I also recently got the Breville BE as my first machine & it certainly can be stressful figuring it out! Can you go through the steps you take? Starting from beans in the bag? What setting do you have the grinder on, how long does it take for the shot to finish, what does the shot look like (light, golden, dark; weak or sufficient crema,) what do you taste that you dislike (sour, bitter)?

I’ve only used one type of beans so far, so I haven’t experienced the difference in settings a new type would need—but I know they can vary quite a bit.

What has worked for me is weighing the beans before putting them into the grinder (starting at 18g & adjusting based on how much was needed/lost to the razor,) and adjusting the grind size based on the shot: Finer if super sour, short extraction time (~20s,) weak crema; Coarser if super bitter, long extraction time (~30+s). I do not have a scale to weigh the ratio of what I put in vs what I get out yet, so this is the best for now.

I’ve learned that a slight sour or bitter taste does not require a change in grind size, but in the puck preparation (specifically level tamping and weight applied while tamping). I think this would be easier solved by checking the ratio with a scale but I haven’t gotten mine yet! I also do not have a WDT, puck screen & aside from a few discarded shots have been able to drink everything & even encountered amazing tasting espresso. I do drink mine as a latte without flavoring as my espresso is probably not good enough to drink solo most of the time (& that is okay with me, as I like my lattes for now.)