I'm about to throw Silvia out the window!

Beginner and pro baristas share tips and tricks.
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Medic One

#1: Post by Medic One »

Admittedly I am a new Silvia owner and not a veteran. But I have been reading posts all over the web about this finicky machine. Just this morning I pulled 8 shots with a bottomless portafilter, none of which produced a 2 oz. shot longer than 19 seconds. I'm grinding with a Rocky on 3! I'm tamping with over 30 lbs. of pressure. I even recently backed off the OPV 1/2 a turn.

I have been trying different dosing amounts also. When I fill to the rim of the basket and tamp with significant force my puck still contacts the screen. Those shots tend to be fast and blond. So I started to underdose such that when tamped, my puck was below the "crimp spring" ridge in the portafilter basket. While this prevented contact between the puck and the screen it didn't help with my shot times.

I have been able to choke Silvia only twice. It was with a grind at about 1 or 2 and some serious, repeated tamping. I was trying to establish some kind of baseline. But as stated earlier when I back off a bit to 3 on the Rocky, I still get quick pours and LOTS of blond and sour/bitterness.

So here are some specific questions:
1. Without purchasing a pressure reading portafilter, how can I tell if Silvia is simply running too much pressure?
1a. How many turns of the OPV valve with make meaningful pressure changes?

2. Should I continue to dose such that the puck doesn't touch the screen?

3. Is it reasonable that I'm grinding at 3 (This is true 3. It's 2 on the dial and 3 clicks back from burr contact) and still getting quick pours?

Thanks for the help. I don't think that repeated sips of terrible pours is helping my patience any. I'm taking a break. :oops:

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gadflea

#2: Post by gadflea »

I'm sure this is the first question any member here will ask: what beans are you using? When I first bought silvia I used starbucks beans until I could get fresh beans from intelligentsia. The results were atrocious and similar to what you have described. Fast shots are symptomatic of stale and over roasted beans. I also find the stale beans contribute to side channeling, another thing that could be causing the fast pours.

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Medic One

#3: Post by Medic One »

I was going to include comments on all the variable, but didn't want my first plea for help to be a novel.

I was using some beans that my wife picked up at a small local coffee shop chain in Gig Harbor, WA. They are getting close to two weeks old. I was using them to practice picking a grind setting. When I thought I had things dialed in I switched to Vashon Coffee (roasted in Vashon Island near Seattle and used in several coffee houses) which was roasted 7 days ago.

I was very excited. I was using the bottomless. I underdosed. I "declumped" with a fork. I did a couple light taps on the counter to settle the grind. I did a moderate first tamp, then a light tap on the portafilter side with the tamper. Then it was the final heavier tamp and polishing spin. Onto the Silvia...... I was off to a good start with darker color quickly forming a long, centered cone leading me to think I had good distribution without channeling. But it quickly turned blond and only took 15 seconds to get 2 oz.

I'm not a weak man. I've got to think I'm tamping sufficiently hard. And I'm grinding at 3. What is up? :?:

Grant

#4: Post by Grant »

You said this was a new Silvia?

If so, it should have an adjustable over pressure valve (OPV). Without a gauge, it is difficult to set to an exact value, but when I had my Silvia many, many moons ago, I found getting a decent shot almost impossible with the factory OPV setting.

Reducing the brew pressure hitting the puck made a HUGE and instantaneous difference in shot quality. I, like you, was not sure what I was doing wrong, and I spent a lot of time (and money) on everything from tampers to beans, and in the end, reducing the brew pressure was the ONLY thing that made any difference.

So, even just "winging it" it is possible to get in the ballpark of 9 bar - make sure you make note of the factory setting and do everything with the machine cool and unplugged - make small changes, and test often. The way I did it was to insert the blind filter, and start the pump (don't run it too long - only bursts of around 10 seconds with rest time in-between!). Watching the return water line to the reservoir, I adjusted the OPV (at the time by using copper washers), until I was getting a light, but steady trickle back out of the OPV into the tank.

To this day, I still have no exact knowledge of what the pressure setting was, or was changed to, but I just let my taste and shot quality guide me.

Moving later to a machine with a gauge/etc. then proved to me I was close as well.

Of course, you could always purchase a PF with a pressure gauge.
Grant

User avatar
gadflea

#5: Post by gadflea »

Here are a few things to consider:
1. Your tamping routine sounds a little overzealous. I would suggest doing away with the light tap on the portafilter side because that can break the puck's adhesion to the basket and lead to side channeling. The fact that you describe yourself as "not a weak man" leads me to think you may be tamping too hard. It really does not take much pressure to get a good tamp.
2. Did you buy Rocky used? If so, the burrs may need to be replaced. I don't know for sure that this is your problem, but it seems weird to me that you are grinding three clicks above the burrs touching and still get <20 second pulls. I have never seen burrs that are worn out so I do not know how to tell you what that looks like. Just a thought.
3. Finally, look at this article for further suggestions on tamping and extraction problems. /naked-extraction.html

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Medic One

#6: Post by Medic One »

Thanks for the ideas...

I stuck a blank into my portafilter and pumped for around 12 seconds and observed a continuous flow of water out of the return line. As mentioned before I have already "backed off" the OPV 1/2 turn. I'm right aren't I? Counter clock wise is less pressure, right?

I also disassembled the Rocky to check the burrs. I removed the top burr ring and it feels pretty sharp. Not like a razor but I could see cutting your finger with a little pressure. I also double checked the zero point by screwing the top burr ring all the way down until I couldn't spin the lower burr ring. I then backed off just enough to allow some rotation but with audible contact. Returning the bean hopper and step indicator puts my true zero point at -1.5 (although there is a "protection" screw that won't let me actually reach that zero point).

So unless I want to, or should, back off the OPV even more (advise?) I guess it's down to beans and technique.

I'm going back to filling the basket up to the rim then brushing off with a flat edge. It sounds like that is more the norm around here. I'm also going to focus on drying the basket REALLY well prior to adding coffee.

What say you about the tap, tap, tap on the counter to "settle" the coffee prior to tamping? And what about a medium tamp, polish then harder tamp?

thanks

User avatar
gadflea

#7: Post by gadflea »

I have never adjusted the pressure valve on my machine so I don't have any advice there.
On to tamping... Rocky produces clumps so I suggest stirring with a needle to break up those clumps. After stirring, tapping the portafilter to settle the grinds should be unnecessary. On the other hand, I don't think it can hurt either. I always use a very light (as in no downward pressure), four-corner-tamp to get the grounds off of the side of the basket and then a single firm tamp and light polish.
Tamping methodology is kind of a personal thing. What works for me may not work for you. Experiment with different techniques, change only one variable at a time, and eventually you will figure it out. You may also want to order a bag of beans from one of the tried and true site sponsors like Counter Culture or Intelligentsia just to be sure that the beans are not your problem.
Good luck.

djmonkeyhater

#8: Post by djmonkeyhater »

Something sounds not right here.

I use a newish Rocky everyday with a single group small commercial machine (Faema Compact). It's had less than 100lbs of beans through the burrs and we will choke that machine or a number of other machines I've messed with if we run it under 9. This is almost independent of the bean. When we get new beans, it goes up to maybe 12 and down to 10 by the end of the week.

I was even messing with a machine that had the pump running at 13 bar and the OPV semi-disabled and the puck stalled the pump. Rocky was not set under 10.

User avatar
erics
Supporter ◈

#9: Post by erics »

Medic One wrote:Without purchasing a pressure reading portafilter, how can I tell if Silvia is simply running too much pressure?
Unfortunately, the majority, if not all, of the PF's you can purchase with pressure gages are lacking a quality pressure gage. You would be MUCH BETTER off by building your own. Do a search on this site for "pressure gage" or "portafilter gage".

Alternatively,

Measure the flow in the return line using a pyrex cup while pumping with a blind filter. With a stop watch, time how long it takes to go from the 2 oz mark to the 6 oz mark or 4 oz to 8 oz etc, etc. You'll come up with 4 ounces in "X" seconds. "X" should be between 27 and 28 seconds. Adjust the OPV as necessary to get this time.

This will give you very close to 9.0 bar blind filter pressure and about 8.5 bar with a normal double-shot flow.

Practice your tamping with a bathroom scale - 20-30 lbs force is fine. The idea is to be level and consistent.

A digital scale could be one of your best accessory tools.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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civ

#10: Post by civ »

Hello there:
djmonkeyhater wrote: Something sounds not right here.
I have to agree.
As of late and after a couple of years or so of very consistent shots of very good (to me, of course) espresso, all of a sudden I had a number of problems with my rig. And very much like the ones you describe in you post, medic_one.

The possible culprits I searched for evidence were:

1. temperature settings and/or PID
Went through a whole range of different temps.
Checked the PID probe, changed the home made TC for a Pt100, just in case.
No dice, outside probe in boiler and PF certified everything temp-wise was OK.

2. the rotary pump gone south.
So I took it offline and put the Ulka with the OVP back in.
No dice. Manometer sings the right tune before boiler and at PF.

3. grinder settings.
They had not been touched with the exception of the ocasisonal notch up/down for special weather days.
Tried a small range, ground a lot.
No dice.

4. the burrs gone bad all of a sudden.
I took the grinder apart, cleaned it and adjusted all screws, They sure didn't look bad but still I started looking up prices of new 80mm burrs. Started using a spare grinder with smaller 64mm burrs.
No dice. This smaller grinder even clogged up a bit.

5. so all the burrs in the house had gone bad all of a sudden ...?
No.
Wait a seco ...
Can't be.

Could it possibly be the coffee that my usual purveyor (from more than two years now) swears by his mom and grandmom had been roasted just a week ago?
Nah !
The lack of that characteristic aroma on grinding should have warned me, but this guy was highly recommended.
I called him up, complained, sent the stuff back and got another batch in exchange, as 'fresh' as the one I sent back, of course.
No dice.

So just I went to another supplier and got myself a bag of Italian coffee (1Kg. bag Segafredo Premium, 25% more expensive than what I had been buying) and bingo !!!

The first shot was perfect.
No adjustments to temp, grind or pressure.

The bottom line?
It's usually the beans.

See here:


Note to Self: It's the Beans, Dummy!

Hope you get things sorted out.
Best regards,

CIV