# VST / Gaggia Classic - what am I doing wrong?



## delgag64 (Feb 20, 2016)

I recently switched to an 18g VST basket in my Gaggia Classic. While I have a naked portafilter handle, I'd rather use a spouted one. When using the VST in the original Gaggia handle I find it a very snug fit into the group head, as other forum users have reported. The advice elsewhere has been to look at buying a slightly thinner gasket, which I will do.

But I fear I have encountered a bigger problem, beyond mere difficulty screwing the thing in. I have found that anything even remotely close to an 18g dose means the grinds are coming right up against the screen when wet. I consistently get shots which start off pouring far too slow, then as the coffee expands, I get rapid channelling along the four corners (where the holes in the group head are).

I am am down to dosing just 16g and I still seem to have this problem. I'm wondering: can a .5 mm difference in gasket thickness really solve this? Am I doing something more fundamentally wrong?

all advice welcome, including suggestions on whether IMS might be a better fit.


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## Mrboots2u (May 10, 2013)

Coffe expands when wet , this is fine.

Dose can be 17-19g , if you are using darker roasted coffee with a coarser grind you may need to drop the dose a little.

How is the headroom before you make coffee. Stick a 5p coin on top of the coffee lock in. Does it lock , does it depress in the coffee?


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## El carajillo (Mar 16, 2013)

Do you have a grinder ? Make ? or are you using pre-ground coffee ? Is the coffee fresh / rested ? Are you evenly distributing the grounds WDT ?

If you fit a thinner gasket / seal, this will compound the problem by moving the basket up closer to the brew head =even less headroom =less coffee.

At what angle does the PF lock in ? 5 / 6 /7 oclock ?


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## delgag64 (Feb 20, 2016)

Thanks for the replies.

With effort, I can get it to lock in at 6 o'clock.

I am using freshly ground, mostly from a Sage grinder. Using a dark roast but have also tried medium and much the same result. Coffee is about 10 days old at this point but I haven't noticed any discernible change since I first got it.

I hadn't even done the 5p test since the group head screw is already indented very clearly on the puck.

El carajillo - yes I completely take your point. By solving the gasket issue I'll compound this.

With a naked pf it works better - I still don't get much headroom but I don't have the same issue of choking then channelling.

Could it be something the matter with my OEM Gaggia pf handle? I did get it second hand...

Even with the standard basket I've noticed recently that the gasket seal doesn't seem to be that good; a little drop always escapes round the seal before the pour starts. It's been about 14 months so I suppose due a change anyway.


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## Mrboots2u (May 10, 2013)

Try the coin test report back

Out of interest what's the coffee


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## El carajillo (Mar 16, 2013)

Definitely change the seal, try a silicone one= softer& more squidgy (technical term).

If it is locking in differently with the spouted P/F and leaking around the edge, it could be the VST is too deep for the P/F and is resting on the bottom of the P/F. Check depth of P/F with a rule and check the depth of basket into the rolled lip at the top, also check the radius on the bottom of the basket compared to the radius in the bottom of the PF. The basket can sometimes sit on the bottom curve of the P/F


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## Agentb (Feb 11, 2017)

Very odd... I have the same a VST 18g and Gaggia classic.

I use a convex shaped tamper which i guess gives me a 1mm i guess towards the centre. I don't put much pressure on the tamping side but 18g looks like this.










and










I have two PFs, one original Gaggia and a naked PF. I have a couple of different baskets including original Gaggia, and swapping them around they all lock in at at roughly the same position say 6oclock.

You don't say what happens if you swap PFs around - does the problem remain?



> the gasket seal doesn't seem to be that good


 No harm in getting a replacement - just be sure to get the correct size as there are several different widths - and there is an up and down side. I would get the gaggia genuine gasket or better the silicone one. (I don't have the silicone one but a cheap Gaggia clone one i did buy is not going to last long and it feels like it's made of wood!)

Have you checked your scales - may sound obvious? A pound coin weighs 8.75g so two is 17.5g.

is it possible the shower screen is not seated corrected?

Hope that helps...


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## ashcroc (Oct 28, 2016)

I have 3 portafilters (1 cast gaggia, 1 standars spouted & a worn generic naked) with a few different different baskets (no gaggia ones though). They all lock in at different points from 6 o'clock onwards depending on the combination.

The blue cafelat seal I fitted in late 2016 is still as supple as the day it went in. It's a bit squishier than the standard rubber one which helps.


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## ajohn (Sep 23, 2017)

IMHO Overfilling usually helps prevent channelling so wouldn't be surprised if more coffee is needed when the coin test is done. A tiny bit of over filling doesn't cause much of a problem as it hardly changes a grinder setting - it can be a bit of a knife edge past some point needing a significantly coarser grind = weaker coffee.

Beginners reading about light tamping may not be a good idea. I'd suggest straining a little to keep it fairly consistent and then play around with lighter tamping when things are working. One lady who light tamper on here uses 10kg, extremely precisely and at great cost, I use 15







sort of semi light and a much cheaper tamper. Both are light. This area can cause channelling. Severe clumping in the grounds can too.

I've fitted new silicone seals to 2 machines. Initially both were on the hard side - cured by initial excessive force and swinging the handle too far once. Both then softened a bit more with use. They don't take much effort on the handle to generate a seal. To be honest I can't see how problems here would cause channelling.

John

-


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## Mrboots2u (May 10, 2013)

I wouldn't recommend straining when tamping, it's not good for the wrist. just push til you can feel no resistance.

10lb either way in pressure isn't gonna make or break your shot . Getting it level and the coffee in the bakset is .


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## dev (Jul 28, 2017)

delgag64 said:


> I recently switched to an 18g VST basket in my Gaggia Classic. While I have a naked portafilter handle, I'd rather use a spouted one. When using the VST in the original Gaggia handle I find it a very snug fit into the group head, as other forum users have reported. The advice elsewhere has been to look at buying a slightly thinner gasket, which I will do.
> 
> But I fear I have encountered a bigger problem, beyond mere difficulty screwing the thing in. I have found that anything even remotely close to an 18g dose means the grinds are coming right up against the screen when wet. I consistently get shots which start off pouring far too slow, then as the coffee expands, I get rapid channelling along the four corners (where the holes in the group head are).
> 
> ...


Are you distributing the grinds, WDT or similar? VST baskets are a bit more finicky as they require a good grind and distribution.

I'd recommend the IMS Competition basket 12-16g made for Gaggia. It's a lot more forgiving.


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## Benlowen (Mar 3, 2019)

I know this doesn't help you much, but I only have the 18g VST which I use in my standard Classic portafilter on my 2015 machine RI9403/18. I always dose 18g and have never had a problem with locking it comfortably in the 6 o'clock position with normal force. Saying that, I usually see a slight imprint of the screw/filter holes and sometimes not if I use 17grams.

Im only saying this if it gives you something to compare to, keep us updated and good luck.

Just remembered that when I started using the VST, it was a bit tighter fitting at first but that very quickly changed and it bedded in nicely. The original Gaggia basket was actually a fraction lower sitting with a slightly lower profile on the curved rim and it actually went past the 6oclock position far too easily, the VST is actually a perfect size and fit.


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## Benlowen (Mar 3, 2019)

Your level of tamp looks normal and about the same depth as I get each time, just below the ridge, as it should be apparently. Are the ears thicker on the bottomless this not allowing you to turn it in as far?


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## winz (Oct 10, 2019)

Hey guys! Reviving this chat.

i recently got a VST basket too with original gasket on my Gaggia Classic 2019. I dose 18g. But I notice a depression rim. As in the photo below :









could the Rim be due to the circumference protruding from the side of the shower screen? 








does anyone get this issue too?


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## winz (Oct 10, 2019)

winz said:


> Hey guys! Reviving this chat.
> 
> i recently got a VST basket too with original gasket on my Gaggia Classic 2019. I dose 18g. But I notice a depression rim. As in the photo below :
> 
> ...


 One more thing, I seem to be getting the same symptoms as the original poster. It takes about 6-8 seconds to start flowing, then rushes through. But I managed to get 26s for 35g


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## El carajillo (Mar 16, 2013)

It is not that unusual for the coffee to touch the screen, as the coffee is wetted it expands. Depending on the level of the coffee in the basket when dry this can happen.

Providing there is room for the coffee to expand initially ( try the coin on a dry compressed puck ) no indentation + OK. The clearance can vary depending on bean type, fineness of grind and age of coffee. Try the WDT trick on the coffee before tamping , this breaks up any clumps and helps distribute the coffee.

The coffee will start to flow faster towards the end as the puck becomes soaked and the pump pressure ramps / builds up.


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