Ages ago I was getting channeling. Someone here or on CG advised to stop tapping. I did. Sure enough, no more channeling. But, some years later I started tapping again, as my new grinder made really fluffy grounds. Well, no channeling. None of this makes any sense to me. But I do believe that it helps to settle the grounds so that they don't spill over when I distribute/tamp. BTW, I don't side tap, I tap the bottom on my silicone mat...not sure if it makes any difference from side tapping.

Side tapping with the tamper (or whatever) is super old school and originated as a way to knock the loose grounds around the inner sides of the portafilter onto the middle of the puck so they could be polished. Second wave standard was: overfill basket and finger swipe or Stockfleth (distribution AND dose), tamp, knock on the side with tamper, then light tamp with a slight twist-and-lift to polish.

This type of side tapping became discouraged for many reasons which I believe remain true though none are at all catastrophic. It dents your tamper (or whatever), it knocks the puck loose from the sides of the basket, we don't typically polish like that anymore to avoid puck disturbance, and the combination of better distribution from multiple vectors plus 58.x tampers that leave less loose material around the perimeter.

WDT started around the time third wave thinking emerged--late 90s to early aughts. It was all about the yogurt cup. The slap-shot-tap and hand taps around the portafilter are distribution techniques that were already in practice, but became more popular with OE and Perger. They are attempting to do the same things as WDT and various distribution tools. It is pretty easy to mix and match and do some, none, or all depending on your situation and preferences. I think Barista Hustle still champions portafilter tapping side to side and slapping down as their preferred distribution method.
https://www.baristahustle.com/blog/dist ... t-results/

Since most now dose with a 0.01 scale, the grounds likely sit too deep in the basket for Stockfleth to do its job, and that's what a grooming tool is for--marginal improvements over whatever distribution method is used. WDT seems to be needed before tapping when tougher clumping occurs--in my case when grinding very finely with lighter roasts. If grinds are fluffy or clumps aren't huge or hard, WDT won't hurt), a tap on the mat is enough. Dose, distribute (side taps and/or WDT), tap down on mat, level (if using), tamp (if not relying on leveler for that).

Now static (RDT), puck spritzing (is it almost like bloom? or like a whisper of preinfusion?), preinfusion and flow control are better understood, too, and they are informing all of the above.

So I do a lot of these now... of everything really...

Tap, tap, tap to avoid the fluffy grounds from falling off when I remove the funnel
Tap, tap, tap, to fill the gap that the funnel leaves behind when removed
WDT
Leveler
Tamp

I need to get a different funnel... realized this after giving away the one that I had...

The funnel that I gave away sat on top of the basket/portafilter... the one I am using now digs into the coffee grounds... so I tap tap tap when I remove it to fill that gap before using the leveler... getting another funnel like the one I had will eliminate one round of tapping from my workflow...

And will also avoid this from happening...






Also, and I have not tested this yet, with the new leveler that I got, it feels like I no longer need to tamp... in the video you see me using the tamper, but finding out that it might not be doing much. Will try a shot without that additional step as well... Could be that I have set the depth of the leveler to a point that is also causing the tamping of the grounds as I level them...

Video sounds awfully louder than in the flesh...
But all of this has been working great for me... no channeling at all... in either the Rocket or the LR...

Mat-O-Matic wrote:Side tapping with the tamper (or whatever) is super old school and originated as a way to knock the loose grounds around the inner sides of the portafilter onto the middle of the puck so they could be polished. Second wave standard was: overfill basket and finger swipe or Stockfleth (distribution AND dose), tamp, knock on the side with tamper, then light tamp with a slight twist-and-lift to polish.

...it knocks the puck loose from the sides of the basket, we don't typically polish like that anymore to avoid puck disturbance...

++1

Perfect explanation. There used to be lots of videos online showing tamp, tap, tamp, polish...halo or gush. Sometimes there would be multiple taps (knocks, really) interspersed with a series of tamps. Used to make me shudder.

After WDT (when used) I lightly tap the PF on the counter to settle the grounds, then tamp. Done.

Tidaka and Decent sell funnels that fit on the outside of the basket, thus avoiding digging a trench around the perimeter of the puck. Tidaka makes a great one for single baskets that I use every day.

I think it is important to distinguish between tapping before versus after leveling/tamping. I think the latter is far more likely to lead to channeling etc. The former should not.

I'm in John's camp. Tap on mat.

slybarman wrote:I think it is important to distinguish between tapping before versus after leveling/tamping. I think the latter is far more likely to lead to channeling etc. The former should not.

I do not do any tapping after leveling/tamping the puck... that would detach the coffee from the sides of the basket. I know, I did it once... and proceeded to start all over.

JohnB. wrote: Both of my grinders have dosers so the grounds are well mixed by the time they land in the pf. Tap, level, tamp. No issues.

You touch on a great point here, very relevant to this thread:

Dosers on grinders are also something that went out of vogue some years ago. Yet they do a couple of things really well, which is to deliver nicely dispersed grounds without clumps or static, still a challenge for many modern grinders.

I tap a little to distribute then tap on the counter x 3 to break down air pockets. WDT creates a lot of air pockets. So it's my final step before the distribution tool. I gave up tamping. Sometimes I don't use the WDT. Very little if any channeling. I was getting a lot of channeling until I started tapping the bottom of the portafilter on the counter top. On the 3rd tap you can actually hear the tone of the basket change as the grinds become more dense.

I keep my distribution very simple. I keep a few days worth of coffee in the hopper of my Mahlkonig K30. I dose based on timed grinding (calibrated with a scale when dialing in), tap the portafilter horizontaly a few times with my hand to level out the grinds, followed by tapping the portafilter downwards gently on a tamping mat a couple of times to settle the grinds, then tamp. I can grind, dose, distribute and tamp in 10 seconds. If you have a good grinder, I really see no need for all the complicated dosing and distribution methods that seem popular now. I usually use a bottomless portafilter and I get good looking pours and rarely see channeling.