Why tap the portafilter?

[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]

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

[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.

[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]

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.

[timo888]

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.

[HB]

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.

[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.

[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.

[HB]

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.

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.

[timo888]

Have you tried the zero tamp approach with anything besides a lever?

I don't own any other machines, but there's a shop on my way to work that has a Nuova Simonelli two-group. The shop's grind is quite fine and fluffy and doesn't need anything more than a very light leveling tamp. On a few occasions, I've asked the barista there not to tamp. One of them really puts some shoulder muscle into his tamps, and spends very little effort on distribution. He just presses the tamper down on the heaped mound. His untamped shots are tasty.

There used to be a woman barista there who would distribute with her pinky very carefully and thoroughly and then simply place the tamper in the basket and give it a couple of spins; her shots were good.

But the espresso made with the muscle-tamp approach channel badly. I would always ask him for an untamped shot, if it weren't for the fact that he is such a great believer in the power of the tamp and regards me as anathema for asking him to forego the main hierophantic element of his ritual bean sacrifice.

I've switched to mochas. He is not one to skimp on the whipped cream and chocolate syrup.

Regards
Timo

[wildlyesoteric]

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 (?)

Okay, not that tap. I'm talking about the intermediary tap between a soft and hard tamp where you tap the PF with the tamper as is common practice. FWIW I find myself giving the PF a rap (not a tap, now!) on the counter to settle the grounds, this yields better results for me (I left it out in the above sequence). I can't possibly imagine air being anywhere in the puck after a 45lb tamp -- I think it's all about distribution, let's call it 3-D distribution.


edit/condense:
When I see a 1lb tamp at WBC I'll take a harder look at it, until then I'll leave it to the Italians.

edit:
After reading about the no-tamp requests. I have a two-group Nuova Simonelli at work. For thoroughness I'll try out the tamper-weight tamp a couple times. I expect that the grind will need to change, as was the case the last time I tried it.

[HB]

I don't own any other machines, but there's a shop on my way to work that has a Nuova Simonelli two-group. The shop's grind is quite fine and fluffy and doesn't need anything more than a very light leveling tamp.

Indeed, Counter Culture had the Aurelia in for evaluation and it was a forgiving group (more info). They elaborate on their "soft infusion" design on their website:

All our units facilitate an industry-leading preinfusion chamber above the grouphead. The Aurelia not only uses our patented, single preinfusion technology, but also provides a second, inline "pressure dropping" mechanism located before the heat exchanger. These "double" features allow the 9 bar needed to produce an espresso to drop to 2 bar, presoaking the grounds and then evenly builds pressure back to the needed 9 bar. This process allows for more crema, more aromas to be extracted while also lowering employee's possible tamping/grinding errors.

Evidently your observation about 2 bar preinfusion holds for levers and the Aurelia.

[timo888]

When I see a 1lb tamp at WBC I'll take a harder look at it, until then I'll leave it to the Italians.

Si, lasciamo a quelli dannati barbari faccialo

edit:
After reading about the no-tamp requests. I have a two-group Nuova Simonelli at work. For thoroughness I'll try out the tamper-weight tamp a couple times. I expect that the grind will need to change, as was the case the last time I tried it.

Bravo

Timo

[wildlyesoteric]

Evidently your observation about 2 bar preinfusion holds for levers and the Aurelia.

That's funny about the Aurelia being a forgiving machine. I had originally written in the last post that the Program VIP I work on is pretty unforgiving. It seems that there's a solid ramp-up to full pressure. I'll check the specs and see if there's info on preinfusion.

[Kaffee Bitte]

Tapping the pf with the tamper or anything else after tamping is just going to cause problems.

As to the light tamp on pump machines. I have worked with various commercial machines originally using a fairly standard to hard tamp. After a while I started trying to lessen my tamp because I was worried about joint injury later in life. I have tried the no tamp timo is speaking of on an Astoria, a La San Marco, and an LM Linea. I never personally was satisfied by the look or the flavor of the no tamp shots. What I finally settled on though would still be considered a light tamp. Finer grind is required without doubt. But the light tamp I use at work now is approximately 10 lbs pressure. Any less and the results are not up to par.

Recently on my lever at home I have been varying the amount of tamp I use. I have been moving away from the extreme light tamp in order to increase my dose a little. I have even tried the gorrila tamp a few times, though I was less than impressed with what came of it. As of now I am settling into ~10-15 lb tamp with a dose between 13-14 grams on my machine. This is more than I can normally fit in the basket with the light tamp.

[Spironski]

I can't possibly imagine air being anywhere in the puck after a 45lb tamp -- I think it's all about distribution, let's call it 3-D distribution

Oh yes I can. As I discribed with filling my coffee-container; when I fill it with beans to the brim, I could push down hard on the beans, but almost nothing would happen. Only when I "tap' the container, there seems to be space between al those beans and I can pour in some more. There is air between all those beans!

It seems that when you tamp, only the upper half will be compressed. It leaves you with an even compacted surface. Underneath that, grounds will stay a bit "loose'.
When you tap your PF on the counter however, you will settle all the grounds, and make your puck more solid as a whole. I guess 22kg or 15 kg, or even 10 kg after the tapping wouldn't make that big a difference (that is more about the 25 sec. extraction time). It is all about a solid puck without fractures or soft spots (so care-full distribution and tapping).

[Spironski]

When I see a 1lb tamp at WBC I'll take a harder look at it, until then I'll leave it to the Italians.

I have been a couple of times in Italy, and I have never have been served a bad espresso. One was okay, most very good and often they've been superb.

So what is it? is it knowledge? is it passion? They are doing something right down there!

[cannonfodder]

I use to tap for many of the same reasons stated above. It could also have been a case of monkey see monkey do, others did it so it must be good, the mob mentality. After a lot of reflection, I gave up on the mid tamp tap, I even gave up on the mid tamp around a year ago. I do give the portafilter three small thumps on my tamping stand to settle the grounds in the basket, then one tamp, brush off the stray grounds from the basket top and locking lugs and pull my shot.

As far as I can tell, the portafilter tapping serves no useful purpose; in fact it may do more harm than good. The entire reason you tamp is to create an evenly dense puck so the pressurized water flows evenly through the coffee cake. Water will seek the path of least resistance so any change in density will result in more/less flow through the puck. Tapping on the portafilter could jostle the coffee cake and create a fissure or break the side cohesion with the basket. Both of those will lead to channeling. I have noticed no ill effects from stopping the tamp, tap, tamp ritual and I may have a few less sink shots because of it. The stray grounds on the sides of the basket do no harm.

[wildlyesoteric]

Tried the 1lb flattening tamp today, ended up going of full number on the MDX finer (significant). In the words of Mia from Pulp Fiction, "I say gatDAMN". Great flavourful shot. Different, but very nice; a little more sweetness I found than with a conventional (NA Terms) tamp, at least with the blend used.

That being said, this thread isn't about tamping or not, so that's all out of context.

Anyway, I think the tap should be phased out. I doubt it's doing any good to anybody out there.


Full extractions FTW!