The Myth of the Tamp and Tamper? - Page 4

#31: Post by **aecletec** » May 17th, 2016, 7:55 am

Nutation and tamp pressure are really quite different things.

#32: Post by **JimF** » May 17th, 2016, 9:15 am

Agreed, but in the referenced pdf the finding was that both no tamping or flat tamping at any pressure had no observable effect on the resulting shot. All the shots in the pdf appear to have about the same volume. The first test was a specific example of a flat tamp at fairly light pressure, and it produced a very bad, poorly controlled extraction, with almost 3x the desired volume.

The second test differed only by tamping technique, and was included as a control (although my technique let me down this morning).

#33: Post by ds » May 17th, 2016, 9:24 am

Of course tamp and tamper matter on any machine. Water is not solid matter like stainless steel so saying it provides same type of compression as stainless steel over ground coffee is inaccurate. Water is fluid and coffee is porous. Water also seeks path of least resistance to flow through. Un-tamped bed of coffee in basket has numerous veins of and rivers of empty space through them and water will find its way to flow through since it seeks path of least resistance. This will lead to under-extraction and faster shot. Tamping collapses these pockets in coffee bed forcing water to find way through coffee more evenly thus forcing even extraction.

#34: Post by **JimF** » May 17th, 2016, 11:41 am

Since I ham-handed my experimental control, I did a third shot with the same grind, beans, dose, etc., but with a better execution of my usual tamp, measured to 30 lbs +/- .5 lb

Result: 30.7 g extracted. Taste: rich, buttery, chocolatey, with balanced sweet-bittersweet flavors.

So the 83g extraction of experiment 1 was not due to the grind, and the tamp wasn't so loose in that experiment that there would be air gaps, either.

I don't doubt the findings reported in the pdf, but I don't think the conclusion is correct because I can't reproduce their results on my equipment. Perhaps a highly consistent grind, a high precision basket, pre-infusion, carefully controlled temperature, and maybe other factors all combine to make the tamp insignificant in a commercial setup.

#35: Post by **MCALheaven** » May 17th, 2016, 4:02 pm

aecletec wrote:Semantics is everything in scientific writing. They did address the curved tamper.
Are you upset that you were laughing at yourself?

They did not adequately address curved tampers. That was what was so funny. To go to such great lengths to sound knowledgable and be so full of crap. Guess you just like the BS more than I do.

#36: Post by **pcrussell50** » May 17th, 2016, 4:41 pm

I have a ridiculously curved, 49mm tamper for my 49mm lever baskets, (of course, I also have a proper tamper). But every single time I use that curved tamper and then pull a shot, the top of the puck comes out flat. That is telling me that the pressures of extraction are much greater than the tamped puck's ability to withstand such pressure.

I don't think tamping is neccessarily meant to close channels, or vertical paths for water to escape. Channels are made, or not made, when the pressure hits the puck. I think tamping is a final polish, to collapse air pockets and make things as level and even as possible before the real pressure hits. Once the real pressure hits the puck, it is crushed under that pressure and what is happening during the 130psi, is what is called "cake filtration", (look it up), in which the 130 psi extraction pressure of the water is mashing the puck down a LOT harder than you can with your tamp, and those crushed grinds under that pressure are what is causing the resistance to flow. If you don't tamp at all, the grinds will be crushed just the same, and to an identical degree. It's just that when the pressure hits the puck, if it isn't level, it the water may make a channel.

-Peter

#37: Post by **aecletec** » May 17th, 2016, 5:24 pm

MCALheaven wrote:They did not adequately address curved tampers. That was what was so funny. To go to such great lengths to sound knowledgable and be so full of crap. Guess you just like the BS more than I do.

Do you have any substantive criticisms of the article and their supposed negative criticisms of curved tampers?

May 17th, 2016, 8:59 pm

There are believers who do not believe data.

The placebo is one of the most effective treatments in all medicine, as savvy physicians have long known. So long as they do no harm, they are good.

Placebo: late 18th century: from Latin, literally 'I shall please,' from placere 'to please.'

The good news I take away from all of this is: precise tamp force will not hurt, nor will most tampers of any shape, material, heft and curvature. The higher the price the more pleasing.

#39: Post by **MCALheaven** » May 17th, 2016, 9:11 pm

aecletec wrote:Do you have any substantive criticisms of the article and their supposed negative criticisms of curved tampers?

I do not need to defend my opinion of this article. Hopefully you can let it go. I would also like to apologize to everyone here who has written useful and interesting posts about tamping. Thanks for those.

May 17th, 2016, 9:37 pm

I agree, this thread is great. Links to other hard-ish data on tamp and tampers would be totally useful. Let the data free.