Bad flow and channeling near end of shot

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barouet
Posts: 34
Joined: 7 years ago

#1: Post by barouet »

Hi Home Baristas,

This is my first post on the forum.
I'm having issues with my flow rate and channeling occurring near the end of the shot.
I pull 14.5g in a 15gVST basket that I WDT. Beans are 12 days old. Grinder is a 2 week old Eureka Atom, machine is a QM Silvano.
Before I tamp I make sure all is even and level (WDT) and no matter how hard I try I always get similar uneven flow ending with watery channeling.
Here's a video of the typical shot I get.
http://www.vimeo.com/200483777

The taste is harsh, salty.

Any cue on how to improve this?

Thanks
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MB
Posts: 792
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#2: Post by MB »

Does the taste lean towards bitter (citrus peel, unsweetened dark chocolate) or sour (citrus juice or Greek yogurt)?
If it's balance between those two, but just too intense, then the advice is to grind finer and reduce the dose to maintain the flow. If it is too bitter or sour, then those can be tweaked as well. See this thread: Espresso 101: How to Adjust Dose and Grind Setting by Taste
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h3yn0w
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#3: Post by h3yn0w »

Seemed a little slow, I'd coarsen it up a bit. Have you weighed your ouput? Stop the shot at 28g to start and then adjust from there.

barouet (original poster)
Posts: 34
Joined: 7 years ago

#4: Post by barouet (original poster) »

Thanks for your reply.

The taste was too intense, more on the greek yogurt side.
The output was 30g.

I'm more worried about the flow, don't you feel there is something wrong going on at the last half of the extraction?

Thanks
LMWDP #585

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MB
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#5: Post by MB »

In that case, just grind finer for flavor and it might help your flow issue as well.
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sprin001
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#6: Post by sprin001 »

I had similar problems to this in the past and you can grind too fine which leads to those issues. Try coarsening a bit, increasing dose while doing good level/tamp (your distribution of flow looks great at the start) and see if it helps at all. Also, vibratory pumps take a while to build pressure, see if your pressure is jumping or moving around after the 10 sec mark.

h3yn0w
Posts: 476
Joined: 13 years ago

#7: Post by h3yn0w »

barouet wrote:Thanks for your reply.

The taste was too intense, more on the greek yogurt side.
The output was 30g.

I'm more worried about the flow, don't you feel there is something wrong going on at the last half of the extraction?

Thanks
Different beans will behave differently so I don't think there is one universal answer. But regarding flow, most shots, left long enough, will flow like yours did. If you are getting 30 grams that's just over a 2:1 (normale) ratio. Personally I would grind a bit coarser and also try lowering the brew ratio a touch and see whether the change is positive or negative in flavour.

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sweaner
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#8: Post by sweaner »

Have you tasted a shot cut off earlier, maybe at 25g?
Scott
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bluesman
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#9: Post by bluesman »

There's a lot of good stuff in this thread. But I never see anyone else mention a factor that I've found to be very important, and that's how you apply tamping pressure. I find that slow and steady placement and application of force eliminates all but very rare errant flow. I seat the tamper slowly and increase the applied force just as slowly, holding the full pressure for a few seconds. Then I gently let up on the force and only turn the tamper through a small arc as I lift it out. All of my flow related problems seemed to happen when I tamped too fast.

I also cut my naked PFs so that there's a mm or two below the basket, and I rounded the bottom edge. That lets it sit firmly against the mat for consistent tamping. I've seen many cut too short for the baskets used, so the bottom of the basket rested on the underlying surface. I don't think this lets you tamp well if the basket bottom flexes.

barouet (original poster)
Posts: 34
Joined: 7 years ago

#10: Post by barouet (original poster) »

Thanks everyone.

I tried yesterday and today with a different coffee. Coarser setting, 1:2 normale, still the same end of shot phenomenon. I tried with our without WDT. Taste was unbalanced anf salty.

I quickly tried 17.2g in a 18g VST and the flow seemed much more constants, with less of this watery channeling flow.

Also, my grinder is 2 week old. Could this be related to break-in?
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