The world is not flat, but what about your tamper?

[Habit]

Ive done a bit of research on tampers.

I quite like the idea of the Greg Pullman, precision made for my specific basket(size).
Ive even got a design idea for getting one or two cusom made for me.

Any opinions out there?

Im interested in what you think.

Jeff.

[poundy]

Re: The world is not flat, but what about your tam

I like flat.... thats what I have. But I could only (easily) get a convex tamper for my mothers Napoletana, 57mm, so thats what she got, its still better than trying to use the original one on the machine, but in my view its too convex, so that theres too much gap between puck and shower screen in the middle of the handle, and at the edges the puck is against the showerscreen.

[scoota_gal]

Re: The world is not flat, but what about your tam

I have heard that the Pullmans are a very nice tamper. Wouldnt mind one myself!

And I would have thought that flat was better. I prefer it anyway, the rounded ones we have for the commercial machine dont seem so stable when you push down to tamp. Almost like youre about to slip off!

[robusto]

Re: The world is not flat, but what about your tam

Debate has raged about the virtues of both flat and convex tampers, with no aparent conclusion.

Obviously a flat-bottomed tamper will produce an even surface on the puck.

Assuming water pressure from the shower screen is also evenly dispersed, that style would suit that particular machine...

A convex tamper allows more headroom under all but the very edge of the shower screen, allowing the puck to swell more easily with the ingress of water.

But that also means the puck is packed unevenly, more coffee density in the centre, less at the rim.

Water pressure and volume would tend to be greater at the centre because of its proximity to the exit hole of the water. But not entirely. The shower screen screw would block some water at the very centre---where the concave puck is at its densest.

And it gets more complicated....On the Silvia, for instance, under the shower screen theres a nifty disperser designed to radiate the water laterally across the screen to offset the tendency for water to shoot straight down.

That may (a) exacerabate the lack of water pressure in the very centre of the puck (where the puck density is greatest).... and/or (b) compensate for the tendency of the water to shot out from the immediate area surrounding the shower screen screw (again, where the puck density is greatest).

So it really depends on the design for water dispersion. I would think that if the water just shots out with greater force in the centre -- a convex tamper would be more beneficial.

Robusto

[Fresh_Coffee]

Re: The world is not flat, but what about your tam

It doesnt need to be that complicated....!

The convex tamper is in my honest opinion the way to go.

The reason is simple. It most closely follows the *not quite flat* shape of most showerscreens. If you have a flat shower screen, then by all means use a flat faced tamper.

That said and in terms of convex, there are two kinds of "convex". The exaggerated rounded faced tampers that I wouldnt give you 2 cents for as they leave a great big hole in the middle of the puk, and the *gently* convexed type that I like. I use one of these.

After that...its a personal thing like politics and religion!

If you want more info, check out the topic on tampers in this forum somewhere, from last year. Might need to do a bit of searching...it will give you a bit more (interesting but perhaps pointless) information to read with your morning cuppa. As  said up top...it doesnt need to be that complicated.

Check out the tampers somewhere down the page at this link:
http://www.cosmorexcoffee.com.au/appliances.htm

Theyre the type I am using at the moment on my training machine, and they have that nice gentle curved face.

Regardz,
FC.

[mattyj]

Re: The world is not flat, but what about your tam

I use a flat tamp (pullman), but from playing with a naked pf, I really want a slight convex, to match the shower screen. All my shots tend to extract heavily around the edges of the basket, the worst shots are all edges, with no espresso dripping from the centre of the basket.

Ive been able to work around this with the weiss distribution method (check out home-barista ... totally a home-geeky thing, definately not suitable for a cafe), but a convex tamp, IMHO, would suit my shower screen better.

The main thing is distributing the coffee in the basket to an even density, before tamping. Tamping only compacts that density.

[Habit]

Re: The world is not flat, but what about your tam

Aaaah......thats why I like it here so much.

Passionate opinion.

Heartfelt sentiment.

Thanks one and all. I appreciate you offering your thoughts. That gives me more to go on.

Id pretty much drawn the conclusion that the appropriate shape for a tamper would be dictated by the shape of my shower screen and the profile of my filter basket (perhaps equally).

I reckon I know what Im after now.

Jeff.

[Kualityman]

Re: The world is not flat, but what about your tam

Arh robusto, i must thank you for your suggestion re the tamping machine. yes i know these exist in the commercial world but in a domestic situation particularly mine, my wife would throw the thing at me. So thank you for your suggestion but Im looking for a filling device and then of course the tamper. Now to my mind most tampers are flat or as is currently being discussed convex. Fluid dynamics being what they are really do not lend themselves to either of these shapes.
First things first, before buying a tamper check your showerscreen, what shape is it? Concave, flat or convex? If it is concave, my Sunbeam is, then a convex tamper just destroys the water path leading to little crema and low extraction. A flat tamper on the other hand is still not the solution as there is a considerable space above the portafilter. I need a convex tamper. In due course i shall make one and let you know the outcome. In the mean time I tamp using a plastic tamper supplied with the machine only I dont tamp the grind flat. I rotate the tamper applying more pressure to the outer ginds until i have a hill of sorts in the centre. Then I apply a more uniform pressure to the whole. Takes a little practice but not to difficult. I now find that i get a greater extraction. This is demonstrated by the flow going from an 8 to 10 second shot to a 12 second shot without going bitter.
It is my opinion, stress my opinion that flat showerscreens do not help with the fluid dynamics as the water flows though at the line of least resistance which could be anywhere across the screen.
Im essentially saying that the tamper design should be according to your showerscreen.
I am also of the opinion that the smooth surface of the current tampers is also a hinderance, but more on this later.
Are you having fun?
Kualityman

[Habit]

Re: The world is not flat, but what about your tam

Thanks Kualityman,

Im having an absolute ball, in fact, I surmize that if this were any more fun, itd surely be illegal.
Couple things.
Im interested in your thinking re a filling device. I theorize that there are shortcomings in the dispensing with both dosered and doserless grinders. I suspect that agitating the PF (gently beating it against the heel of my palm for example) to ensure even distribution before topping up, settling, leveling and tamping, pretty much overcomes the shortcomings.
I like your theory regarding tamper shape related to showerscreen shape, but I feel the shape(profile) of the filter basket has an impact in the scheme of things (look away FC ). i.e. When you flat tamp, pressure is applied pretty much virtically, IMO, that doesnt mean even pressure through the grind, filter baskets generally have at least a moderate taper toward the bottom. Potentially, that means weve compacted more around the outside at the bottom. That being the case, a convex tamp could help compensate and even up pressure distribution. If the showerscreens convex, great, if not, what then? Find a filter basket with as little taper as possible?!? Then flat tamp if you have a flat showerscreen. Not quite sure how Id propose coping with your concave screen

Then we get to Robustos theory re water distribution from the showerscreen (which I like), and your fluid dynamics.

So, Id like to discuss your philosophy of the physics of liquids in motion as it relates to the artistic endeavour of creating a great cuppa.

Did I mention I like it in this place?

Jeff