Hi Bon, Actually, one of the biggest problems I've had to overcome that directly affected the taste, was my dose and distribution. For a long long time I thought it was the cooling flush, that my machine was rebounding to too hot too quickly, that my boiler pressure was too high ... But lately I've been focussing on my dose and distribution. If you're getting bitter ashy shots, watch the streams coming from the spouts. If they're thin and slow and you end up with a short ristretto, you're probably updosing too much. Once that naked portafilter arrives, you'll get to see which parts of the pucks are being extracted, and which parts are just too densely packed ... I'd suggest preparing a shot (grind, dose, tamp), and then insert the portafilter. don't pull a shot, just remove the portafilter, and look at the top of your puck. If some of it is missing, it's now stuck to the shower screen, you've overdosed. I'll tend to dose to a mound, even out the mound with my finger, swipe the top off, wipe the rim of the basket and tamp. I don't tap the portafilter with the tamp anymore, and I din't polish the surface of the puck by twisting the tamp. I used to tamp with just about all the weight I could, but it seems unneccessary now. Of course, my method works well with my machine. Your grouphead/gasket/shower screen/basket are all probably slightly different to mine, so play with the naked portafilter unitl you find a method that works for you!
