# At a loss what to try next! Extreme 'gushing' shots?!



## hullcoffee (Jul 27, 2021)

Hi all,

Newbie here!

I've a Silvia (2 years old) and have recently started experiencing 'gushing' shots. We've been using the machine absolutely fine daily and this was a sudden occurance.

I've changed the screen and gasket, used fresh coffee beans from our grinder and been through a process of grinding so fine as to choke the machine and then move the grind slightly, try again etc. As soon as I get to a grind not quite fine enough to choke but still very fine, water rushes through.

I'm struggling to believe that after 2 years my tamping technique has suddenly started creating extreme channelling!?

Is there something else I need to check? I'm this close to just throwing the thing in a skip!

Would appreciate any advice...

Thank you in advance!


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## lake_m (Feb 4, 2017)

Hi,

What beans and grinder are you using?

I experienced this with light roasts and decaf in combination with a Sage Smart Grinder. The grinder produces a lot of fines which create the 'nothing then everything' scenario (extreme channelling).

Try backing the grind right off, and then starting from coarse, go finer (but not too far, as the grinder is the limitation)

If you have a better grinder then check you are not over-dosing the basket (the 5p test), if so reduce slightly to improve channelling.


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## 29244 (Feb 8, 2021)

How many days post roast are the beans?


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## hullcoffee (Jul 27, 2021)

lake_m said:


> Hi,
> 
> What beans and grinder are you using?
> 
> ...





tompoland said:


> How many days post roast are the beans?


 Thank you both for replying. I appreciate it!
Beans are Union Roast Revelation, nothing too out there (my wife really likes them!).

Grinder - Mignon Silenzio

I've gone super-fine and choked the machine. Just for my understanding are you saying grind coarsely and pull a shot or just re-set the grinder? Sorry if that's a newbie question...

The big thing here is that *something* has changed as it was working great for our needs a week ago!


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## lake_m (Feb 4, 2017)

The grinder is fine.

No, I was suggesting you go coarse initially and then work your way finer.

Have you ever cleaned the grinder? i.e. removed the hopper, top burr and given it a good sweep out? Wouldn't do any harm.


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## hullcoffee (Jul 27, 2021)

lake_m said:


> The grinder is fine.
> 
> No, I was suggesting you go coarse initially and then work your way finer.
> 
> Have you ever cleaned the grinder? i.e. removed the hopper, top burr and given it a good sweep out? Wouldn't do any harm.


 Removed the hopper and 'cleaned' what I could see but haven't removed burrs at all. I'll get that done to rule it out.

In terms of going coarse first - would you use it in a shot as such or is it to reset the grinder itself? (Again, apologies if that's a daft question).

I've been playing around all morning and the results are identical each time at the moment. Water on, delay for a few seconds, bursts through in a mini-tidal wave of brown-ish water pretending to be coffee...


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## shadow745 (Apr 29, 2012)

For something like that happening quite suddenly with no real changes I'd check the OPV as if it's not functioning in a decent manner it will force all pump pressure right to the group and act exactly as you describe. When you extract or use a blind basket check flow from the OPV to the reservoir, as in the shorter hose. You should have some measurable flow.


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## The Systemic Kid (Nov 23, 2012)

Check the puck after an extraction. Leave it in the portafilter to cool right down and should then drop out after giving the portafilter a sharp tap on something like a chopping board. Are their signs of channelling - cracks or small pinholes in the puck's surface. If you have a bottomless portafilter, does extraction occur evenly?

Notice you say above, you have changed the gasket - did the problem arise after or before you replaced it?

Might be an idea to video and upload so we can see the problem at first hand.


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## yardbent (Aug 8, 2015)

shadow745 said:


> For something like that happening quite suddenly with no real changes I'd check the OPV as if it's not functioning in a decent manner it will force all pump pressure right to the group and act exactly as you describe. ...............snip


 does it look like this..? then the OPV is suspect as noted above


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## hullcoffee (Jul 27, 2021)

The Systemic Kid said:


> Check the puck after an extraction. Leave it in the portafilter to cool right down and should then drop out after giving the portafilter a sharp tap on something like a chopping board. Are their signs of channelling - cracks or small pinholes in the puck's surface. If you have a bottomless portafilter, does extraction occur evenly?
> 
> Notice you say above, you have changed the gasket - did the problem arise after or before you replaced it?
> 
> Might be an idea to video and upload so we can see the problem at first hand.


 I'll do just that 

Don't currently have a bottomless portafilter sadly. Gasket changed as a response to this starting to happen...



shadow745 said:


> For something like that happening quite suddenly with no real changes I'd check the OPV as if it's not functioning in a decent manner it will force all pump pressure right to the group and act exactly as you describe. When you extract or use a blind basket check flow from the OPV to the reservoir, as in the shorter hose. You should have some measurable flow.


 OPV? (Sorry, total newbie!)

Being honest, it does *feel* like something mechanical has changed suddenly.

Thanks all so far!


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## hullcoffee (Jul 27, 2021)

Just showing the water through the screen - it seems to end up as two strong streams as opposed as 'shower' - or is that a red herring?!


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## El carajillo (Mar 16, 2013)

> 18 minutes ago, hullcoffee said:


 Red herring, without the P/F and a basket filled with coffee that is perfectly normal


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## hullcoffee (Jul 27, 2021)

El carajillo said:


> Red herring, without the P/F and a basket filled with coffee that is perfectly normal


 Thank you


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## shadow745 (Apr 29, 2012)

hullcoffee said:


> I'll do just that
> 
> Don't currently have a bottomless portafilter sadly. Gasket changed as a response to this starting to happen...
> 
> ...


 Over Pressure Valve, which is what diverts excess pressure back to the reservoir instead of full force at the group. The OPV is quite simple and relies on a spring/plunger to control flow. It can clog with sediment/scale and not function properly consistently. Next extraction you do open the lid to the water reservoir and hold the shorter hose up out of the water. If you grind fine enough to cause an over pressure situation you should see that excess flow being sent back through that hose. You can also check that by running the pump a bit with the blind basket in place, which should give you quite a bit of back flow. Sometimes the OPV needs to be taken apart for cleaning or even rebuilt/reset, which is cheap and easy.


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## hullcoffee (Jul 27, 2021)

You guys have been great so far! Thank you!

Here's what's happening as requested earlier in the post.

I am 100% certain that my technique isn't what it could be but the thing that's blowing my brains out is that we were all good and then suddenly we weren't.

Pre, video of extraction and post-puck on the link. Feel free to be brutal about the technique (I want to learn!) but the oddity is that we could get a decent-to-us shot and now this is happening...

https://share.getcloudapp.com/JruDKYgG

https://share.getcloudapp.com/L1uB0lgX

https://share.getcloudapp.com/NQuoymKL


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## lake_m (Feb 4, 2017)

That grind looks too coarse. Some boulders in there!


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## Rob1 (Apr 9, 2015)

The grind is way too coarse.


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## yardbent (Aug 8, 2015)

^^^ agreed - too coarse

and (newbie observations - so experts can refute.. :classic_smile: )

(A).....*.img-8340* whats the *rim* in the coffee around the edge of the basket..?

what is the inside diameter of the basket.?

what is the outside diameter of your tamper.?

cos the *rim* is a puzzle;..if grounds NOT tampered fully/evenly it can lead to channeling

(B) img-8343

once again the edge 'rim' is evident

what is the great hole...? a super channel caused by excessive pressure from OPV..?......... :classic_ohmy:


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## Rob1 (Apr 9, 2015)

The hole is from the screw in the shower screen. Presumably from the puck expanding when the shot has ended. I assumed the dose would have been checked when locking the portafilter to ensure it wasn't disturbed at that point.


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## Stevebee (Jul 21, 2015)

Echo everyone else - way too coarse. Re dose, a. Grind finer b. Put a 5p on top of tamped portafilter and lock in. C. Look for the 5p to make a slight impression only, not pressed in all the way - correct dosing. Make sure you grind finer first though.


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## hullcoffee (Jul 27, 2021)

Much finer and it chokes the Silvia but will try!

Appreciate the help folks. Stand by for an update tomorrow 

And I'm baffled as to why the change has occured between drinks. In the morning, fine. Later the same day, this level of disaster...


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## shaun**** (Oct 24, 2015)

hullcoffee said:


> Much finer and it chokes the Silvia but will try!
> 
> Appreciate the help folks. Stand by for an update tomorrow
> 
> And I'm baffled as to why the change has occured between drinks. In the morning, fine. Later the same day, this level of disaster...


 Does the water seem hotter than it used to be? This was one of the symptoms when the boiler thermostat on my gaggia classic started to play up. When it was significantly over temperature the shots would gush like nobody's business.


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## hullcoffee (Jul 27, 2021)

shaun**** said:


> Does the water seem hotter than it used to be? This was one of the symptoms when the boiler thermostat on my gaggia classic started to play up. When it was significantly over temperature the shots would gush like nobody's business.


 I've not noticed but will check to see what temp is.

I'm clearly a coffee idiot (keen to learn!) but this does feel like something 'snapped'. I don't understand why it would be so different.

Will try again in the morning!


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## shadow745 (Apr 29, 2012)

hullcoffee said:


> Much finer and it chokes the Silvia but will try!
> 
> Appreciate the help folks. Stand by for an update tomorrow
> 
> And I'm baffled as to why the change has occured between drinks. In the morning, fine. Later the same day, this level of disaster...


 Yes now that pics are presented the grind could be a touch finer and go from there. I despise the lame stock hex head screw that causes that. Some think it makes no real difference, but after having done over 10,000 extractions on the V1 Silvia I had I know better. Switching to the flush mount design instantly cleaned things up.

For some that may think the OPV has nothing to do with things that get out of hand clearly has never dealt with one malfunctioning, which I clearly have. Also had that to fluctuate as in be fine for days to weeks, then stick shut and force all pressure to the group.

For your morning/evening changes... ambient temp/humidity can seriously affect grind fineness needed. Also, if you haven't purged any remaining coffee from the grinder anything sitting for an period of time will loose that freshness and cause fast extractions.


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## Rob1 (Apr 9, 2015)

Small adjustments go a long way on the mignon. If a slightly finer grind chokes the silvia you've got problems with the machine, you might need to replace the pump if it can't get up to pressure.

If you've started getting gushing shots and weren't before it's a process of elimination.

If you're using the same coffee and the grind setting is the same and the machine suddenly gushes then.....is the coffee getting stale, is it left in the hopper in the sun, have you started single dosing, etc?

Eliminating those possible causes you look at the machine.

Is the pump coming up to pressure, if the flow rate normal, are there any blockages, is the opv working? If the opv has broken somehow and the machine has gone from delivering 9 bar to the puck to 15 bar then you'll see the machine choking at the same grind setting you were using before, but the shot might eventually speed up and gush out (so with a spouted pf you'd see a longer time before first drips followed by a weird erratic flow if it starts to channel). Checking the opv and return to the tank seems the best thing to do.


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## hullcoffee (Jul 27, 2021)

Thanks all - will give it a go tomorrow! Wish one of you lived near Hull!


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## 29244 (Feb 8, 2021)

What would be really great is if one of ours steamed experienced members could create a troubleshooting checklist for this problem. Please? Not looking at anyone in particular @DavecUK😀


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## shadow745 (Apr 29, 2012)

tompoland said:


> What would be really great is if one of ours steamed experienced members could create a troubleshooting checklist for this problem. Please? Not looking at anyone in particular @DavecUK😀


 Seriously, lmao? Pretty much everything to address has been listed and some of us have quite a bit more experience/knowledge than you might admit/imagine. Too many fanboyz in forums/subs these days, time for me to roll!


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## 29244 (Feb 8, 2021)

shadow745 said:


> Seriously, lmao? Pretty much everything to address has been listed and some of us have quite a bit more experience/knowledge than you might admit/imagine. Too many fanboyz in forums/subs these days, time for me to roll!


 No offence meant nor slight intended to your experience or capability. Fanboyz, maybe. Dave is one of the few I know here but it's true I value his advice.


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## hullcoffee (Jul 27, 2021)

Good morning folks - firstly, can I say how helpful I've found all of this? You've been amazing so far.

Managed to get something looking like a shot out of the machine after plenty of attempts! I'm sure it's not properly dialled in just yet but...

https://share.getcloudapp.com/QwuAPkjk

Although the screwhead thing is irritating me now I've learned a little more -> https://share.getcloudapp.com/7Kuo78jW
Did someone say there is a mod for that?

I'll keep tweaking but seems like I might be able to crack it thanks to your help...

(Still blows my mind that it just *stopped working* and needed all of this but hey-ho!)


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## The Systemic Kid (Nov 23, 2012)

Good to see you're getting there.The shower screen screw indent into your coffee bed suggests you are dosing too much for the basket you're using. For even extraction, there needs to be enough room between the shower screen and the top of the puck to allow for expansion during initial stage of extraction. If the puck doesn't' have enough room to swell, the result can be channeling.

What is the recommended max dose for for the basket you are using? Try reducing the dose until the impression is either feint or disappeared. You will have to adjust your grind accordingly, i.e. go finer.


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## hullcoffee (Jul 27, 2021)

Thanks - will keep trying!

Is it worth getting a bigger basket? (This is the stock double basket, 14g in it)


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## The Systemic Kid (Nov 23, 2012)

As I recall from my Silvia days, stock is 14 grm.



hullcoffee said:


> Thanks - will keep trying!
> 
> Is it worth getting a bigger basket? (This is the stock double basket, 14g in it)


 Depends on the coffee you're using, i.e. roast level. With darker roasts, you don't need to dose as much as is the case with lighter. Might be worth picking up an 18grm basket which would give you more options to create bigger gap between puck surface and shower screen to allow for expansion.

If you are dosing 14 grm into your stock basket, try reducing dose by a couple of grams and see if this eliminates the shower screen nut indent. Adjust the grind finer and aim to keep extraction in the 25-30 sec range. Ideally, weigh your shot output and aim for a 1:1.5 - 1:2 ratio - e.g. for 14 grm dose shot output should be 21-28 grms.


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## lake_m (Feb 4, 2017)

14g is the traditional Italian double shot basket, but many manufacturers are now supplying larger baskets with their machines - If you're looking at bigger baskets you just need to be careful that it's not too deep that it won't go into your spouted portafilter. 18g should be OK, and the Silvia can use standard readily available (E61 etc.) 58mm baskets. IMS are pretty good and aren't too expensive.


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## hullcoffee (Jul 27, 2021)

Thanks both!


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## shadow745 (Apr 29, 2012)

hullcoffee said:


> Thanks - will keep trying!
> 
> Is it worth getting a bigger basket? (This is the stock double basket, 14g in it)


 The stock baskets are a joke for my use... even the stock basket that came with my Silvia Pro sits unused. Have been using the 40-100-103 basket for quite a few years and it's been superb. Used it with my V1 Silvia and of course now the Pro. Have read it's been 'updated' even more and the latest version isn't as good as what I've been using. This is where I sourced mine and the basket quality and performance in the cup is simply unbeatable.

https://www.espressocare.com/products/item/rancilio-double-basket-redesigned-2014-18-grams

This guy sells the flat screen kit and it's a big improvement in performance as there is no puck fracturing from updosing and it is easier to clean than the stock setup. Actually bought from him recently to replace the stock screen setup on the Pro machine. Rancilio has made a bit of improvement with the current screen as it's somewhat flush mount, but still not very tight tolerance that you'd expect to go along with such a superb machine. Also, the stock screen with the machine brand new was slightly tweaked as in not perfectly flat.

http://store.pidsilvia.com/index.php?route=product/product&product_id=56&search=flat+screen

Granted you can stick with the stock setup, decent dose, etc., but I won't waste time/effort being stuck in the 14-16 gram dose range just to pacify the machine in stock form. With that basket/flat screen my average dose is 19 grams or so and superb extractions. Extreme flavor profiles and very heavy texture, which is exactly what I seek out. Never was able to get close to that with the machine using those stock parts.


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## hullcoffee (Jul 27, 2021)

shadow745 said:


> The stock baskets are a joke for my use... even the stock basket that came with my Silvia Pro sits unused. Have been using the 40-100-103 basket for quite a few years and it's been superb. Used it with my V1 Silvia and of course now the Pro. Have read it's been 'updated' even more and the latest version isn't as good as what I've been using. This is where I sourced mine and the basket quality and performance in the cup is simply unbeatable.
> 
> https://www.espressocare.com/products/item/rancilio-double-basket-redesigned-2014-18-grams
> 
> ...


 Thank you!


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