rancilio silvia problem

[hughharden]

Lately my rancilio has been taking a long time to push coffee through the holder at first, then all of a sudden comes through in a rush along with some grounds. When i look at the puck it looks like it blew through in one spot near the outside.

Could the grind be too fine causing this or is it another problem?

 

[Alex_chef2000]

Hi there, check first your water intake, it should always be cold. If it is warm or hot, you may need to replace your checkvalve at once.

I had the same problem once, so I went to a Home Depot and bought a Checkvalve of a water heater and it solved my problem, quick and easy in about 10 minutes.



Regards from Mexico,



Alex.:

 

[mrgnomer]

Lately my rancilio has been taking a long time to push coffee through the holder at first, then all of a sudden comes through in a rush along with some grounds. When i look at the puck it looks like it blew through in one spot near the outside.

Could the grind be too fine causing this or is it another problem?

It could very well be that you're grinding fine enough to choke the Silvia and your dose, distribution and tamp doesn't allow for a good seal at the edges of the basket. This would explain no initial flow then fast flow. The fast flow is probably channelling since you see it in the puck after extraction. Is the shot very light and runny? Have you tasted it? Is it kind of flat and bitter? If so, it's probably channelling.

The Silvia's stock pump pressure is set pretty high, atleast in the older machines. I hear they're coming out with an adjustable OPV so you can play with the pump pressure but there's no changing the pump pressure on older machines without modifying the OPV. That means the Silvia will generate more than 9bar, maybe as high as 11bar during extraction. That pressure will blow through an unevenly distributed/tamped puck.

I would try grinding coarser and be careful with your dosing, distributing and tamping to ensure evenness and a good seal around the edges.