Hi All,
I've read quite a few posts here and there is a wealth of information available. Some background. I just recently upgraded to the Silvia/Rocky from a Breville800ESXL piece of junk. The only thing going for the Breville was that it had a HX instead of a boiler which was nice for those early morning shoot and go coffee's (wasn't espresso by any shot of the imagination, but OK coffee)

I do have a real quick question about grind fineness, dosing, and tamping. I'm using some locally roasted beans that are about 5-7 days old. I've pulled maybe 20-30 shots so far form my new Silvia/Rocky combo with very mixed results, and have "sink shot" about 50% of those.

I'm wondering if I'm not grinding fine enough? On the stock Silvia double basket, I grind about 9 up from "true" 0. (which happens to be 9 on my Rocky). WDT the grind. Level off with a knife, and tamp at around 30-50lbs force with a flat bottom RegBarber 58MM tamper. I haven't actually checked my tamp weight, but I'm sure it's pretty hard. If I go any finer on the grind with the same tamp I choke the machine.

My shots are in the 25-30 second range for ~2oz liquid, but they start VERY dark, and blonde very early (after about 5-10 seconds) I've tried numerous "Surfing" techniques on this machine, and the pulls all seem to be about the same. Very dark beginning, and blonde after about 5-10 seconds. The coffee is also pretty sour. There is good crema in the cup, but I think this is more a product of fresh beans, than proper technique.

Should I fine up the grind and tamp with less vigor? or are there other major issues here that I'm missing?

Any suggestions appreciated.

Get out the scale and "weigh" the tamp. A very hard tamp could be masking a too-coarse grind.

Go to my website and read the "How To" article #12 in the right-hand column. Well over 10 pages of typed information aimed at helping the home barista get better espresso and solve problems.

Also check the temp surfing instructions and the how to check brew temp article, again, all in the right-hand column.

I really don't know much about roasting techniques so i might show some ignorance here, but might learn something also.

Could roasting technique affect the quality of a shot? i am sure the answer here is a complicated yes, but my question is more attempting to figure out what is different between a "regular coffee" roast, and an espresso roast?

The coffee i first put through my silvia did not give me anything that resembled even the worst shots i am pulling currently. The coffee was fresh, and from a local roaster, but was just not the same quality as what i have been ordering from Intelligentsia, and Counter Culture.

Just a thought.

Randy may be more right with the temperature angle. I know i had a lot of problems dialing my machine in along with my grinder. I bought used which was half of my problem. I also took a digital thermometer apart, and screwed the wire to the top of the boiler. My own Ghetto PID.... Well not a PID, but a good way to read temp from the top of the boiler.

I am getting pretty good results with pulling shots around 212 to 215
-Donovan

I'm not sure, but 9 seems awfully high for the true zero (where the plates come in contact). Mine's at around 3, and I end up grinding at around 10 or 11. Just for the hell of it, have you tried grinding at around 10/11? The other variable that I've found to be critical with Silvia is water temperature. I've given up on following the light at all. Instead, if I'm making a cappa, I turn the machine on, let it heat for 15-20 minutes and run some hot water through the boiler. I switch off the hot water and press the steam button and let it heat for another 7-10 minutes or so, then steam my milk. I then grind my coffee, tap and tamp. but before attaching the portafilter, I turn on the brew button and pour a blank shot to bring the temperature down a little. Then I attach the portafilter for about a 27 second pour. I've had pretty consistent results doing this

Thanks all for the advice. I tried a couple things tonight just to see what would happen. I didn't end up drinking any of it, but did a lot of taste testing.

I ended up going through a quarter pound of coffee, but here's what I did..

I ramped the grinder down to 5, did a light 30lb tamp.
Machine choked

Moved grinder to 6, did the same 30lb tamp.
Machine choked

Moved the grinder to 7, same 30lb tamp.
Machine choked

Moved grinder to 8, same 30lb tamp.
pulled a very slow 1oz. very dark and bitter

moved grinder to 9, 30lb tamp.
Pulled 2.5oz in 20 seconds, early blonding

Modded grinder

Moved grinder to 8.5, 30lb tamp
Now we're getting somewhere. 25 second pull. Lots of dark crema.. still a little sour.

OK, so now I'm in to temperature issues, more than getting the grind and tamp right for flow rate. That's still going to take some practice, but making the rocky stepless, and going to 8.5 with a 30lb tamp seems to be doing the trick with this batch of beans.

On the beans, I had a shot at the local roaster and it was VERY good. they were using a La Marzocco/Mazzer setup and he pulled a beautiful naked shot in front of me. (sounds sinful, tasted better) I purchased a pound of the same beans he was using, so i don't think it's a bean issue.

A few investments I'm looking into are going to be a naked portafilter, and a La Marzocco double or triple basket. I find there's very little room with the stock silvia basket for dose amounts and errors.

Thanks all for the advice. Will keep you posted on how i'm progressing =)

Sounds like you may have some less than prime condition coffee. Early bonding could be coffee that is too fresh and is producing an excess amount of CO2, or coffee that is past its prime. Does your roaster stamp the valve bags with the roasted on date?

I believe the Silvia comes with the OPV set pretty high as well but without a portafilter pressure gauge you cannot reliably adjust it.

Breville Website

Used a Thermoblock Heat Exchanger instead of a boiler. I think it's probably one of the least expensive machines that actually had this feature at a $400 retail. Although temperature control on it was pretty bad, it did heat up VERY fast, and had so-so steam performance. you can get decent micro-foam on this machine, but it takes a lot of patience and practice.

Anyhow.. Pulled a couple shots on the Silvia this morning, and they are definitely getting better. I've been pulling into shot glasses to see exactly how the crema progresses, and it's looking very good. Guiness effect and all, if not always the right colour. Flavour is improving as well.

Zin1953, I think it was probably a thermoblock - sometimes confused with HX.

Without spending the money on a PID you might want to think about the "mini" mod that i mentioned above. You do not have PID control over your temperature, but if all is done right you will be pulling shots at least with consistent temp at the top of the boiler. Temp coming from the group head will vary a bit, but at least it is a cheap way to actually see what is going on temp wise.

The dig thermometer i used had a swiveling head. I cut the plastic at the top of the probe off, and was then able to remove the casing for the probe. I then screwed the section of exposed wire to the boiler. I screwed it in-between the two retaining brackets that hold down the thermostats.

This has been working great for me. My problem now is trying to figure out what temperature reading at the top of the boiler gives me the best shot quality. Still getting a little bitterness/sourness on most shots though.. But the shots i pull are consistent. Just not consistently great...... yet.

-Donovan

You'll forgive me, but a change from the Breville to Silvia is little more than a lateral move.
Certainly no 'upgrade' in terms of ease of pulling shots.

Some, not all, Rocky's are no better than a Breville or Capresso in terms of grinding for espresso.

If you can find someone local with a known decent espresso grinder, say Mazzer Mini, Compak K3, Macap M4 or better you will have at least half a chance with the Silvia. Try the Rocky with an e61. It may not be capable.

From your first post, the grind is too coarse and too much.
Grind finer, use less and tamp lighter.
Bonne Chance.

The rocky is perfectly capable for espresso. You have every chance of making good shots with that combination of machines, as thousands of people all over the world do every day

Your description sounds like old/badly roasted coffee, perhaps try an internet source? In the meantime grind finer, but stop worrying about tamping: tamp light/tamp hard it doesn't make any real difference "how much" so long as you're consistent.

Also, are you giving your Silvia a good warm up? 45-60 minutes minimum with the portafilter in place. Easy temp surf for (newer) Silvias: When ready to pull your shots, run the pump til the boiler kicks in. When the light goes off, run enough water through until it stops hissing to steam, then pull your shot. That'll put you ballpark for most coffees.