58mm vs 58.5mm tamp

Beginner and pro baristas share tips and tricks for making espresso.
DamianWarS

#1: Post by DamianWarS »

If you had good and consistent puck prep and pulled shots back to back with a 58mm and a 58.5mm tamper what sort practical differences would you expect to see? If it were blind could you tell the difference either visually or with the taste?

User avatar
BaristaBoy E61

#2: Post by BaristaBoy E61 »

I rather doubt any difference would likely be noted - especially with a long, slow preinfusion to 'heal' any puck prep imperfections.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

BaristaBob

#3: Post by BaristaBob »

I suspect all else done well, the 58.5mm tamper will limit the likelihood of the "halo effect". You should, based on theory, get more even penetration of the water through the entire puck since we know water is inherently lazy.
Bob "hello darkness my old friend..I've come to drink you once again"

cmin

#4: Post by cmin »

There can be quite a difference, on my HQ21 58mm tamper is useless, 58.4-58.5 makes a big difference as reg 58 is too small. You'll get donut extractions no matter what prep or slow PI etc you do otherwise, or more channeling as it fits noticeably looser in basket.

User avatar
cafeIKE
Supporter ❤

#5: Post by cafeIKE »

Show us the data.
ER, ml/s, TDS, etc.

User avatar
Jeff
Team HB

#6: Post by Jeff »

I'm somewhat skeptical that a 200-250 micron difference in edge gap can make a big difference when the nominal particle size is somewhere around there as well.

Just to throw a wrench into the machine, there is some belief and supporting evidence that the dreaded "donut extraction" may be a good thing if not excessive. It is theorized that the boundary conditions in the basket tend to disfavor extraction from the grinds against walls of the basket.

User avatar
BaristaBoy E61

#7: Post by BaristaBoy E61 »

A ½mm difference?
Put me in the skeptical column too; I'm just not buying it.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

cmin

#8: Post by cmin »

An HQ21 ridgeless basket, well known you have to use a larger tamper, even years ago other owners said same (and I've had one for 10 years). 58mm will not work, way too small, unless you want donut central extractions and channeling issues like myself and other HQ owners on here experienced years ago with smaller tampers. HQ21s are wide and have depth, I just rechecked with calipers, 59.2mm, a reg 58mm is like a loose noodle in that basket and last time I measured a "58mm" tamper wasn't even 58 but 57 I think. Vst20 basket is about 58.5 with calipers. Have other tampers but years ago I had the tamper dude on ebay, forgot his name, think he was on here also, make me custom base for that basket. Even the normcore (which I think was 58.5 spec'd but with calipers 58.5) fits lil loose but is tight on vst, of which reg "58" is quite loose in vst, now imagine on a HQ21 basket that's literally 59.2mm with calipers, you can jingle a "58" in that basket like a bell and nutate to hearts content and won't do anything, will still channel and donut. I'd rather just tamp and not be irked by awkward flow/color lol.

User avatar
HB
Admin

#9: Post by HB »

Even if a 0.5mm larger tamper base matters, you can always tamp more than once with a 58mm following the so-called "Staub" NSEW tamp method. :)

If someone wants to validate there is/isn't a difference more objectively, it wouldn't be hard to do it blinded. Get two identical baskets with one discreetly marked under the rim. Fill and distribute outside the portafilter, then have a helper tamp both baskets, one with a 58mm tamper, the other with a 58.5mm tamper. Have the helper record the pulls with a bottomless portafilter. Then hand the two cups to the taster. If the difference is significant, it won't take many trials (around 5, according to Jim's A note on comparison tests).

We've done this kind of test for equipment reviews in a group setting. There have been cases where the group expected "A" to win by a large margin and it ended up a tie or "B" winning. For this reason, I treat most assertions of X vs. Y as interesting anecdotal observations if no blind test was done.
Dan Kehn

User avatar
cafeIKE
Supporter ❤

#10: Post by cafeIKE »

Just for grins I got out a 57mm tamper to use alongside the 58.5. The basket is a Triple "Synsesso" that looks quite similar to the PF21.

Whilst I was making an Americano and a latte, the shot start and flow were, as my Gramps was oft to proclaim, "As close as Damn It All is to swearing."

In the 15+ years since the Tamper Roadshow, I've often used different tamper shapes and diameters when pulling sequential shots, not latte or Americano, for guests. NOT ONCE, has a guest ever commented on a taste delta. The ONLY tamper effect I've ever been able to determine was the The Radical Pro which spritzed like crazy.