Rancilio Silvia - Can't get the same results twice

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by Maxcheese »

Hi guys!

I've been trying to find the optimal sweet spot for shot weight/timing. I'm using a VST 18g basket filled with 18,5g and I'm going for 1:2 in 27ish seconds. I try to eliminate anything random to be as precise as possible.

I'm single dosing (Niche), I do WDT. Machine is a Rancilio Silvia and I'm also using a Force Tamper to be as flat and precise as I can be.

However, my shots keep getting all over the place, varying from 30ishg to even 40g.

I can't figure out what I could do to be more precise... The only thing I can see is the machine?

I calibrated 10 bars with the homemade portafilter gauge so should be 9ish with a puck.

Any pro advice??? :)

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#2: Post by Jeff »

I'm not sure what you're keeping constant that the shot weight is varying. I'm assuming it is time.

Is your first shot of the day always heavier/lighter than the second and subsequent shots in the day?

Have you checked the headspace?

How are you managing the Silvia's temperature?

Maxcheese (original poster)

#3: Post by Maxcheese (original poster) »

Silvia is PID'd. It's alway fully heated and I'm flushing the headgroup before every shot. Headspace looks quite allright, no imprints on the puck.

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#4: Post by baldheadracing »

These are a bit out there, especially with a relatively new machine like a v6, but ... two possibilities:

1. Your OPV could be failing. Watch your portafilter gauge to see if the pressure is constant.

2. Your three-way solenoid could be leaking:
a. dry out your drip tray
b. pull a shot without the drip tray grate in place
c. during the shot, watch where the tray is under the machine. That's where the three-way valve dumps water at the end of the shot.
d. See if any water comes out into the tray during the shot. If so, then your 3-way is leaking.
e. At the end of the shot, there should be a blast of water into the drip tray. If there's no blast or only a dribble, then your 3-way circuit needs cleaning.

You could also try not flushing and see if that makes a difference.

Good luck!
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada


#5: Post by Tseg »

I've had a v6 with PID for about 6 months. I had similar issues. I use a Baratza Sette 270wi grinder (grinds to exact weight +/- .1g every time). Step 1 to fixing was getting a naked portafilter at which point I found the time for my drip to condense to a single stream was all over the board, thus, my output varied constantly +/- up to 8 ml per shot (sometimes more). Now I rake, level and calibrated tamp and my tamping result has significantly improved consistency how long 1 stream takes to form (~3 seconds). My Sette has like 20 settings and then 8 sub-settings per setting for grind size, so somewhat infinite and precise settings. I buy a 1 month bean supply. During 1 month I generally have to tighten my sub-setting up to 6 notches to deliver desired shot weight per constant pour time as output increases over the month at a specific grind selection. Every new bag I have to immediately make more more coarse again by 6 sub-settings. Also, EVERYTHING changes between types of coffees, so I find myself sticking with 1 roast for months to master its grind calibration requirements. So this 6 sub-setting variance accompanying bean age is for the bean I currently use, and could change for a different bean. In summary, I have really dialed in my v6 consistency, but it took months of discovery and fine tuning. BTW, early on I adjusted my OPV valve to 9 bar... if you adjust that all your historical grind calibration data goes out the window. The journey has been a bit a labor of love but I finally am now very pleased with the output and consistency... and smile as I reflect upon how many undrinkable shots I discarded in the early days.

Supporter ♡

#6: Post by Pressino »

I didn't see where you said what the interval is between the successive shots. Is this variability from day to day...e.g., this morning you make an espresso and tomorrow you make another one? Or with back-to-back shots? Or shots separated by an hour or so, etc.?

Assuming that your dosing and puck prep is truly consistent and that you are using exactly the same coffee, there can be different causes of inconsistency depending on the interval between shots, some of which have to do with the machine and some with the beans. Day to day differences are likely due to changes in the coffee that occur after roasting. Generally, you need to grind finer as roasted coffee "ages." This may require changes in dose weight/volume and perhaps tamping pressure as well as grind level to maintain "consistency."

Very short "back-to-back" shots may not give the machine time to maintain a stable brew temperature (no matter what the PID readout says). Also, the boiler fill level does vary between the "on" and "off" fill probe sensor intervals.

Maxcheese (original poster)

#7: Post by Maxcheese (original poster) »

I was wondering if you guys out there using a Silvia have any inconsistent results. Whatever I do, it seems I can't get the same result twice.

I have a niche zero and single dose everytime. I do WDT and tried with many tampers (regular, force, calibrated). My machine is in pristine order and pressure is a stable 9 bars, tried to play around with this as well. Grounds are fresh and ground to order. Whatever I do, I end up with a more or less 5 sec. difference for a constant 2:1 ratio.

I'm I just expecting to much or my machine or I'm I just lacking skills here?

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#8: Post by baldheadracing »

Just wondering - what do you mean by a five second difference? For example, do you mean that the shots range from 25.5 seconds to 29.5 seconds (27 seconds +/- 2.5 seconds) - which, while not perfection, is reasonable - or that the shots range from 22 seconds to 32 seconds (27 seconds +/- 5 seconds)?

Mod note: I've merged the content from your prior thread.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada