Thanks all for the advice - I'd thought about the puck being too tight until it cracked, except I'd started coarser and it just came through fast, but from the very start. Will try take a few steps and go from there. Also not seen traces of channels in the pucks, but that's far from scientific...
And yes, it's an automatic machine, a Gaggia Classic 👍
I had the same issue recently with some Dark Arts, one step coarser on my grinder seemed to solve it.
I've got the 9 bar spring in, a puck screen, and an IMS precision basket and shower screen BTW
Thanks all for the advice - I'd thought about the puck being too tight until it cracked, except I'd started coarser and it just came through fast, but from the very start. Will try take a few steps and go from there. Also not seen traces of channels in the pucks, but that's far from scientific...
And yes, it's an automatic machine, a Gaggia Classic 👍