The roast profile does not favour espresso extraction.

I find finer grind, higher brew temp start, longer preinfusion and a high pressure extraction start that ramps down to a low pressure finish helps for good tasting even extraction. I don't know if tampers make a difference really but I found flat tampers and being careful to evenly seal the edges help for me. Good WDT as well.
LMWDP #116
professionals do it for the pay, amateurs do it for the love

fxroberge (original poster)
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#8: Post by fxroberge (original poster) »

So, just pulled probably my best shot.

I have a Silvia with a PID installed. I bumped my dose 1.5g, ground a bit coarser. Upped the preinfusion duration and wait. During preinfusion I opened the steam wand to try for low pressure. Let is sit for 15 seconds then the shot pulled.

A bit of channeling at the end as the puck degraded, but over all pretty successful. Thanks everyone!
In the pursuit of the perfect cup


#9: Post by bullet08 »

Nor really. I just follow my routine, and usually things come off fine. Then again, I only use Italian brand beans. Don't like too acidic coffee.

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#10: Post by LondonBunny »

I have had a few problem coffee beans, just unsuitable for (my) grinders and espresso machines.

A few have always channelled, as you describe, or then when ultra fine tasted weak, and some the opposite where they always clog and extract too slowly.

I just throw them away or use them with the Aeropress.