# Group head & grounds



## Hasi (Dec 27, 2017)

Hi people!

Keeping espresso machines neat and clean of left over grounds seems rather obvious and straight forward since everything is easily accessible and, for the most part, visible. Still, it gives me a headache to go after debris that much after each and every shot. To be sure I'm good to pull the next one, I undertake the following procedure:

flush w/o portafilter, stop water

brush group head gasket and shower screen sides (using a hard plastic brush that came with the machine)

flush again, stop water again

insert portafilter and rinse for 10+ seconds

wipe filterbasket and shower screen with a towel

Eqipment-wise it's all stock components on a Rocket Cellini Evo V2, I change the group head gasket regularly when it starts to harden. I tamp with a 58mm conical and keep the rim clear of grounds by a quick wipe after tamping.

Just noticed the portafilter always has some play before locking in (greater diameter than shower screen apparently).

I'm wondering what makes grounds climb up to the seal in the first place and/or whether this is normal? Am I loading too much (happens on stock single and double baskets)?

Would be great if you could share your experience, no matter what make and model you're pulling shots from!


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## Mrboots2u (May 10, 2013)

What dose are you using , in what basket?


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## Hasi (Dec 27, 2017)

depends on beans, but I stick to keeping the upper edge of the tamping base (that one: https://www.bellabarista.co.uk/concept-art-tamper-base-convex-58mm.html) flush with the basket rims at max. Too little room? If that doesn't work with taste and I need to dose up, I switch baskets. It still keeps happening at all times, maybe got worse over time. But if I don't clean the group head gasket every time it wears super quickly and gets leaky...

PS: baskets are standard sizes that came with the machine, must be 7-10g, 18-20g. And there's a triple that looks just like the others I guess it's a 24g (?).


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## Mrboots2u (May 10, 2013)

Hasi said:


> depends on beans, but I stick to keeping the upper edge of the tamping base (that one: https://www.bellabarista.co.uk/concept-art-tamper-base-convex-58mm.html) flush with the basket rims. Too little room? If that doesn't work with taste and I need to dose up, I switch baskets. It still keeps happening at all times, maybe got worse over time. But if I don't clean the group head gasket every time it wears super quickly and gets leaky...


What weight of dose in what basket. Is the basket the one that came with the rocket?

I would weigh the dose as I suspect you may be overdosing .

Coffee needs room to expand.

I would guess you are over dosing to whatever basket you are using , weighing to 0.1g will tell us though .


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## Hasi (Dec 27, 2017)

yup, all stock - just edited the above.

My scale won't even tell me decimals as I haven't been into the weighing frenzy







yet... dialled in by feeling and taste only. Will try again with the double and triple in a direct comparison first thing tomorrow morning


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## Rhys (Dec 21, 2014)

I always weigh my doses so they match my basket (18g), although some beans produce more volume per mass so my coffee puck ends up glued to the shower-screen. Gets quite annoying as I can never remember which beans do it..

saying that, there's always some coffee stuck round the edge of the shower screen even when I'm very tidy with my portafilter. I have kitchen towel to hand and fold a piece to run round the group-head after giving it a flush.


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## les24preludes (Dec 30, 2017)

I have a Gaggia Classic and I'm thinking of getting an IMS shower screen - hopefully less grounds get stuck in it. The stock screen gets easily gunked up and it isn't so easy to clear all the holes. In fact, what's the best cleaning solution and procedure for clearing all those tiny holes?


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## ajohn (Sep 23, 2017)

It sounds like you have a fill level problem to me. Do your pucks knock out pretty cleanly ? If not it's probably too low depending on the amount left in. If dead cleanly it may be too high but that's likely to reduce the strength of what comes out. That effect can be pretty noticeable on a single basket. This can also force grounds into the shower screen as the coffee expands. If the pucks stick to the shower screen a bit more is needed - not much more either maybe 0.2g. If the level is just a little low and usable to the top of the puck might be a bit wrinkled rather than being flat. Go a much lower than that and there are likely to be clear signs of channeling. If things have to be like that the machine will need back flushing with a cleaner more often and the shower screen and spreader plate removed for cleaning more often as well. A change basket size is a better option. If a suitable size isn't available put up with it or change beans to some that work out better in this respect.

I find that a few grounds are nearly always washed out when I flush with an empty basket before pulling a shot. I use a BE though which has a simplified shower screen arrangement and fill problems mess it up pretty quickly. My Piccino is ok with a bigger range of fill levels but it's still not much. That uses a shower screen that is rather like the IMS types so filters what gets sucked back into the machine when the 3 way opens. There should only be rather fine grinds finishing up in the drip tray anyway.

It doesn't take that long to find out what a suitable weight for a basket is for a starter but bean types will vary it. Grinder setting will as well. I'm generally finding that once found the grinder setting usually doesn't need much of a change. Even with changes of basket size but down to the machine I am using I am nearly always running a brew pressure a touch short of where the OPV opens.

John

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## Mrboots2u (May 10, 2013)

Hasi said:


> yup, all stock - just edited the above.
> 
> My scale won't even tell me decimals as I haven't been into the weighing frenzy
> 
> ...


Try weighing. The time spent doing it will negate the guess work you are currently using.

You still taste the coffee by the way, even if you use scales.


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## ashcroc (Oct 28, 2016)

les24preludes said:


> I have a Gaggia Classic and I'm thinking of getting an IMS shower screen - hopefully less grounds get stuck in it. The stock screen gets easily gunked up and it isn't so easy to clear all the holes. In fact, what's the best cleaning solution and procedure for clearing all those tiny holes?


The IMS 200 µm is machined from a single plate if metal so is easier to clean. Even soaking in puly & scrubbing it's almost inpossible to clean everything out from the sandwich of the stock one (not that I could do that with mine as the screw was stuck).

Can't tell you how much of an improvement it is as I fitted a brass dispersion plate at the same time.


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## J_Fo (Dec 24, 2017)

ashcroc said:


> The IMS 200 µm is machined from a single plate if metal so is easier to clean. Even soaking in puly & scrubbing it's almost inpossible to clean everything out from the sandwich of the stock one (not that I could do that with mine as the screw was stuck).
> 
> Can't tell you how much of an improvement it is as I fitted a brass dispersion plate at the same time.


I've been looking at the brass dispersion plates and IMS screens this morning...

Since fitting a PID I've become much more aware of how much temp I'm losing over the duration of a shot, will the brass plate help with that?


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## ashcroc (Oct 28, 2016)

Jon_Foster said:


> I've been looking at the brass dispersion plates and IMS screens this morning...
> 
> Since fitting a PID I've become much more aware of how much temp I'm losing over the duration of a shot, will the brass plate help with that?


It has better heat retention than the stock ally one but I don't think that would show on a PID as it reads the temp at the boiler.


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## J_Fo (Dec 24, 2017)

ashcroc said:


> It has better heat retention than the stock ally one but I don't think that would show on a PID as it reads the temp at the boiler.


Oh no of course, bad phrasing by me, I just meant that since using a PID and becoming more aware about the temperature of the water/boiler, I've better understood the importance of keeping the temp around the group head as high as possible.

Think I might have to get one...


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## ajohn (Sep 23, 2017)

Hasi said:


> depends on beans, but I stick to keeping the upper edge of the tamping base (that one: https://www.bellabarista.co.uk/concept-art-tamper-base-convex-58mm.html) flush with the basket rims at max. Too little room? If that doesn't work with taste and I need to dose up, I switch baskets. It still keeps happening at all times, maybe got worse over time. But if I don't clean the group head gasket every time it wears super quickly and gets leaky...
> 
> PS: baskets are standard sizes that came with the machine, must be 7-10g, 18-20g. And there's a triple that looks just like the others I guess it's a 24g (?).


The usual E61 size baskets are 7, 14 and 21g. Going on ones I have used the 7 wont hold 10 and the 14 wont hold 18. You can also probably fine 6 and 12g baskets that will fit.

I suspect you'll find that 7 in the 7 and 14 in the 14 is a bit low but maybe not. You can tell from the puck as I mentioned. There can be another problem as well - the tamper wont reach down into the grounds. Something like maybe 8.5g or less should fix that on the 7. Unlikely to be a problem on a 14 or a 12 if you ever buy one. It most definitely is on a 6 I have. It needs 7 and a bit. The 7 tops out at about 8.5g, 9 is too much. Another version of it can just cope with 9.

The portafilter is never a precise fit on the shower screen there should be clearance. All that should get on the seal is coffee stains, pretty quickly if you are using really gunky beans. That will make the seal appear to go hard and cause leaks if it's not scrubbed off now and again with a grouphead cleaning brush - that should have an angled end so that you can damp it with hot water from the group head. Also use it to scrub over the shower screen.

I've had 2 machines where the owner didn't seem to own a shower screen. One was so bad that a new seal was needed. It needed a lot of force to get that one to seal. The other improved after using it but had probably gone too far - that one was "my DB" that went back for other reasons today. I caught my own BE in time so still have the 2 spare seals I ordered. What seems to happen is that oil and what ever builds up on the seal and hardens so it takes more effort to get a seal. If really bad a lot of effort. The Sage seals are silicone - seems to me having fitted one to a machine that usually uses rubber they aren't a bad idea but watch that you don't over tighten when they have settled down. Coffee residue will make even those behave like brick though.

One thing for sure until you have some idea what the baskets should hold and work as they should you may as well stand on your head and wave your legs around.







Then if you depart from that you'll know you have.

John

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## ashcroc (Oct 28, 2016)

ajohn said:


> The usual E61 size baskets are 7, 14 and 21g. Going on ones I have used the 7 wont hold 10 and the 14 wont hold 18. You can also probably fine 6 and 12g baskets that will fit.
> 
> I suspect you'll find that 7 in the 7 and 14 in the 14 is a bit low but maybe not. You can tell from the puck as I mentioned. There can be another problem as well - the tamper wont reach down into the grounds. Something like maybe 8.5g or less should fix that on the 7. Unlikely to be a problem on a 14 or a 12 if you ever buy one. It most definitely is on a 6 I have. It needs 7 and a bit. The 7 tops out at about 8.5g, 9 is too much. Another version of it can just cope with 9.
> 
> ...


Not had a problem with 7g in my 7g basket. The 4mm tamper I use with it may explain that but a 58 would never tamp it correctly no matter how much I dosed.


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## Hasi (Dec 27, 2017)

Pucks usually are firm and come out nicely. They don't stick or anything. Just residue up there.

Okes, going to buy a decent scale... my recent trials haven't shed too much light on the subject. Although I lean towards overdosing to be a possible reason. At least that would be easy to fix.

The other thing worth looking into would be some more baskets. Ridgeless?!


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## Missy (Mar 9, 2016)

Is it not something obvious like when the solenoid sucks the puck up after the shot is finished?


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## Mrboots2u (May 10, 2013)

Hasi said:


> Pucks usually are firm and come out nicely. They don't stick or anything. Just residue up there.
> 
> Okes, going to buy a decent scale... my recent trials haven't shed too much light on the subject. Although I lean towards overdosing to be a possible reason. At least that would be easy to fix.
> 
> The other thing worth looking into would be some more baskets. Ridgeless?!


Ridgless are easier to get out , thats the difference between ridged and ridgeless...


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## Hasi (Dec 27, 2017)

Makes sense - no retaining ring... I thought more in a direction of: diameter widens where tamper base should sit rather tight.


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## ashcroc (Oct 28, 2016)

Hasi said:


> Makes sense - no retaining ring... I thought more in a direction of: diameter widens where tamper base should sit rather tight.


When I've used a ridged basket the tamped puck has always been below the ridge. I did find I have to tap the grinds out of the ridge after tamping & retamp though. Going ridgeless has removed that step.


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## rob177palmer (Feb 14, 2017)

Jon_Foster said:


> Oh no of course, bad phrasing by me, I just meant that since using a PID and becoming more aware about the temperature of the water/boiler, I've better understood the importance of keeping the temp around the group head as high as possible.
> 
> Think I might have to get one...


You should.


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## rob177palmer (Feb 14, 2017)

I also understood that the the ridge was designed to disturb and slow the water flow down the sides, to try to reduce water being forced down the sides of the puck and channelling.


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## Hasi (Dec 27, 2017)

ashcroc said:


> When I've used a ridged basket the tamped puck has always been below the ridge. I did find I have to tap the grinds out of the ridge after tamping & retamp though. Going ridgeless has removed that step.


my thoughts exactly... retamping alters overall compression, and should be avoided. Caught myself dozen times doing like you described









Ridgeless baskets added to shopping list, right underneath the scale(s).


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## Hasi (Dec 27, 2017)

Freshly dialed in the grinder to see how much dosage can be reduced.

no less than 10g in the single basket, below won't work for the beans I currently drink (homemade Nicaragua medium roast, no oil







) checked extraction with my bottomless pf - all good and even nicer taste. Problem faded but is still there, maybe in every other shot.

Was looking into getting a set of decent baskets, as they appear to have plenty different sizes.

Someone with respective experience out there?


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