I've always got a fairly harsh tasting espresso from the Silvia machine. I've adjusted the pressure down to 9 bar. I've played with temperatures, pre infusion, and yields. It doesn't seem to make a major difference. I use either home roasted beans, or stuff from various top roasters. I keep the beans frozen and single dose grind. I always seem to be able to get nice even pulls. I use the same stuff (basket, grinder, and recipe) on a Kitchen-Aid proline machine at our work, and I get a totally different tasting espresso. Much less harsh. Sweeter maybe. More flavor subtleties from different beans. That machine doesn't have a PID, and I don't know what the pressure or temperature truly is.

Machine: Current Gen. Silvia with PID, bottomless portafilter, 18g VST basket
Grinder: Sette 270
Typical recipe: 18g ---> 45g out (usually). I've been all over in the 2:1 to 3:1 range.
Time: 2 second preinfusion, 2 second wait. 28 ish seconds on. But I've gone back and forth with the preinfusion.

Is this typical of others experiences? All things equal (pressure, temperature, grind, baskets) do machines have flavor signatures?

What's your temperature surfing routine?

I have a PID on it. The temperature is set to 216. I've lowered it incrementally as low as 212. Only minor changes in taste. It is also on a timer so that it is thoroughly warmed up when I use it. I still flush it and let it come back up to temperature right before pulling a shot.

nrcoffee wrote:I still flush it and let it come back up to temperature right before pulling a shot.

How long are you waiting for the temp to stabilize after the flush? My PID Silvia typically takes 5-10 minutes to stabilize between shots.
Try flush and go. Don't wait for the indicated temp to come back up. This might help.

Good luck.

Ed

A few minutes. By the time I get back over to it. The PID has stabilized at the set temp.

What do you use for water? Maybe you can bring the machine to your work and pull shots alongside the Pro Line.

I use filtered water. The same stuff I use for pour overs. I have no issues with it for that.

I'm not sure what style of coffees you're pulling but with light SOs I've been having better resutls with up-dosing and shorter etractions.

20g in 18gVST and extracting 30-34g depending on things.

When you pull water through the group do you see any signs of flash boiling? I think with my old Silvia and Auber I had the PID at 210-212, but I can remember.

Thanks for the suggestion. Anything is worth a try. I typically do lighter roasted SOs.

No. No flashing. But yeah, I've adjusted it down one degree at a time. Didn't really notice a huge difference.

You can try lowering the temperature even more. Maybe even down to 200F or so.

Based on the conventional wisdom, you'd expect lowering the temp will make the shot sour and increasing the temp more bitter. But I found that below a certain temp, lowering the temp had the opposite effect of making the shot less sour and smoother, whereas increasing the temp makes the shot more aggressive/harsh and sour. Give it a try to see if it helps.