Swells in stripes...Channeling?

[TimEggers]

Hello friends,

I have noticed that at times I get swells in my stripes during an extraction. To better describe it the stripes sort of dance or swell in spots. The stripe will be even and then swell briefly then return to a more normal even stripe.

Is this a sign of channeling? I don't get gushers or shooters, but looking at the stripe it appears the flow is uneven in the sense the stripes swell and bulge as if getting moments of accelerated flow before the returning to a more stable flow.

If my descriptions aren't good I'll try to get a video of them, but my camera isn't that good...

[appa]

How do your pucks look afterwards?

[TimEggers]

[DC]

You mean one of those stripes suddenly swelling and then going back to normal?

I'd guess it meant faster flow, see it often at the end of shots. Never noticed a taste difference when I do see it though

[cannonfodder]

I believe I have a video showing what you describe in the Dialing in a new espresso machine, a step by step guide. I don't remember which video (I am at work and gvideo is throttled way down) but you may want to give them a quick view and see if you notice the same behavior.

To answer the question, yes, it is channeling. When you have a meltdown you get the jets spraying you in the eye. When you have more minor channeling you will get a bulge from the basket but no squirting. It will also present itself as a sudden large circular blob that appears on the cone and then subsides back to the striping.

[TimEggers]

I believe I have a video showing what you describe in the Dialing in a new espresso machine, a step by step guide. I don't remember which video (I am at work and gvideo is throttled way down) but you may want to give them a quick view and see if you notice the same behavior.

To answer the question, yes, it is channeling. When you have a meltdown you get the jets spraying you in the eye. When you have more minor channeling you will get a bulge from the basket but no squirting. It will also present itself as a sudden large circular blob that appears on the cone and then subsides back to the striping.

My fears confirmed. Thank you. I have much work to do. Luckily I don't see it in every shot. Maybe 25% of them though...

[appa]

Hi Tim

I dont see signs of really bad chanelling (holes in the puck, etc),
maybe its just slight..

Can you taste the difference when this happens?

[cannonfodder]

Around second 25 there is sudden light spot that appears in the front of the cone and then goes away. Is that what you are referring to?

[HB]

I have noticed that at times I get swells in my stripes during an extraction. To better describe it the stripes sort of dance or swell in spots. The stripe will be even and then swell briefly then return to a more normal even stripe.

Fresh coffee that's degassing can do that early to mid-extraction, or blends with high-crema producing coffees like Robusta. Otherwise I'm with Dave, sounds like (minor) pinholing.

[TimEggers]

Around second 25 there is sudden light spot that appears in the front of the cone and then goes away. Is that what you are referring to?

Yeah! That's exactly it but mine are usually more subtle and I do see them mostly in the early part of the extraction. And yes the coffee is super fresh (3 days old). The shots do taste great though (but then again I'm still learning thanks to you guys).

I have some more work to do...(but man this is so much fun). I love this place!

[cannonfodder]

the coffee is super fresh (3 days old).

Hmm, super fresh may be too fresh. I wonder if you are simply seeing a blast of excess CO2 from the overly fresh beans. I usually start using my roasts around day 3, they tend to peak at around day 4/5 and never last beyond day 8. That first couple of days tend to produce excessive crema because the beans have not finished out-gassing. The crema will gush from the basket but then goes flat in seconds.

[kinkbmxco]

I have been noticing exactly what you all describe. I just started roasting my own beans and being the impatient person I am, I have been using them up pretty quick. I try and let them sit for at least a day or so hahaha. But when pulling my shots I get this burst of crema towards the middle/end of the shot like I need do grind finer. Then when I am done steaming my milk I only have a very thin thin layer of crema. I guess I have to wait a couple more days for my roast do degas.

[cannonfodder]

Yes you should. You will not get the sharp baking soda taste after a proper degas as well, unless you like that. Degassing has been hotly debated, some believe in it, others do not Why coffee needs to rest before making espresso. I think it is strictly personal preference. If you like the taste of your coffee while the beans are still warm from the roaster then have at it. If you prefer the taste after it has gone flat two weeks post roast, you have my condolences.

[Psyd]

If you prefer the taste after it has gone flat two weeks post roast, you have my condolences.

I still tell folk that if they prefer the grocery store bin coffee then they have my sincere, green-eyed monster jealousy. Oh, to be back in the day when I could fall in love with a grocery store bean out of my Krups steamtoy. Life was much simpler then, and I loved my shots out of that thing as much as I love my shots out of the Astoria. I like the Astoria shots much better now, I just didn't have it then...