Please help! I have all the fancy espresso tools and a nice grinder, but I have no idea why I don’t get an even flow out of my machine. I have a Niche grinder, I use a WDT tool to distribute the grounds, I use the Normcore distributor, and a normal dose tamper. I replaced the shower screen on my espresso machine with the VST screen and I’m using a VST 18g basket with a puck screen. I am pulling 40g shots in about 28 seconds, so I believe my flow rate is right, but I can’t figure out what I’m doing wrong!
I'd consider upping the dose and grinding a little coarser til you hit the same time, and also pre-infusing at a lower pressure until the first drops form on the bottom of the portafilter. You could also try that independently if you're not doing it already. Good luck!
Also, does it eventually fill the screen and form a single stream? If it does this for like 5-15 seconds and then steadies, that could be totally normal and I wouldn't worry about it if it tastes good.