My silvia is about 3 months old and has been working pretty good, recently I did my first back flush/descale then my troubles started. No matter how hard or soft I tamp, no matter if i tamp harder on the opposite side of the portafilter handle I always get what seems like tunneling meaning the shots always start coming out of the opposite side of the portafilter handle (closer to the machine wall) and very watery on that side always, I'll post a video tomorrow to show it with couple of different scenarios. Figured i'd ask if anyone is having this issue and if you have a solution.
Pictures of the puck/coffee
https://drive.google.com/open?id=0B1WF2 ... EQzTTJaVmM

I would try to dose 1gr less, grind a little finer and compare the result.
Sometimes overdosing cause this kind of channeling.

- Tamp harder, grind a bit more coarse to compensate. I think a big part of the problem is that you are using too-fine of a grind which can lead to problems as you are experiencing in the extraction. Have you measured the tamping force? Your tamp looks quite "gentle."
- I do not remember my dose with Silvia. That was a long time ago. Have you done the nickle test to check to be sure you are not over-dosing?
- Do you need to WDT? Looking at the distribution, and looking at the coffee after tapping the portafilter downward, I would say no. Tap the PF downward with more force to settle and level the coffee and just tamp it downward harder and be done with it.
- Why the "twist" of the tamper? My point being that all procedures need to be examined. Simplify. The less you do the lower chance of creating problems.
There also appears to be a 'fissure' across the tamped coffee, somewhat across the coffee from about 10 o'clock to about 3 o'clock before the extraction.

Hi there,

I would try to remove the shower screen to clean it. You can soak it in the product you are using to backflush and then use a brush to clean it. Also check the machine to be properly leveled. The Silvia's pump tend to give a blast in the beginning of the infusion, so distribution/tamping issue can cause that kind of problem if the puck is not soaked enough (screen cludged...) and it always will be where the screen is cludged. Since you are not tamping hard, the problem can be worst. So I suggest you to clean the shower screen, level the machine, tamp harder and dose less. I would suggest tamping harder first though...

Also, the Vario is a good grinder enough to forget about the WDT distribution, I think. Since the retention can be about 2-3 grams left in the grinder, if you weight 18g of raw beans, you may have only 15-16g in your basket, so I suggest to tare the basket and weight the final grind in it, not the beans. Your shots will be more accurate each time and it will be easier to troubleshoot problems in the future.

Silvia loves headroom between the puck and the screen, and hard tamping: the worst thing you can do is updosing it and be too ''gentle'' on the tamping.

Give us some news about it !

Thx for the infos! Here is a video of just extraction, i added about 16.5g of coffee and pressed a bit harder with higher temp.

What is your basket capacity ? Baskets are designed to produce a better extraction at +/- 1g of their rated capacity, so this is something good to know when dosing and should be the first rule to follow.

The second one considering dosing should be your taste. Make three coffees with 0.5g difference in the input and see what you like the most. Then, you can adjust the dose by 0.1 increment to find the sweet spot of what you want to get. Somethimes 0.5g will change nothing, but when you are near the sweet spot, 0.1g can make a huge difference. Adjust other parameters (grind, tamp) to suit your needs.

Once you get your dose, lock this parameter and have fun with infusion time and brew ratios.

Use the 14g basket that came with Rancilio, I also have the 18 and 22 but I prefer the 14g specially when dialing new coffee to avoid wasting. I was using 15.7g on the 14 and was not consistent enough with this italian coffee beans I'm using then went up to 16.5 gradually seems the extraction is perfect and taste is richer, this is the only coffee that when grinding comes out fluffy almost flaky compared to other coffees I've used.. idk if that means anything.

I am no expert but It appears you are putting too much of a dose in there. Also I have found when I grind the last of my beans in the vario, the lack of weight on top of them (by other beans) makes the grind different. So you may have different sized grinds in there.