loader image
January 30, 2017 /
For a Good Puck

Have you ever had your coffee-making analysed by someone who sticks their fingers in your spent pucks?

Have you ever decided not to use a particular espresso basket or recipe because the grinds are sloppy after brewing?

If you’ve answered yes to any of these, this post is for you.

You can stop worrying about sloppy, soggy, watery pucks because there’s nothing wrong!

Brewing espresso requires water. This water comes at the coffee from above: through the boiler, group head and finally shower screen before it drops onto the grinds. When you engage the pump, this water fills up the space between the coffee and shower screen, then starts to enter and move through the coffee.

At this stage, there’s water everywhere: above the coffee, within the coffee and below the coffee. When you stop the pump, a valve back inside the machine opens up to release the pressure. Water doesn’t really compress under pressure so there’s not much that escapes at that point. Instead of escaping the group head, it just sits on top of and within the coffee grinds. There’s no pressure to force it out of the basket, there’s nothing to push it up and out of the group head. It’s just hanging in the basket with the coffee.

If you pull the handle out really quickly post-extraction you’ll find a puddle of water that’s slowly lowering into the coffee grinds. After a few seconds the coffee has absorbed all of the water.

The larger the gap between your coffee grinds and the shower screen (headspace), the more water there is. The more water there is, the wetter and sloppier your coffee grinds will be.

If there’s less coffee and more water, it’ll be wetter.

If there’s more coffee and less water, it’ll be dryer.

VST baskets (which I highly recommend) are taller than most. This is a good thing because it reduces the chances of your coffee grinds butting up against the shower screen. If your coffee grinds touch the shower screen, your extraction will be less even. There should be a gap between the screen and coffee grinds to allow water to flow evenly. A wet puck is a far lesser evil than an uneven extraction!

I’m glad we could clear that up.

 

If you have found this useful and want to enjoy delicious coffee with the rest of the community – register for our monthly Superlatives coffee subscription. Or if you just want to keep up with every thing Barista Hustle – sign up to the Newsletter.

Coaching Calendar

Find a course with a BH Certified Coach

April 2020

Mon Tue Wed Thu Fri Sat Sun
1
  • Untitled
  • INA: Barista One
2
  • INA: Percolation
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
  • FR: PERCOLATION
25
  • FR: BARISTA ONE
26
27
28
29
30

News & Updates

Sign-up, Take part and keep in touch!

47
Leave a Reply

Please Login to comment
avatar
  Subscribe  
newest oldest most voted
Notify of
Matt Perger
Guest
Matt Perger

If the coffee is hitting the showerscreen it gets disturbed on insertion, and also relies on the screen to be dispersing water as evenly as the basket (unlikely).

Nick
Guest
Nick

You can try the nickel test. Where you lock in the pf with your normal tamped dose and put a nickel on top. You should be able to lock and unlock it without the nickel imprinting. I find that’s a good starting point.

Adam LeBlanc
Guest
Adam LeBlanc

Correct. You’ll need to check again after you pull a shot to make sure that the grinds aren’t swelling into the screen as well. If they are you’ll need to lower the dose again, and run a few shots to make sure you’re not contacting the screen.

Nick
Guest
Nick

I think headspace is something we should be talking about more, it’s an important contributing factor for an even flow and thus even extraction. On both my lever machines (Strega and Londinium) I find I need to down dose my 18g VST into 16.5-17g territory (with roasts in the city range), otherwise it’s expanding into the shower screen and it’s contributing to a donut extraction.

Cory Andreen
Guest
Cory Andreen

Thank you. Everyone I’ve ever managed to convince of this has been much happier wich the resulting extractions.

John Bower
Guest
John Bower

So, if I dose, disperse, and tamp, then place the portafilter into the group head, I should be able to remove it again not having brewed the espresso, and the puck should be intact with no grounds on the dispersion screen, right? If there are grounds on the dispersion screen, should I lower the dose weight?

James Hoffmann
Guest
James Hoffmann

I’d argue the amount of water ejected through the solenoid valve is reasonable (compared to the total amount of unbrewed water sent towards the coffee). I suppose you could easily catch it and work out how much it is (but I’m not sure this would be particularly useful).

Michael
Guest
Michael

Really interesting Matt. Why does an overfilled puck cause uneven extraction?

Melanie Weldert
Guest
Melanie Weldert

I would love to read more about baskets and wich one is the best one ☺️ Thx.

Old Mate
Guest
Old Mate

For sure. With my e61, 18g VST, IMS screen 16.5g to 17.5g is the optimal dose range for getting full extractions of lighter roasted coffee. Pucks have plenty of room to pre infuse and swell. But if I followed a lot of conventional wisdom, my pucks would be too wet = a true sign of under dosing…. Trying to dose higher always ends up in a less even looking extraction, spouted PF or naked. So the extraction has already started to fall apart well before I have reached my target extraction weight. End up with that classic muddle of under… Read more »

Matt Perger
Guest
Matt Perger

My test exactly!

Matt Perger
Guest
Matt Perger

I don’t know if it’s a variable per se, but it’s definitely important to have.

I do love donuts…

Matt Perger
Guest
Matt Perger

Short answer: VST baskets. Long answer: VST baskets.

Matt Perger
Guest
Matt Perger

I would like to see some numbers on that, but yeah, probably not worth the effort to figure out exactly where that water comes from etc.

Michi
Guest
Michi

i seem to remember reading (don’t know where) that one should see an imprint of the screw holding the shower screen in the spent puck. guess that information isn’t really up to date?

John Bower
Guest
John Bower

I’m going to try this today!

Matt Perger
Guest
Matt Perger

If you have a fixed dose with different extractions it will be wetter or dryer, but most people are just assessing the puck without concern for the rest of the equation.

M Cameron
Guest
M Cameron

Wouldn’t the presence of a “sloppy” or “dry” basket be valuable in assessing the actual coffee dose? There are still many baristas out there not weighing shot doses, either dry or wet, so a sloppy basket would be evidence of an under-dosed basket? A dry basket (I guess with the firm imprint from the shower screen …) pointing to an over-dosed basket? I understand what you’re saying as to the reasons for the water being present on top of the puck after extraction, but I’ve always considered that to be a vital diagnostic clue in helping triage bad shots.

Nick
Guest
Nick

Glad to hear that range is working well for you too. My friends e61 with an 18gvst also does well in the 17g range.

And imho the ideal dose should be based on how the coffee tastes. Too many people overfill their baskets thinking more is better.

Which as a side note/benefit, as I’ve optimized for a super even extraction and taste, the quality of my pucks have gone up. Often a little soupy after the shot, but it soaks in quickly after. Here’s a spent puck:

Roscoe Aquilo-Gordo
Guest
Roscoe Aquilo-Gordo

To me that indicates lack of headspace, which leads me to believe that it is an inefficient brew.

Matt Perger
Guest
Matt Perger

I also believe this is incorrect.

JK
Guest
JK

What I see much more often is what Nick mentioned above – “donut extraction”. Most of the shower screens are convex, leaving more headspace around the edges of the basket and less in the center. When the extraction starts, the coffee swells, releasing CO2 and absorbing water. When overdosing, the coffee in the center of the basket does not have enough room to expand and let the water pass through it. (Creating big density gradient between the center and the sides of the puck.) This causes over-extraction near the edges and under-extraction in the center. Some people argue that this… Read more »

Matt Perger
Guest
Matt Perger

Yeah some screws really poke out. I guess as long as it’s not touching the dry coffee you’re ok!

Robert Cowles
Guest
Robert Cowles

So with a dispersion screen with centre screw (e.g. La Marzocco) you’d have the majority of the puck a few mm further away from the screen than with an E61 type screen? Using the nickel test.

Michi
Guest
Michi

thanks, that was an eye opener! i tightened the grind and lowered the dose and the results are excellent. i guess it’s allright for the puck to show a little dimple from the screw in the showerhead after brewing – right?

coffeespence
Guest
coffeespence

Great post Matt, the coin test is one I use when I’m working on a new machine and one that many people overlook especially in the home espresso market which is where I sit. The good news is that as well as down dosing there are many other ways around this problem. Shower screens are not all built to the same spec and for a small outlay you can pick up a screen that is flat and that doesn’t protrude so much, you can also alter the depth of the gasket in the group which can also help remedy these… Read more »

frustin
Guest
frustin

I have a Rocket Giotto Evo v2 and a Eureka Zenith 65E. I grind 18g of coffee. Having read this and getting wet pucks with my 21g, I tried the 18g basket today in my bottomless pf. Mistake. It’s totally not dialed in for it after using the 21g basket. I have no time to dial in before going to work. The gap between the shower screen and grind obviously makes a difference. With the 21g I get a pour after 8secs. When I tried the 18g (twice, thinking that I’d tamped to hard with the first one), I got… Read more »

Matt Perger
Guest
Matt Perger

I choose the amount of coffee I want to make, which informs the dose of coffee I need to use. Then I choose a basket that is made for that dose +/- 1g

Peter Yock
Guest
Peter Yock

How do you decide the best size of your VST basket Matt Perger? Since there are quite a few options.

Matt Riney
Guest
Matt Riney

Another thought provoking post.

My question is this: what, if any, difference does tamper style (e.g. flat vs convex) have on evenness of espresso extraction.

I’ve noticed with naked portafilters that my shots seem to sidewall channel more often with a flat tamper, while juicing up more evenly with a convex tamper. My flavor preference, however, still leans toward flat tampers being more even and delicious.

Any thoughts on this would be greatly appreciated.

Peter Yock
Guest
Peter Yock

Can you point to a handy chart (or anything similar) that guides amount of ground coffee per grams compared to mL of espresso?

Chris Bennett
Guest
Chris Bennett

Don’t worry about the CO2 it will go straight into solution at the pressure inside the puck. When it hits the bottom of the PF it will come out of solution and froth up making your crema (Just like coke..)
I’d bet that having space over the puck will mean a more even pressure distribution over the top of the puck. Having the coffee grounds up to the screen may(depending on machine) lead to an uneven pressure on the top of the puck which may promote channeling.

Espresso Recipes: Analyzing Dose - Matt Perger
Guest
Espresso Recipes: Analyzing Dose - Matt Perger

[…] Your dose should never sit so high in the basket that it touches the shower screen when dry. If you insert and remove a dosed portafilter, and can see that it touched the shower screen, you need to reduce your dose. In this case, a higher dose won’t let you make more espresso, it will just become a less efficient and more uneven extraction. At the other end of this scale, if your pucks are quite wet and sloppy after an extraction, this doesn’t mean that the shot was bad – it just means that there’s a lot of… Read more »

sluflyer06
Guest
sluflyer06

What about IMS?

Matt Perger
Guest
Matt Perger

Nothing right now, but I would begin using scales and grams for measuring your espresso, rather than mls. Crucial!

Visnjei Roland
Guest
Visnjei Roland

Hello Matt. What do you think about IMS baskets? I just ordered 2 of them, one with 18 g and one with 20 g. I tried both, with lighter roasted and with darker roasted coffee too, but if i dosed 18 and 20 gramms, the pucks were sooo sloppy, they did not come out in one piece, but in a lot of watery pieces, and about 3-4 gramms stayed in the portafilter. To get a puck which comes out in one piece, but still very watery, i had to use 20 g and 23 g. :/ I tried to dial… Read more »

Andy Krista
Guest
Andy Krista

I may be in a bit late here, but I’m curious to know what could case/how to mitigate pucks getting stuck to shower screens. I’ve had this happen a bit with Strada EP and Linea PB’s in the last year and have noticed it could be due to the following variables – bean density, grinding too fine or dosing too low, pressure profiling (on Strada), and (mostly) headroom between the group gasket and shower screen. The only method I’ve found to mitigate this is blipping before pulling out portafilters which, in a busy cafe will result in mess or bottlenecks… Read more »

Tohenk2
Guest
Tohenk2

I think the total amount of holes on the botom and their diameter also varies between the 18 and the 21 gram baskets.

DF
Guest
DF

My thought/ question is how much of the “sloppy” puck vs “dry” puck is due to the longer shot times we’re pulling now a days vs the days of the 20 sec shot? To achieve the slower shot times we’re grinding more finely and creating more of a restriction in the basket with our coffee. The restriction stays even after you’re done brewing, causing some water to remain on top of the puck. I usually attribute it to pouring liquid through gravel vs through sand. It will eventually pass, it just takes longer to do so. Side note- some grumpy… Read more »

DF
Guest
DF

I’d agree with this comment. Think if the head space as a spring of sorts. The water being dispensed from your screen isn’t being dispensed totally evenly over the entire puck. With head space, that space fills with water and once it’s become full it then applies pressure to the puck. The water finds the path of least resistance, and travels through there. With very little head space the water is more directly applied to the puck, therefore causing an unequal amount of water to be applied to once section of the puck. With head space the space fills with… Read more »

Matt Perger
Guest
Matt Perger

Hey mate 🙂

Read my post on sloppy pucks, and also get some VST baskets. You’ll be right in no time!

Christopher Alan Scott
Guest
Christopher Alan Scott

Thank you. This is a difficult concept to explain. I’ll be citing this post often.

Cheers!

Matt Perger
Guest
Matt Perger

I think the roasting is the culprit here.

Visnjei Roland
Guest
Visnjei Roland

I tried the basket at my workplace, with an other coffee. Water has completly gone. It seems that the coffee i tried before was too old. But i still struggle with underextraction. I use a yirgacheffe now, a medium roasted one. 18 g in, 36 g out, 29 s. Sour. Just sour. And also watery. Finer grind, a little bigger body, but not enough. And still sour. Almost the same. Finer grind. Finer grind finer grind. Still sour, but becones bitter also. Back to where it was not bitter. 18 g in, 40 g out. Better but still too sour.… Read more »

상태 좋은 커피 퍽이란? | 위키커피 (WIKI COFFEE)
Guest
상태 좋은 커피 퍽이란? | 위키커피 (WIKI COFFEE)

[…] 기사 인용 출처: https://baristahustle.com/for-a-good-puck/ […]

Jura Impressa S9: The Coffee Machine That's Waiting for You
Guest
Jura Impressa S9: The Coffee Machine That's Waiting for You

[…] hot water for tea, or hot milk for hot chocolate. A high capacity water tank, bean hopper, dregs/pucks box and drip tray mean less time keeping an eye on the […]

breville vs delonghi
Guest
breville vs delonghi

thanks for the information

Copyright © 2019 Barista Hustle, All Rights Reserved!

You have Successfully Subscribed!