If you've got a tamper like the RB convex american base, with the milder, shallower curve to the bottom, what do you do about the sides of the PF?

Do the sides take care of themselves with a good center tamp? Or if side tamps are needed, is the tamper still best held perpendicular to the PF as for the main tamp, or can you tilt, cant, the tamper into the 4 poles fairly gently and get a better pack?

Same question with the RB Euro base, deeper curvature: what is good to do for a well-packed side?

Greg

Dan,

This is a side note. I have found that the best usage of the Macap Auto Tamper is using Staub. I'm surprised its designer did not bring it up. The 56.5 mm piston is just perfect for it. I could never get better Staub tamps hand tamping. But that of course has nothing to do with the experiment at hand .

buzzword wrote:Do the sides take care of themselves with a good center tamp? Or if side tamps are needed, is the tamper still best held perpendicular to the PF as for the main tamp, or can you tilt, cant, the tamper into the 4 poles fairly gently and get a better pack?

I use Staub to tamp, and rarely ever see any channeling. Staub eliminates the need to tap the side of the P/F, which may cause channeling. But to answer your specific question, in a recent jam session with Ken Nye, I noticed that he is experimenting with a new move to tuck in the sides. He rotates the edges of the tamper around the rim after the tamp. I have not experimented with that method.

HB wrote:Actually I mentioned the Staub tamp and the problems the portafilter rest presents. For example, the Cimbali portafilter has a perfectly flat bottom (good), but wide spout (bad). Even with the spout removed, the fork isn't deep enough to allow for tamping the "south" Staub.

I've stopped tamping into the P/F. Not because of problems with the Macap, but because I do not see any advantage doing it in a home environment. I tamp directly into the basket. As to the Macap, I bought a small 1/8" thick stainless steel plate and I rest it on the top of the fork. I put my tamping mat on it, the basket on top of the mat and tamp.

I still tamp by hand every other week, just to keep my tamping skill limber.

BTW, for weeks now I have been trying in vain to work "nutating motion" into casual conversation.

Now, aren't you happy we've had this discussion

In my opinion, tamping is perhaps the most over-emphasized of all techniques.

There are two goals when tamping.
1 - preserve distribution,
2 - create sufficient resistance to water pressure.

It seems to me that many people attempt to use complicated tamping techniques to address deficiencies in other techniques (namely dosing and distribution).

With the correct sized tamper, I've seen no increase in channeling when simply tamping "in the center" over any complicated tamping method and, in fact, find far greater consistency in the extraction (flow, volume) when using the "standard" tamp style.

I'm gonna have to go ahead and agree with Malachi here. Dosing and distribution are probably the most important factors in preparing for your espresso extraction. While the tamp pressure and technique do matter to some degree if your coffee is not properly ground, dosed and distributed in the portafilter basket the technique is all for nothing.

We all should know what a properly dosed basket feels like versus not dosing enough or even dosing too much, that is the key. On my EPNW tamper I see little to none of the tamp piston's vertical sides when tamping and polishing. Below is a hastily illustrated diagram of what I mean.

I appreciate the attention to the question. Since I really am new and don't know anything, I'm caught between shutting up on the one hand and saying things un-useful and lowering the s/n of the site.

Dan wrote:

Your question reminds me of an exchange with the Macap auto-tamper product designer at the SCAA conference.

We were discussing some potential improvements to their products. I commented on the auto-tamper, which comes with a 56.5mm and 53mm piston. A gap of over a millimeter all away around? Why not make the disk larger to knock down the stray grinds during the compression stroke and better seal the edges to prevent side channeling? He claimed that compressing all the way to the edge was unnecessary and a larger disk wouldn't reduce channeling one wit.

Seems like unless the fit of the tamper in the PF is perfect, there will be diminished compression on the edge somewhere. I don't have any sense of how much difference that would make.

For a flat tamper, I picture the compression/density increasing, around the circumference, in basically linear fashion, from the bottom edge of the tamper to somewhere on the side of the PF; a conical section of higher density, with the top of the cone almost exactly the same size as the tamper. That would, I'd think, leave some less-compressed coffee in a circumferal wedge (thickest end on the surface of the cake). A picture would be good.

The apparent best tamp would have the minimum wedge of less-compressed coffee.

A convex tamper would create a different pressure configuration, maybe a buldging conical section, because the tamper exerts true lateral pressure near the top of the coffee, where the flat tamper exerts a kind of inferential lateral pressure only. Added lateral pressure should mean increased compression to the circumference.

Then malachi wrote:

In my opinion, tamping is perhaps the most over-emphasized of all techniques.

There are two goals when tamping.
1 - preserve distribution,
2 - create sufficient resistance to water pressure.

So even if my intuition were somewhat true, malachi's words say that it just doesn't matter much, and I believe him.

In so far though as good extraction requires consistent compression, the question of "what happens with a center-only tamp" seems to partition a useful component of the question space.

So I'm glad you're going to exercise the Macap, Dan. Thank you.

I've been using the MACAP auto tamp thing for a while as we sell it in the UK.

Great in theory but we've asked for a few modifications - wider tamper, convex base, a decent clean smooth base to the tamper (at the moment it collects A LOT of coffee grounds) and for the tamper to be fixed and not swivel.

I like the idea - and it's very close to being a useful tool.

Although I feel that tamping technique is very important, it is all for naught if distribution is poor. For the past year or so, I have been focusing a lot of attention on distribution techniques. I feel that this is one of the most overlooked areas of shot prep. Since moving over to triple baskets the need for proper distribution has become even more important. I have also found that different types of group heads require different methods of distribution.

Once you have achieved proper distribution technique for your machine and basket size, various tamping techniques can be experimented with to help achieve the best extraction. Tamping almost becomes a type of "fine tuning". It can actually be alot of fun to see how minor changes in tamp style can affect the shot.

I always remind people that the 30 or so pounds of pressure that are applied during tamp are only a fraction of the force (9bar) that the puck will encounter during extraction. Tamping only helps the puck to receive this force evenly.

The specifics of tamp technique only come into play once you are sure that grind and distribution are in order.

Abe Carmeli wrote:I've stopped tamping into the P/F. Not because of problems with the Macap, but because I do not see any advantage doing it in a home environment.

When this technique was brought up on the Brewtus group, we tried it but didn't like it because it was a pain to knock out the puck (the basket comes too).

But, as Chris has discussed, it's important to rotate the portafilter when dosing. We have a Mazzer Mini-E (no doser, just a funnel), and I find that if I just let it fill the portafilter straight that I get blonding early on the back half -- and if it's a triple basket, channeling too.

I've mostly stuck to doubles, since even rotating the portafilter doesn't quite do it since I can't rotate it 360.

But, combining these two bits of advice, I tried filling the basket out of the portafilter again, this time constantly spinning it. And, also using advice from Chris, tapping the basket on the forks to settle the grounds -- and this I did periodically a couple times during the fill. Wonder of wonders, the back-half blonding was completely eliminated. And even with the triple basket. And no channeling.

Thanks muchly! Alas, my partner-in-espresso doesn't like leaving the spring out, so I'll either have to convince him of the advantage or get another naked portafilter. Heh.

Michelle

When this technique was brought up on the Brewtus group, we tried it but didn't like it because it was a pain to knock out the puck (the basket comes too).

Michelle,

Get a ridgeless basket, and you can leave the spring in.

I got a gently convex (US curve) tamper friday from Reg Barber and things are much better for me. Adjusting the grind is suddenly a pressing matter, cause the pours are generally centered (in the bottomless) and steady.

The nutating motion is mentioned as something for flat tampers:

Stronger baristas may use heavier tamps, while some use a nutating motion (rolling the tamper in a motion like a flipped coin settling) to accentuate the pressure towards the edges of the basket. An alternative to the nutating motion is using a convexly curved tamper, which accomplishes the same thing.

The nutating roll seems natural with the convex, the roll will be over a wider area (like the rings on Saturn) than with the flat , and not so acute against the very side; the convex is not very well suited for NSWE side-scraping tamping, and nutation seems like it might work very nicely after tapping; it feels even and natural. I'm glad I got the short handle without the ball end, the low control feels good.

I've got to say again, in keeping with malachi's counsel on s/n ratio, that I'm just talking, and know really nothing.

Edit: A flat tamper can't hit precisely on the edge with a nutating motion because the slope from the rim of the PF, along the side of the tamper base, to the point where it creates a circle on the coffee near the side, can not be on the side; there's an offset like (diameter of circle of max nutating pressure) = (.97 * PF diameter) or something like that.

A concavity would put the direct perpendicular pressure right at the edge of the tamper at the time of the main tamp, so a perfect-fit concave tamper would create a pressure circle right against the sides of the PF.

Nutating with a flat would seem to promote scraping across the surface as the tamper tried to snug up into the pf circum.

I understand that the tamp has a modest responsibility, but the view inside of a PF is exercising my brain.