Why tap the portafilter?

Beginner and pro baristas share tips and tricks.
wildlyesoteric

#1: Post by wildlyesoteric »

grind > dose > stockfleth > soft tamp > ever-so-gentle tap > 30lb tamp > 2oz 25seconds good shot, blond ~20seconds

then

same grind > dose > stockfleth > 30lb tamp > choke machine

slightly coarser grind > dose > stockfleth > 30lb tamp > 2oz 25seconds GREAT shot, not significant blondness before 25 seconds

repeat about 200 times to find the same results repeated again and again and again; so WHY tap the portafilter?

What I'm suggesting is that apparently no matter how you work that tap in there, there's going to be channeling. I've found that no tap = no channeling. From seeing the results of the tap I'm surprised that it hasn't yet been treated as an absolute faux pas. Maybe I'm full of it? This is consistent over 3 machines.. mid level commercials and a cheap home machine. I've tried all sorts -- from love taps to bitch smacks, so I know I'm not beating up the puck.


discuss

Maskedman

#2: Post by Maskedman »

The reason I tap is to avoid having stray coffee grounds around the group head, and I like the clean way it looks when everything looks perfect in the basket.

Sounds more like one of your steps is inconsistent, maybe your grinder has dull burrs or something that creates different results?

Because it sounds weird that a coarser grind and only leaving out the gentle tap would make your should blond 10 seconds later!

Thomas
- Ride it like you stole it!

wildlyesoteric

#3: Post by wildlyesoteric »

Edited for a slightly more realistic blond timing.

As for consistency -- I'd like to approach it reasonably, but I just can't imagine wild fluctuations in variables after seeing these results over a month of 80 drinks a day. There is beyond doubt far less evidence of channeling on the surface of the puck or around the edge when the tap isn't used. I know it's pretty and damn well chronically habitual, but as long as you're still wiping the basket rim and PF ears there isn't going to be any more grounds contacting the gasket.


PS: "Ride it like it's stolen" classic North Shore mountain bike mantra.

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Spironski

#4: Post by Spironski »

This is how I do it: grind> dose> Stockfleth-like thing> then tap> 22kg tamp (45lb?)> lock it in gently > great shot, no channeling.

I think the tap is needed to avoid air being trapped in the puck, and it makes it more solid. You can do the same with almost everything: try putting things like sugar in a container and fill it to the brim, after tapping there is still room for more. Heck: I even do it when I put coffee beans in the airtight container. I think the effect of tapping here is bigger than when I would try to compress the beans in the container. Isn't that why they use these big vibrators when they pour out concrete floors?

So I figure this will be the same with coffee ground (?)

bcquinn1

#5: Post by bcquinn1 »

Which kind of tap are we talking about?

A) Tapping the portafilter with your tamper after you've tamped, or
B) Bumping the whole portafilter on the counter after you've dosed?

In either case I don't agree that a tap is needed to avoid trapping air in the puck.

Most folks I know would tell you to do away with the "A" tap completely, or if you have to, give it the gentlest nudge with the handle of your tamper. Tap too hard, and you can spoil the seal you've created between the coffee and the basket wall, causing side channeling.

I've seen some people use "B" as a kind of quasi-distribution (Heather Perry thumps her portafilter after grinding to settle the coffee), but more often than not I've seen people use it as a way of measuring the coffee when updosing. E.g., I fill the portafilter with ground coffee - if I thump it two times, then brush off excess, I usually end up with an 18g dose. No thumps, I'm at 15g.

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timo888

#6: Post by timo888 »

wildlyesoteric wrote:grind > dose > stockfleth > soft tamp > ever-so-gentle tap > 30lb tamp > 2oz 25seconds good shot, blond ~20seconds

then

same grind > dose > stockfleth > 30lb tamp > choke machine

slightly coarser grind > dose > stockfleth > 30lb tamp > 2oz 25seconds GREAT shot, not significant blondness before 25 seconds

repeat about 200 times to find the same results repeated again and again and again; so WHY tap the portafilter?

What I'm suggesting is that apparently no matter how you work that tap in there, there's going to be channeling. I've found that no tap = no channeling. From seeing the results of the tap I'm surprised that it hasn't yet been treated as an absolute faux pas. Maybe I'm full of it? This is consistent over 3 machines.. mid level commercials and a cheap home machine. I've tried all sorts -- from love taps to bitch smacks, so I know I'm not beating up the puck.


discuss
Tapping the PF on the countertop settles the grains in the basket. Tap before tamp.

Despite all of the ritualistic observances (*) attendant upon it, tamping is unnecessary. You can pull an excellent shot with no tamp whatsoever
  • if you have a good grinder capable of making micro-adjustments to the granularity
  • if you have not overdosed or underdosed
  • if the grains are both well distributed and well-settled in the basket
  • if you give the grains time to swell as they take on water during the preinfusion stage
  • and if your coffee is freshly roasted, i.e. within the past ~7 days give or take a couple of days (or was placed in the freezer while fresh and has been kept there in an airtight container)
Side-channeling can result from a heavy tamp and/or overdosing, either of which can cause the grains in the basket to become too compacted.

Regards
Timo
(*) These began in the New World.

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HB
Admin

#7: Post by HB »

timo888 wrote:Despite all of the ritualistic observances attendant upon it, tamping is unnecessary. You can pull an excellent shot with no tamp whatsoever
You believe this is true for all espresso machines? I haven't given it enough effort to form an opinion, but a quick test on the Elektra Semiautomatica and Vibiemme Domobar Super wasn't promising. It worked quite nicely on the Ponte Vecchio Lusso.
Dan Kehn

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timo888

#8: Post by timo888 »

If the machine is capable of a several-second preinfusion at very low pressure ( ~ 2 bar) and does not exceed 9 bars, there should be no need to tamp as long as the other requirements I listed above are satisfied.

IMO, moderately dosing and then evenly distributing and settling the grains in the basket together are more important than the tamp. ( I use a very light 1# tamp). I don't go so far as to stir the basket contents with pins or needles or paper clips, but I do use the edge of the spoon handle to distribute the grains and then the Chicago chop followed by a thump thump thump on the counter to settle the basket contents.

Regards
Timo

P.S. And I use one or two pulls on the MCF's doser paddle, depending upon whether I'm pulling a single or a double, not the thwack-thwack-thwack method.

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JonR10

#9: Post by JonR10 »

I'll tap and rotate the basket as it fills (on the doserless grinder), and I may tap to updose (after WDT and before levelling). Once I start to tamp I am careful not to tap or knock the basket because it introduces an opportunity to dislodge or fracture the puck. I generally tamp straight down with no twist or polishing.

After tamping I wipe the rim with my finger to clean the seal area, and then (mostly from habit) I invert the portafilter over the knockbox to drop out any very loose coffee grounds.

But I do not believe that there are any taste effects from stray grounds on the PF wall above the puck or other tiny amounts of loose grounds above the puck....at least nothing I can taste myself.

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HB
Admin

#10: Post by HB »

timo888 wrote:If the machine is capable of a several-second preinfusion at very low pressure ( ~ 2 bar) and does not exceed 9 bars, there should be no need to tamp as long as the other requirements I listed above are satisfied.
That eliminates every pump espresso machine I can think of. Have you tried the zero tamp approach with anything besides a lever? FWIW, I think the Astra Gourmet designer advocates no tamp for his equipment because the dispersion block protrudes deeper into the basket to "auto tamp" the puck on lock in.
timo888 wrote:IMO, moderately dosing and then evenly distributing and settling the grains in the basket together are more important than the tamp. ( I use a very light 1# tamp).
I agree, the tamp is at the bottom of my list of critical success factors.
Dan Kehn