Help with spraying / channeling issue

[echappist]

I'll start by saying that this is a more recent phenomena, noticeable only in the last year or so. Before this, I actually didn't realize that channeling and spraying are issues. I don't have a good video of my extractions from late 2019, but the extraction at least appeared okay circa late 2018 (see video below; have to click through to link; I don't know how to embed it here).

https://drive.google.com/file/d/1g0-...53EV3fz_s/view

Lately, I've been getting a lot of spraying (even with fresh beans), and i'm at a loss at what to do. If I grind coarser, the spraying actually gets worse. I'm not amused that one of the top videos (from Clive Coffee) basically suggests buying $300 worth of gadget to "remedy" the issue.

Perhaps at least the burrs in my grinder have given up the ghost and need to be replaced? They've been used for ~9-10 years and have yet to be replaced. I would think this would be more likely, given that I previously didn't have an issue. Or perhaps the grinder itself needs to be replaced, so I could dial it things better? This seems doubtful, as I have had the same set-up going back ~six years.

Any other suggestions?

[J_B]

Can you attach a video of the extraction now, where it sprays and channels?

Do you use any kind of distribution tool for the grinds when they are in the basket? This can help to reduce clumping which creates channeling if not distributed properly. On that note, if you’ve noticed a difference in grind appearance, barring any differences in coffee density and roast level, this can be a good indicator of your burrs being worn. The need to adjust to a progressively finer grind setting to achieve the same grind size is also a good indicator.

[echappist]

Thanks for the input. I don't currently use any distribution tool (never seemed to have needed it; then all the sudden I now do). Do you have a recommendation?

I'll take another video once I get a newer batch of beans. Current one is getting a tad old (perhaps up to three weeks since roasting?)

My wife has also given me the go ahead to buy a Niche grinder, but as that won't be available for a while, I want to see if I could nail things down on the existing equipment.

[dashDustin]

in your case, i'd suspect the burrs are toast. if you want to try something...

https://levercraftcoffee.com/collect...ibution-tool-1

I recently made my own one of these with a wine cork and 3d printer cleaning needles (.4mm). I'm surprised by how much it has actually helped.

[echappist]

That's really neat, thanks for the suggestion.

If at all possible, I'd like the gadget spending to stay under $100, so I can have some left over for the Niche grinder.

I'm also considering a funnel, but with the way the Niche doses, that might not even be necessary.

[tanghy]

you can save on the tool if you use the NSEW method or stockfleth's method for hand distribution

also make sure you are using the same dose in by weighing the grounds

[echappist]

I can report back that an upgrade in grinder (Baratza Preciso to Niche Zero) seems to be the right move so far.

I'm still experimenting with optimum dosage and coarseness, but the excessive spraying has largely disappeared. Nothing else in my prep has changed. I'm also finally beginning to get aroma from my shots, too.

It used to be that I couldn't get a decent shot from my decaf beans, as what came out of the portafilter is probably best described caffé incontinentia: numerous channels spraying liquid literally all over the counter. Any time I tried to adjust grind size, it just seemed to have made things worse.

I realize that a set of replacement burrs on the Baratza would have probably solved the spraying issue, but overall, the Baratza left much to be desired. For one, I can finally adjust coarseness independently of dosage, which was nearly impossible on the Baratza. I'm now actually dosing 0.3 g less than I used to (~16.5 g now vs 16.8 g previously), as anything less than 16.7 g from the Baratza meant a watery swill, even back when the burrs were not worn. And the other is that the coarseness setting often get changed due to vibration of the grinder, which was quite annoying, as an "8"-grind one day could be a "9"-grind another day.

[9tubes]

A couple of thoughts:

In the video the pump goes on at the beginning, then quickly off then on again. This can crack a puck and cause channeling.

Also, the pump noise varies during the shot. It could be that there are pressure variations that are causing channeling. The pump sounds like a vibratory pump. They can get a bit of calcification on the inside that inhibits the pump piston from moving full stroke. It could be that yours is in need of cleaning. Or replacing -- they're pretty cheap and they are easy to replace for a bike-geek-mechanic type person.

BTW, +1 on a Niche Zero. Excellent grinder. None better for the money, or even twice the money.

[9tubes]

Also, remove your water dispersion screen to clean behind it if you haven't recently. That can cause problems too.

[echappist]

Thanks for the helpful suggestions. I don't clean the dispersion screen often enough; will def do that.

As for the pump temporarily shutting off at the beginning, that's the pre-infusion process on the Rancilio Silvia. I should really look into dialing in that part (or perhaps get rid altogether).

[9tubes]

Ah, I see. If Rancilio set it up that way then there probably isn't enough of a change in pressure at the beginning to damage the puck. It's likely just a little squirt of water at low pressure to wet the puck. I suspect what I heard is not the cause of your problem.

It's not the ramp up in pressure that messes with the puck integrity. It's the release from high pressure. Often the whole puck will get sucked upwards by the release from full pressure. Starting the pump again after that will not push the puck down and re-seal the puck to the bottom of the portafilter; it will fracture the puck instead or water will just run around it.