Now that I've got your attention.... :grin:

Brady and I decided that this weekend has been kinda slow on BX, so I thought I would generate some controversy. Please consider the following:

We performed an experiment at Counter Culture's Training Center during the Southeast Regional Barista Jam based on an observation made by Brent Hall. He mentioned that the 30 or so pounds of pressure exerted by the barista while tamping the dose in the portafilter was essentially negated due to the extreme pressure placed on the puck during extraction. In other words, your espresso machine has bigger muscles than you. Other than channeling, why bother then? So we tried it, dosing into the portafilter, leveling, and then, skipping the tamp, locking into place and pulling the shot. It worked.

Now, is it consistent? I doubt it, but that would depend on the barista, same as the tamping procedure.

The question that arises in my mind is this: have we given the proper importance to the leveling process, as this is where we deal with clumps and allocating the coffee evenly in the portafilter?

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I think the important part of this is preinfusion. The leveling is not as important if you have dosed evenly throughout the portafilter. When preinfusion occurs the coffee blooms and pushes up evenly then after it blooms 137psi pushes down and voila! a perfect shot!

However, if the shot wasn't dosed evenly channeling will occur, because (I think) the coffee isn't blooming evenly.

I thought it was much easier to pull an un tamped shot off the paddle machines than the button ones.
Interesting... I think one of the main reasons of tamping is to get the puck below the dispersion screen... I have done some experimentation with tamp pressure and I would have to agree that a shot can be pulled with pristine extraction even w/o tamping... I would say that the dose just needs to be distributed evenly and lower than the dispersion screen... leveling and distribution is very important... I think more important than tamping... Cant wait to read the rest of this discussion...
Cheers,
Chris
I should have remembered that, Jonathan. Yes, the paddle-equipped Linea also had naked portafilters that made it especially easy to observe the extraction. The preinfusion angle will have a great deal of bearing on this discussion.
I'm going to agree that the dose would need to be below the dispersion screen. If it isn't, it seems like it would go through a mush and a twist (to use technical terms) when the portafilter goes in. If you're up-dosing, it's going to make it nigh impossible to get them grounds that low. The only solution would be . . . to tamp it.

So we don't want to tamp, but to prevent the dreaded dispersion mush and twist we go ahead and tamp. Problem solved.
I'm going to disagree, the build does not need to be below the basket rim and hence not below the dispersion screen. Yes I've tried it a number of times, all nekkid, all just fine. First saw it done at a trade show over a decade ago.

The caveat is the post shot group tends to be messier than with tamped build.

The purpose of the tamp is to preserve the distribution, it's not actually part of the distribution.



James Spano said:
I'm going to agree that the dose would need to be below the dispersion screen. If it isn't, it seems like it would go through a mush and a twist (to use technical terms) when the portafilter goes in. If you're up-dosing, it's going to make it nigh impossible to get them grounds that low. The only solution would be . . . to tamp it.

So we don't want to tamp, but to prevent the dreaded dispersion mush and twist we go ahead and tamp. Problem solved.
I didn't mean to imply that the tamp was part of the distribution, but that it would prevent unwanted distribution. I implied that the mush and twist would affect the distribution. Mostly the twist, the mush itself is kind of a tamp. But that's cool if you're getting even extraction.

But if the pressure is so great and stronger than my manly muscles, why does it end up so yucky if I don't tamp?

miKe mcKoffee aka Mike McGinness said:
I'm going to disagree, the build does not need to be below the basket rim and hence not below the dispersion screen. Yes I've tried it a number of times, all nekkid, all just fine. First saw it done at a trade show over a decade ago.

The caveat is the post shot group tends to be messier than with tamped build.

The purpose of the tamp is to preserve the distribution, it's not actually part of the distribution.



James Spano said:
I'm going to agree that the dose would need to be below the dispersion screen. If it isn't, it seems like it would go through a mush and a twist (to use technical terms) when the portafilter goes in. If you're up-dosing, it's going to make it nigh impossible to get them grounds that low. The only solution would be . . . to tamp it.

So we don't want to tamp, but to prevent the dreaded dispersion mush and twist we go ahead and tamp. Problem solved.
I'm going to echo a few things already stated. This is something that I've played around with a bit, on both naked and split portafilters.

Yes, the machine will definately apply more pressure through the puck than your puny human arm muscle could even think of.

Yes, preinfusion helps when pulling a shot to "fix" any small errors that you as a barista may have made in your distribution.

Yes, you can get a really tasty shot without tamping.

But not consistantly. And this goes back to the mush and twist. (Love those terms, so I'm co-opting them. With the authors permission I hope).

Tamping acts as a preserver of your distribution. If you have dosed the correct amount and tamped properly, then your puck will not come into contact with the screen and your distribution will be preserved for your pressured infusion. If it comes into contact with the screen, then you've just mucked everything up. Congratulations, your chances of pulling a tasty shot have just decreased.

As baristas, it is to our benefit to control everything that we can in order to make the coffee taste like it is supposed to. So many things about espresso extraction are beyond our control. It is inherently a dynamic and complex process. The more that we can do to put that extraction within our control the better. I firmly believe that tamping is one of those safe-guards, like a PID and preinfusion, that is best to utilize.
Nicely done, Paul.

I was only peripherally involved with the no-tamp experiment that you guys ran at SERJ, but recall it generating some interesting results. The thing that I don't recall is: were the non-tamped shots as tasty as the tamped ones? I know they usually look great, but the ones I've tasted have been lacking.

Interested to continue to hear your thoughts.

b
James raises another question, and I don't think we've answered it. Why does the untamped puck look so muddy and messy, as compared to the tamped puck, if the pressure placed by the group head is the same? Does tamping regulate bloom? Does it affect how dry the puck is afterwards?
Yes, the machine has more muscles than any barista. But, the fact still stands that water will take the path of least resistance (ie channeling.) No matter how well you think you are dosing and leveling your un-tamped puck in the basket, there will be gaps from where the espresso has not settled, creating spots where more water, and therefore more dissolved solids, will pass through the puck in the early stages of shot extraction. Tamping takes out the likely-hood of channeling and the guess work, giving you something that you can for sure say, that shot was evenly distributed and packed and will not have any channeling because i took all the guess work out. Dissolved solids = muddy.

Also when you tamp, you do place more resistance in the basket for the water pressure to combat. So although initially the pressure from the group head should be the same, you are creating an artificial resistance by tamping and only minimal, natural resistance by not tamping. And as far as tamping regulating the bloom, I guess in some sense yes it can help, but as far as keeping the puck dry when extracted, I would think that tamping could also help regulate it because it gives you an aspect of control.

Paul Yates said:
James raises another question, and I don't think we've answered it. Why does the untamped puck look so muddy and messy, as compared to the tamped puck, if the pressure placed by the group head is the same? Does tamping regulate bloom? Does it affect how dry the puck is afterwards?
Take the portafilter out of your machine. Start the machine. Read the pressure gauge. Well, it probably says 9 Bar, but there is currently 0 psi at your head. Without resistance, there is no pressure.

The way to measure post puck pressure is to use a spoutless portafilter with a line pressure gauge screwed onto it. The density of the puck will change the dwell time of the pressure rise.

If the coffee is lightly packed, it will easily allow water flow at less than 1 Bar. The machine has 9 Bar "available" but that's not what's happening in the portafilter.

My experiance is that it tastes better when tamped. But...I've tried it and also been pleasantly surprised.

I'm still a tamper fan.

Paul Yates said:
James raises another question, and I don't think we've answered it. Why does the untamped puck look so muddy and messy, as compared to the tamped puck, if the pressure placed by the group head is the same? Does tamping regulate bloom? Does it affect how dry the puck is afterwards?
For clarity's sake, lets try to be precise when we attribute effects to the different aspects of dose, distribute, settle, level, and tamp. You can properly dose, distribute, settle, and level without tamping. As I recall, channeling was not an issue with the untamped shots, and did not seem to occur at any greater frequency than the tamped shots.

Tamping certainly does effect the extraction in the way Eric described. This is pretty easy to demonstrate observing the change in extraction times as you vary tamp pressure (but not grind or dose).

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