Some thoughts on tamping (tamping twaddle, part deux)

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#1: Post by RapidCoffee »

There have been a number of recent posts on H-B, asking about tamper issues such as size and preheating. My thoughts on tamping run along these lines:

1. Get a good tamper, it's worth it. You'll enjoy using a fine tool more than the ill-fitting POS plastic tamper that is included with most espresso machines. But don't assume your espresso will be any better with an $80 Reg Barber than a disk of plastic.

2. Don't obsess about piston shape. Convex tampers seem to be slightly more forgiving, but it's a subtle effect. I don't really care (or even notice) if I use a flat or convex piston any more.

3. Don't bother getting an exact piston fit to your basket. For one thing, baskets vary in size, even from the same manufacturer. An exact fit to one basket may cause the tamper to bind in another basket. For another, it just doesn't matter if your tamper is 51.1mm or 51.2mm (see pictures below).

4. Preheat your cups, not your tamper. Preheating the tamper has to be one of the silliest myths I've heard, in a hobby that's chock full of silly myths. :P

5. Do strive for a level tamp. Judging the distance from the top of the tamp around the rim of the basket with your fingertips can help. It may be useful to start with a light-pressure level tamp, followed by a full-pressure tamp. It's easier to achieve a level tamp when the surface of the puck is pre-levelled.

6. Do not worry about tamping to exactly 30 pounds. You'll do fine with almost any consistent tamping pressure. Clicking tampers (like the Espro) are good for a one-time reality check; most people tamp harder than they think. I prefer non-clicking tampers.

7. Do not tap the tamped puck. This odd habit has no benefit whatsoever on the extraction, and I'm amazed to see people still tapping away. Tapping can break the seal between the tamped puck and the basket, and is probably the best way to increase the likelihood of channeling.

8. A no-pressure twirl to "polish" the puck probably does no harm, but also does no good. Polish away if you want, just be sure not to put any pressure on the tamper.

9. Do get the best grinder you can afford. This is far more important than the tamper.

10. Do pay attention to dose. Correct, consistent dosing is far more important than tamping.

11. Do pay attention to distribution. An even distribution of coffee grinds is far more important than tamping.

In Chris Tacy's words, the purpose of the tamp is to preserve the distribution. Poor distribution leads to uneven extractions, and this cannot be cured by tamping.

12. One possible exception to rule 11: a nutating tamp may help correct for distribution flaws. But it's better to get the distribution right in the first place.

Inspired by Dan and Ian on the Tamping Twaddle thread, I compared pours with a 58mm tamper and a 51mm tamper on my 58mm Vetrano. Some folks (including me) were surprised by the results. After all, nobody in their right mind would recommend using a 51mm tamper in a 58mm basket. So let's try it again, under more realistic circumstances. How about a tamper that's just a little bit off in diameter? On a machine without the preinfusing E61 grouphead?

Today I tested 51mm and 53mm Bumper tamps on my 53mm Spaziale S1 (original version). This machine has a rotary pump and no preinfusion, which means a fairly rapid pressure ramp up. As you can see, the 53mm tamp fits the double basket quite closely, whereas the 51mm tamp is (surprise!) 2mm off.

53mm tamper on left, 51mm tamper on right

Tamped pucks:

15g doses of Klatch Belle Espresso


both pours looked great

And in the cup:

I couldn't taste any difference between the shots

So there really is no reason to worry about a tamper that's off by 0.1mm. You can be off by 20X that amount, and pull one fine shot after another.

OK, let the fun begin...

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#2: Post by AndyS »

RapidCoffee wrote: My thoughts on tamping run along these lines:
My thoughts run along slightly different lines....
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#3: Post by RapidCoffee (original poster) »

I defer to the master. Even in 2001, Andy was far ahead of us now:
Just recently I found that the Reg Barber tamper I previously used was unsatisfactory. Even though I could maintain the temperature of the tamper at 68.0F (so as not to alter the temp of the top surface of the coffee puck), I could not adequately control the moisture content of the wooden handle. This led to all kinds of humidity errors. Since switching to an all-aluminum Vivace Ergo Tamper, this problem is solved.

My Illy espresso cups have been carefully hand-selected to find individual cups that exhibit variations in wall thickness of no more than 0.002" (0.05mm). The cups are, of course, kept in a PID-controlled water bath at 162.5F.

There was just one last nagging inconsistency that inhibited by experience of true espresso bliss. I found that an annoying variability of the temperature of my tongue just prior to sipping the espresso was interfering with my ability to make subtle taste distinctions. I now submerge my tongue and lips in a distilled water bath which is PID-controlled at 98.6F for the duration of the 30 second shot. As the shot finishes, I remove my tongue from the distilled water, quickly bring the tiny cup to my lips, and experience the joy that only a perfect espresso shot can produce.
I prefer a light saline solution for my tongue bath. :lol:

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#4: Post by malachi »

The left shot actually looks better (see the less even extraction illustrated in the flow).
What's in the cup is what matters.

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#5: Post by cafeIKE »

Oh, come on, Chris... you can have greater differences with the same tamper... even with weighed, WDT'd, dubl-futzed doses.

John got it right :
RapidCoffee wrote:I couldn't taste any difference between the shots

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#6: Post by shadowfax »

Seems like the next step is 53 mm vs. 58 mm on Vetrano, or have you done that as well?
Nicholas Lundgaard

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#7: Post by Beezer »

This thread should be mandatory reading to all people who visit this site. Bravo!
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#8: Post by jpreiser »

To my still-in-training eye, the left shot looks better even though they both look good.

I'm still working on getting consistent tiger striping on my naked shots. I seem to be getting channeling on a side (not always the same side). My grinder is probably due for new burrs (about 3yrs old out of a cafe) but still get decent extraction times. Beyond that - and more likely - I'm thinking my distribution and tamping technique needs some work.

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#9: Post by dsc »


I know that you couldn't really tell a difference taste-wise, but how did the shots start? Was there any evidence of side channeling with the smaller tamper (like a visible donut extraction)?


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#10: Post by RapidCoffee (original poster) »

dsc wrote:I know that you couldn't really tell a difference taste-wise, but how did the shots start? Was there any evidence of side channeling with the smaller tamper (like a visible donut extraction)?
None whatsoever. Both pours looked equally good throughout the extraction. Keep in mind that those pix were taken with a handheld P&S digital camera in idiot mode (auto setting with no user control over the exposure), and on-camera flash for lighting. I made no particular effort to sync the exposures to a specific time in the pour. If you've used a bottomless PF, you're aware that the espresso flow is never completely uniform.

You guys must have better eyes than me. :shock: I'd be hard pressed to pick one of the nekkid pour pix over the other. The one on the right looks slightly lighter in color, but this could easily be an artifact of lighting (note the more intense highlight on the leading edge of the PF) or timing (taken a few seconds later in the pour).