As I said before, when I switched from the stock Rancilio double basket to the synesso double (bought from Great Infusions) there was a huge difference on my Silvia. I definitely recommend that, but taking apart and cleaning the Rocky and changing the burrs is still the first step.

fwiw, i have a recently purchased silvia v3 and a recently puchased rocky doserless (both new in may 2010). i have the zero point on the rocky at zero on the dial, and it will choke the silvia if i grind a medium to lighter roast at 8 and a darker roast at 7.

i am using the stock silvia double basket (which i have also heard called a "14 g basket") in the stock portafilter. i have not been weighing my doses, just dosing by volume. i have not been doing any distribution. i level to just below the top of the basket with my finger and then tamp medium hard (58 mm tamper) which takes the level of the puck a couple mm below the springclip line in the basket.

the nut in the dispersion screen always leaves a divot in the puck after the extraction, but i haven't pulled the PF out dry to check if it is doing it before the pull. great idea ben, btw, to replace the stock screw with a flatter one. hardware store tomorrow.

shots are pouring in 25 - 30 seconds, so the mechanics are in the ballpark.

taste is taste and i am a long ways away from having a developed coffee palate, but the shots i am getting from the silvia and rocky are, to me, in range (sometimes better, sometimes worse) with what i can get at good cafe's around town. i still have plenty to learn.

based on my limited experience, if you can't grind fine enough to choke the silvia with the rocky, then i would bet that there is something wrong with the rocky.

napierzaza wrote:I'm using 49th Parallel - Epic Espresso so I don't know when it was roasted actually. But I did buy it from a pretty high volume cafe. Hard to tell.

BTW, 49th prints the roast date on a label on the bottom of the bag. Personally, i find that the Epic Espresso blend is harder to get right than other more forgiving blends (Intelligentsia's black cat or Ritual's sweet tooth). Especially if it's getting a bit old.

My two cents.

I noticed the comment about the dispersion screen marking the puck. I think this is inevitable on some machines. I've dosed as low as 13g on my Angeli and will still get a slight mark from the nut on the puck prior to pulling the shot.

I don't think this causes a real problem though. However, if i dose closer to 18-19g, then the mark is more pronounced and i even get cracks forming on the surface. Those shots usually do not end that well, i think the puck becomes compromised at that point.

I would suspect that other designs that do not have a nut (E61 comes to mind) might do better with updosing.

You might want to read the three posts on the topic I started a little while ago on Silvia pre-infusion. I have a Rocky grinder and I've never had problems with it and solving my channeling problem had nothing to do with the Rocky. I suppose that with a perfect grind and a perfect tamping technique channeling can be minimized on the Silvia, but what solved the problem for me was pre-infusion.
I think much of the criticism of the Rocky is unjustified and the common complaints like the steps rather than continuous adjustment and the amount of ground coffee that stays in the machine are easily handled.
I think the problem is primarily that full pressure quickly hits the dry coffee. There is no pre-infusion and the factory-set pressure is about 11 so it is necessary to reduce the pressure by adjusting the nut on the over-pressure valve and then either open the steam rod a little at the beginning of the shot or turn the brew switch on for two seconds then off for 3 seconds (you have to experiement) to pre-infuse the shot before the extraction continues.
That works for me and for Jesus who commented there

Let me add that I have success with doses from 7 g to 22 g and there is always a screw impression on the spent puck but that has never caused any problem with extraction speed or channeling at least not since I started the pre-infusion technique.