Constant coffee grinds in water. Dirty machine?

[bentkalec]

Hello all,

After picking up a V3 Silvia 2nd hand, a thorough descale and backflush was performed and I pulled the group head apart and cleaned. For the last couple of months, daily water back flushing, followed by weekly chem backflushes are performed. However, no matter what I do, water pumped through the group head is riddled with old coffee granules. Is another decent descale in order? I'm using a bench top filtration system from Bombora.

As a side note, I notice that my tamper isn't super tight, maybe 0.5-1.0 mm slack and there are always a few grounds that end up stuck in the basket ridge. After brewing there is also ALWAYS quite a lot of grinds stuck to the shower screen. I am using the Rancilio 'Precision' 18g basket most of the time. Will un-tamped grinds be more inclined to be sucked up by the 3-way solenoid and lodge in the brew path somewhere?

Your feedback would be most appreciated.

Kind regards,
Ben

[grimsby]

Hi Ben,

Do you remove the shower screen and backing plate and clean both items on a regular basis? Grounds build up around the edge of the backing plate above the showerscreen lip and cleaning with a bent brush is only partly successful.
Removing and cleaning these items each day should fix your 'grounds' problem.

Alan

[Kevo]

After brewing there is also ALWAYS quite a lot of grinds stuck to the shower screen. I am using the Rancilio 'Precision' 18g basket most of the time. Will un-tamped grinds be more inclined to be sucked up by the 3-way solenoid and lodge in the brew path somewhere?

Your feedback would be most appreciated.

Kind regards,
Ben

Hi Ben.

If you've ALWAYS got a lot of grounds on the shower screen, you are almost certainly overdosing the basket IMO.
Admittedly, I'm not familiar with your machine, but it stands to reason if a lot of coffee is left on the shower screen then there is not enough room for the water to enter and slightly expand the grounds for a good extraction.
You can try filling the basket to your normal level, lock it into the group head, then remove it. If the surface has been even slightly disturbed, then start down dosing.

Try a 12-6-3-9 o'clock tamp to overcome the possible undersize tamper.

You don't mention the pour rate/consistency. How is the 30ml/30sec ratio? Also, if it's a weak/thin pour, then that can be from overdosing.
Down dose the 18g basket to 16g (weigh it) and play with the grind size and tamp pressure and see if that lessens the issue.

[bentkalec]

Grimsby,
A good clean was performed today, and as suspected there was some dirtiness hiding up inside the group. It had been about 7 weeks since I last pulled it all apart, so I now know that is far too long between cleans. Thanks.

Kevo,
I have read a lot in my 4 months of making espresso, so I feel I am extremely well read in Silvia espresso theory. As such I am very consistent with ensuring good dosing and head space above the puck. I use between 16-18g of coffee depending on the coffee itself. There is no imprint from the hex bolt usually before brewing. Shots are pretty decent in terms of time/volume, somewhere between ristretto and espresso. I did try the nutating tamp for a while but found I had channelling through the centre of the puck. Maybe I was too forceful on the edges?

Cheers

[Dimal]

I did try the nutating tamp for a while but found I had channelling through the centre of the puck. Maybe I was too forceful on the edges?

G'day Ben...

The idea of the so-called Nutating Tamp method, is to push the coffee around the Filter basket using the Tamper but without applying any downward force while doing this. After a couple of revs, ensure the tamper is level and apply your usual tamping force. The Nutating action is meant more of a way of distributing the coffee evenly throughout the Basket before applying the Tamp proper...

Mal.

[bentkalec]

Sound advice, maybe I'll give it another go.

Cheers Mal!