Listen for this noise at 2Q: (from the Baratza channel on YouTube)

On an off chance getting to the issue, but did you check the pressure your silvia is using?
If that is too high you need to grind very fine, can you compare your current ok grind in another machine?

Thanks for the video. I've tried the same manoeuvre on my grinder and there is no audible difference. Seems like I can calibrate finer some more.

@Marcelnl,

I'll investigate how to check my Silvia pressure. However, I think I've got the problem sorted as my current calibration is getting me the extraction times I'm aiming for. Although I'm at the limit for fineness, so I'll calibrate finer on my next batch of beans. I'd rather not have to dial in my current beans again, as they are working well with my current settings.

Thanks!

One thing that does puzzle me is that the narrator on the calibration video states that the burrs are definitely touching in the 1A range. I would have expected this to damage the burrs. Is this not the case, or is it expected that you never grind that fine, once properly calibrated?

You're expected to have beans in the grinder when grinding - which gives lubrication.

The ceramic burrs can handle some contact. The contact surface is flat IIRC

The other (older?) spec is to have that 2Q noise at 1M - which is still the Forté spec.

I had the 2Q spec in mine from the factory - but switched to the 1M spec when I put the steel burrs in - the noise when the steel burrs rub is quite painful.