Sudden Extreme Channeling [Rancilio Silvia v2]
I’m getting really frustrated with this and am hoping someone else has had the same problem.
I have a DF64, first generation, and a Rancilio Silvia v2 espresso machine. The steam and hot water function of the machine is working as it should, and I'm using 18 grams as specified by my basket. I had my espresso machine for about two months and everything was working great.
But my espresso has completely changed for no apparent reason. The shots are extremely fast, around 7 to 10 seconds. They often spray or channel badly, and generally they’ll build up normal resistance then suddenly the water rushes through. Strangely, adjusting the grind size doesn't seem to have much effect at all. I've tried grinds from very fine to fairly coarse and it all does pretty much the same thing.
I’ve swapped between two new baskets, and have tried tamping by hand and with a calibrated tamper. I’ve made broad adjustments to the grind, inspected the shower screen (it looks okay, though the flow is a little stronger around the center screw), and the espresso machine itself (steam and hot water are fine).
Recently I took my DF64 apart to align and clean the burrs. I was getting the burrs to touch too early. After doing that, the grind became much more uniform and very fine, but it didn’t seem to help. Even on my grinder’s most fine setting just before the burrs touch, water still rockets through.
I use a WDT tool liberally and a blind shaker cup.
I’m trying to work out if the problem is the grinder now having a strange distribution of coffee (too many very fine particles and/or big clumps)? Or is the coffee puck collapsing immediately? Or is it the water not being distributed evenly in a way I can't see? Or is it something else entirely that I haven't thought of. What's confusing me is that changing the grind doesn't seem to do anything. If you have experienced a sudden shift like this where changing the grind doesn't help, I'd love to hear your thoughts.