Extraction ratio WAY exceeding pump pressure

Need help with equipment usage or want to share your latest discovery?

#1: Post by EStirling »

So, have a Rancilio Silvia V3. It was used and abused, but I think in decent shape. I've cleaned the grouphead, replaced the shower screen, but seems to pump WAY too much fluid through.

When I use 12 - 14 grams of ground coffee, I end up with about 100 grams of liquid espresso or more within 20 seconds.

I've tried with my grinder (a fully cleaned and maintained Rancilio MD40), with Illy pre-ground espresso grounds (Ground Espresso Intenso Coffee - Dark Roast), and it's always the same. Set my grinder for the finest setting before the burrs grind on each other, same issue.

I've tried calibrating the pump pressure based upon the Ulka overflow pump tube flow, reducing the pump pressure based upon the median, maximum and minumum flow rate, all too much flow!

The puck looks super soupy on top afterwards.

Any suggestions? I could use the help of someone chasing the non-obvious solution!

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#2: Post by RapidCoffee »

Hi Earl, and welcome to H-B.
EStirling wrote:Any suggestions? I could use the help of someone chasing the non-obvious solution!
Sorry but I'm going for the two obvious culprits:
1. stale coffee - use freshly roasted beans, not preground
2. coarse grind - grind finer (much finer) and try updosing (how much depends on the filter basket)

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#3: Post by Jeff »

If you're using a typical "double" basket, 12-14 g of grinds may be complicating things as well. Roughly how much space is there from the top of the tamped puck to the top of the basket? 1/4", 1/2", more?