Unsure about Rocky true zero point and espresso setting

[ScottS986]

Hello all,

I just got a Rancilio Rocky. I'm wondering if it's acting the way it should?

For true zero, I've found it to be at 0 if I just turn the hopper until it meets resistance with the motor off. With the motor running, I hear a sound start at 2. So I'm not sure which of these is really true zero?

I'm happy with the shots I'm making with Barefoot Bigfoot Espresso, but I'm making them at 2 (so depending on which of the above is correct, it's either 2 clicks above true zero, or right at true zero.

My concern is that even thought shots are good right now, I couldn't grind finer if need be. Has anyone else experienced this?

Thank you for your thoughts and opinions.

-Scott

[gabriel]

I had similar problem with my old Rocky, after I opened it I found out that there was a crack on the threads preventing them from locking all the way in
Please check this post
http://coffeegeek.com/forums/espr...ines/286631#286631
I posted two pictures of the crack in the middle of the second page

You can try opening your Rocky and after cleaning the burrs and the threads take a look inside and make sure there are no broken parts

/gabi

[HB]

For true zero, I've found it to be at 0 if I just turn the hopper until it meets resistance with the motor off. With the motor running, I hear a sound start at 2. So I'm not sure which of these is really true zero?

Jeff documented the steps in How to find the Rocky true zero point. It's odd that the burrs chirp at 2 but turn easily past that setting when the grinder is off. I agree with Gabi, I would remove the upper burr carrier to check for something odd. Once you screw the carrier back in, you can recheck the zero point easily and accurately since you'll know for certain the chamber is empty and there's no safety screws inhibiting the rotation.

I'm happy with the shots I'm making with Barefoot Bigfoot Espresso, but I'm making them at 2 (so depending on which of the above is correct, it's either 2 clicks above true zero, or right at true zero.

My concern is that even thought shots are good right now, I couldn't grind finer if need be. Has anyone else experienced this?

I sold my Rocky years ago, but IIRC, the only coffees that approached +2 were decafs pulled as ristrettos. In other words, that's a very tight setting. Normal settings for ristrettos were in the +5-7 range. Since you say the shots are good, my guess is you either prefer very tight ristrettos, your zero point estimation is off, or something funky is going on as Gabi suggests.

PS: Many of our members frequent multiple coffee sites. Please avoid cross-posting your question, or mention the other site(s) to avoid repetitive responses (link).

[ScottS986]

Thank you for these suggestions. I will open it up and see what's going on. That won't void the warranty, will it?

Also, I wasn't sure which safety screw you were talking about that could potentially be preventing movement (the finger guard ones?) but perhaps this will make sense once I open it.

P.S. I have removed similar question on other forum.

Scott

[Randy G.]

That won't void the warranty, will it? Also, I wasn't sure which safety screw you were talking about that could potentially be preventing movement (the finger guard ones?) but perhaps this will make sense once I open it.

There should be no warranty problem. What if you ground up a rock and had to change the burrs? If you did not damage the grinder in the process, there would no warranty problem... Really, how could they tell?

The screw in question will be revealed when you remove the hopper. The screw protrudes from the bottom. Remove it and you will not have to remove the three hopper/finger-guard screws again as the hopper can now be removed by unscrewing the entire top assembly- burr carrier and all.

[ScottS986]

Ok, I have cleaned Rocky and set the true zero point as per the instructions above. It wasn't really different. Here's what I found:

With motor off, the furthest I can turn the hopper until it won't turn any more is to 0. With the motor spinning, the chirp starts just past 2 on the way to 1, so the finest I can grind without chirp is at 2.

Setup: Coffee: Barefoot Bigfoot Espresso roasted on 9/15/07, 17g, used WDT and my attempt at Stockfleth, 30 lbs tamp (measured with scale), knock, another 30 lbs tamp, polish. This Silvia has not had the pressure mod done. I measured it to be 11 bar with the water flow method. )

Test results:
Rocky setting 2 resulted in 2 oz shot (including crema) at 25s (liquid after settling for 2 minutes, not including crema 1.6oz)
Rocky setting 4 resulted in 2.25 oz (including crema) at 26s (liquid after setling for 2 minutes, not including crema 1.75 oz)

(I was going to keep moving up the Rocky settings but I ran out of Bigfoot. I switched to another homeroasted bean given to me. At Rocky setting 6 at my 2.5 oz cup was spilling over at 17s.)

Now I was happy with the taste and color of these first two shots, but does this seem like normal shot behavior at the finest setting on Rocky? This almost sounds like what happens when burrs are dull. But this is a brand new Rocky.

Also, I could use a clarification - when the Golden Rule says you should have approx. 2-2.5 oz, are they talking about liquid + crema, or liquid under crema?

Thank you for your advice!

-Scott

[Randy G.]

With motor off, the furthest I can turn the hopper until it won't turn any more is to 0. With the motor spinning, the chirp starts just past 2 on the way to 1, so the finest I can grind without chirp is at 2.

I just tested mine again:

-Currently grinding for espresso at 22 - thick, rich pours
-With motor running, first light touch of burrs at 17
-With motor running, first heavy touching of burrs at 16
-With motor off, the furthest I could get it to go was down to 5

So from the "traditional" zero point of Rocky (burrs just touching) I am grinding at about +5 or +6.

Setup: Coffee: Barefoot Bigfoot Espresso roasted on 9/15/07, 17g, used WDT and my attempt at Stockfleth, 30 lbs tamp (measured with scale), knock, another 30 lbs tamp, polish. This Silvia has not had the pressure mod done. I measured it to be 11 bar with the water flow method. )

The 11 bar is high. That's equal to about 160 psi which could definitely be contributing to the difficulties you are having. Check the accuracy of the gauge you are using and go from there. You are around 30psi (two BAR) over the recommended pressure. If I ran Rocky down to +3 it would choke the Vibiemme which is currently set at about 9.8 bar which gives about 9.3 BAR or so at the portafilter... I think. Certainly a lot less than 11 BAR!

Test results:
Rocky setting 2 resulted in 2 oz shot (including crema) at 25s (liquid after settling for 2 minutes, not including crema 1.6oz)
Rocky setting 4 resulted in 2.25 oz (including crema) at 26s (liquid after settling for 2 minutes, not including crema 1.75 oz)

Two clicks on Rocky should be equal to about 6 to 8 seconds (or more) of pull time.

Now I was happy with the taste and color of these first two shots, but does this seem like normal shot behavior at the finest setting on Rocky? This almost sounds like what happens when burrs are dull. But this is a brand new Rocky.

It doesn't sound like normal behavior for Rocky, nor for Silvia. Something is going on here that isn't quite right. Not necessarily saying it is the equipment, because from these symptoms it could be a lot of things.

Also, I could use a clarification - when the Golden Rule says you should have approx. 2-2.5 oz, are they talking about liquid + crema, or liquid under crema?

Liquid and crema together. Although in my case, at least when using the bottomless portafilter, it's about 2 full ounces of crema in about 25 seconds!

At this point, I would suggest having someone over who knows espresso and see if their results vary at all from yours.

[jesawdy]

Also, I could use a clarification - when the Golden Rule says you should have approx. 2-2.5 oz, are they talking about liquid + crema, or liquid under crema?

My interpretation is crema + liquid, but the crema will fall and it will vary with different aged coffee and different coffees/blends.

The Golden Rule isn't so golden, so feel free to explore lower and higher volumes as well. For example on shot duration, it depends on who you ask, some folks say the time is from first drops, some say from the time the pump is turned on.

An interesting way to look at the shot is by weight, not volume, see Brewing ratios for espresso beverages.

[ScottS986]

Randy,

Thanks for taking the time to test your Rocky again. I'm going to do the Silvia pressure mod this weekend and see how it changes things.

-Scott

[ScottS986]

Well, here's the end result here. I did the Silvia pressure mod, which required one washer + another one filed thinner, and tested the pressure with a gauge so it was at 9 bar w/o flow and and 8.5 bar w/controlled flow. I still could not choke the Silvia. I even tested it at 6 bar - still no choke. So I went down to Peets and had them grind me up some beans for Turkish, which felt like cocoa, as opposed to Rocky's fine sand. This did indeed choke Silvia. Since Rocky is grinding as fine as I can, (two notches away from the burrs touching with the motor off) and can't choke Silvia I think that indicates that it's just not able to grind as fine as it should. So I'm returning it under the 30 day buyers remorse. I could get another Rocky, but I think I'll just go for the Mazzer Mini.

Incidentally, when doing the pressure mod, I knocked the steam thermostat which dislodged it from the thermal mastic sticking it down to the boiler. (It's still held down by the harness. The boiler seems to behave as it did before when steaming (boiler on until around 280, then back on again when it gets down to around 255). Do you think it's necessary to reapply the mastic?

Thanks,

Scott

[gabriel]

Well, here's the end result here. I did the Silvia pressure mod, which required one washer + another one filed thinner, and tested the pressure with a gauge so it was at 9 bar w/o flow and and 8.5 bar w/controlled flow. I still could not choke the Silvia. I even tested it at 6 bar - still no choke. So I went down to Peets and had them grind me up some beans for Turkish, which felt like cocoa, as opposed to Rocky's fine sand. This did indeed choke Silvia. Since Rocky is grinding as fine as I can, (two notches away from the burrs touching with the motor off) and can't choke Silvia I think that indicates that it's just not able to grind as fine as it should. So I'm returning it under the 30 day buyers remorse. I could get another Rocky, but I think I'll just go for the Mazzer Mini.

Scott

Scott,
The Rocky should be able to grind fine enough to choke the Silvia unless something is wrong with it
On a used grinder I would try and replace the burrs
With your grinder I still suspect that somehow the grinder is defective
Did you check for holes on the threads holding the burrs ?
They should be easy to spot once you clean the burr - they will stay dark as the grinds stick to them

/gabi

[ScottS986]

Hi Gabi,

The grinder was brand new. I did notice some threads where a lot of grinds stuck to them, but it was more like all the way around the thread. I have read of others having some buildup of grinds at one level of the threads. If a Rocky is supposed to be able to grind for Turkish, this one can't.

-Scott