NW9 Great post!
What roasts do you mostly like ? Not sure I got that from your post. I would stick to 2-3 beans and familiarise first. Jake’s recommendation of the North Star is excellent. Their “The docks house” blend is also very good. So is, the Blackcat’s easy to dial Chocolate Point.
NW9 When I went finer and ended up with shot times closer to 40s-45s then the pour looked a lot better and the taste was certainly better in that the astringency was gone. However, I found it often tasted a bit bland at this point (perhaps over-extraction?) as there was not much acidity but also no sweetness. I’d then usually try and reduce the ratio which sometimes gave some success.
I won’t worry too much about the shot time, unless it is too fast or the cup doesn’t taste good. The 30s-35s is the typical shot time for 1:2. You can pull longer at 1:2.5 and see if it suits your palate. I always pull 1:2.5 if on the lighter side and 1:2 of medium.
Your bland taste could be because the beans haven’t degassed yet or stale beans or may be stuck oils on your portafilter or not cleaned shower screen.
How often do you clean the shower screen and portafilter? Do you get a lot of foams on the shower screen after the shot? How do you store them?
Over extraction, IMO, unlikely to cause a bland taste. If the pour is good and the grind is tighter, it might taste bitter. How long do you rest the beans? You could also try tamping lightly and see if it improves. I don’t load more than 16.5g on the IMS basket; and 17g is max and rare if it is really a light roast.
As tompoland said, please share a clip. Thx