Post By spin_addict
Rancilio Siliva - suddenly getting blond gushers after cleaning
Background: I'm using an old Rancilio Silvia (circa ?2007) which has consistently made my dad and now me great coffee. I've paired it with a Sunbeam EM0440 grinder (not the best I know, but it's done the job thus far).
The lead up: For the last few weeks, I've been pulling great shots with this set up - 20-25s for 30mL, great crema, great taste. Having recently taken ownership of the machine after my dad replaced it with a new Silvia, I decided to give it a deep clean. This turned out to be desperately needed with probably months of gunk all through the group head. I soaked all the removable parts in coffee detergent, gave it all a good scrub, descaled the machine and backflushed it a bunch of times. I finished up by running a few litres of fresh water through the machine to thoroughly rinse it out.
The problem: Ever since cleaning the machine, my shots have pulled extremely quickly (less than 10s) with rapid blonding, no crema and a bitter taste. I'm using the exact same beans, grinder/settings etc as before when everything was going perfectly.
Troubleshooting so far: My immediate suspicion was that cleaning out the gunk had allowed greater pressure at the group head and was producing channeling which I had previously avoided. I tried reducing the grind to the finest possible, all the distribution techniques I could find. I decided to upgrade my basket/tamper to a VST 18g with a well-fitting 58.3mm tamper and I splurged for a naked portafilter to help figure it out. None of this helped: the naked portafilter showed the same thing I assumed: the shot starts too quickly but seems relatively tight, then after a few seconds switches to a blond gusher.
With the suspicion that increased pressure was the culprit, I tore open the machine and loosened the OPV as much as possible; this had no discernible impact.
At this point I'm at a complete loss. All the advice I've read suggests that beans/grinder are the problem, but the exact same beans/grinder were perfect only hours before.
I'd love any help/advice!!
Test your brew pressure with a gauge. Grind finer if your Sunbeam is up for it.
can you grind fine enough to actually choke the machine?
I used to be able to choke the machine but not since the clean. I just added a shim to the grinder which should calibrate it a bit finer.
I bought some fresh ground beans from a Cafe down the road as a test and it ran a little bit longer but was still around 12-13s. I'm going to try them again with a harder tamp because at some point I must be able to choke the machine right?
I’d check the overflow hose that flows back into the tank during the shot. its plausible that the OPV has an issue and you are pushing WAY more than 9 bar and the associated flow rate is much higher.
A pressure gauge on the machines would be very handy to fault find it.
I have noticed that there's never really water coming out the overflow hose. I have taken the OPV apart and everything looks in order there but it's entirely plausible that there's something wrong further inside.
I'm going to try again in the morning grinding as fine as I can get but otherwise a pressure gauge might be in order. I think at that point I'll just take it over to Di Bartoli for a proper look over from a professional. I just wish I had never cleaned it now!
I believe so - from the few machines and grinders I've had experience on I usually dial the grinder down until it chokes the machine and then back it off several clicks and use that as the starting point to dial in the shot.
Originally Posted by RancilioPiccolo
Go back to your last known good configuration. Vst baskets can be tricky so take that out of the equation.
Yep the change to VST basket is the change thats the cause.
Id be surprised if you can dial in a Emo440 to a VST basket.
Try a number of Shims if you havent already And do the other mods such as ....
Well Ive forgot..its been that long.
Look do yourself and Mollie a favour and seek out a micrometric adjustable grinder then
you'll be able to match it to the VST.
You wont look back!