There is a lot of variables that interplay with each other when extracting coffee at such high pressures. But the first thing you've already realized with the bottomless portafilter, is that not only are things different, but what you were doing before was always causing channeling and sprays, but you just can't see them on a spouted portafilter as easily unless you know exactly what you're looking for in the stream. Normally I believe most people would say this boils down to a distribution problem (try looking up WDT, stockfelths and schomer techniques for places to start), but also look at your dose as I believe Miss Silvia is quite temperamental when it comes to the amount of coffee in her basket.

Given all other variables are the same, just increasing the amount of coffee will require a more coarse grind to keep shot time the same. At the same time, because you might have a different basket geometry, or the holes might be different between the double and triple basket, this might not always be a hard rule or work in the proportions expected.

The main thing is, have you tried to change the grind in the direction you expect? Did it not work for some reason? Don't be afraid to pull some sink shots and dial in that beast. As much as perfect coffee each time is really nice...to bring your coffee to the next level sometimes you have to experiment a little. Often you find out a really obvious mistake, but you probably have been overlooking it this entire time.

Good luck

gj91 wrote:I have had the Silvia for probably 7 years now.

gj91 wrote:I'm doing too many sink shots, I guess I need more practice.

Er, it's been 7 years and you need more practice?!? Sorry, something is fundamentally wrong.

Hi Jim,

I have the Silvia for one year now and I did some modifications on my routine last week, to resolve channeling problems. I thought my tamper was in cause but finally discovered I was tamping unleveled. So I'm paying more attention to it and get a little improvement.

I was suspecting, as you were, the pressure was too high (now I know it was around 9.5 bar). So I set the OPV based on volume and get a dramatic change in taste. But most shots were tasteless. I had the chance to get one gauge and fitting to match the portafilter and checked the pressure. It was 8.2 bar. I brought it back to 9,0 bar and the taste is very good.

I was used to dose 14 gr in the Rancilio basket. I overdose to 15 gr and even 16 gr and THIS made a huge difference with the channeling problem. I suggest you try this. Since I use the Rocky doserless grinder, I need to do the WDT. To help the grind settle in the basket, I gently tap the PF on the counter before final distribution. This made my best shots ever.

I will get my naked PF shortly, I'll let you know if I see a difference between both.

Channeling means you get one stream for a while out of two spouts? It is caused only by an unleveled tamp?
I have the 2009 silvia and i am considering buying a naked portafilter.

CUBANERO wrote:Channeling means you get one stream for a while out of two spouts? It is caused only by an unleveled tamp? I have the 2009 silvia and i am considering buying a naked portafilter.

Channeling means that the water takes a path of least resistance through the coffee and instead of having an even extraction through ALL the coffee, some water goes through the coffee and comes out more or less like it went in. It can be caused by a number of things including a tamp that is not level or by distribution problems.

If you are using a standard portafilter then there is a good chance that you may only see the very worst channeling effect. This is because the thin, under-extracted channeled water is mixed with the rest of the flow. With a bottomless portafilter you can watch the entire bottom of the basket and see the flow and see if it is even. Additionally, "sprites" are then visible which is another indicator of channeling. Sprites are little jets of spray like what would come from a hypodermic needle used as a squirt gun. These little jets of espresso can spray a number of feet, and usually come out at an angle from the basket. In other words, when examining the flow, and particularly when trying to solve channeling problems, wear eye protection.

The naked portafilter does not change the extraction to any degree of consequence, but it does allow you to see what is going on. I use one all the time because it makes clean up easier and quicker as well as I love watching the show!