Questions to your question
How's it going? I'm going to make this short b/c the last reply was lengthy an the forum timed out before I could submit it. So, I will give a shortened version of a proper shot and then will reply to any more questions. I've been pulling on a Rancilio for about ten years now and believe this to be a good method. First, light roast or European espresso is going to give a much smoother flavor than an American roast espresso. The difference is only in roasting and is about 5 degrees F. Make sure the beans you use are ground for no more than 45 seconds before the shot is pulled. Most expenive machines take about 1 Bar of pressure to properly pull a great shot. Pro baristas generally now concur that best shots are 3/4 to one ounce and are pulled for about twenty-five seconds. Next make sure that your tamper just fits inside the groupo and is very smooth on any part that may touch the ground beans. I believe most people think about 35 pounds of pressure to tamp is sufficient. I judge this by the amount of force my forearm can push down. Leaning on the groupo is way too much pressure. Also, I used to twist the tamp when packing, but have found the best shots are created when only about a quarter or a twist is used. This will create a delicate lattice work for the water to run through (think Plinko from the Price is Right). Using this method, almost every shot I pull is about half creama for at least 15-20 minutes, and have tiger flecks throughout the creama. Hope this helps and please reply if you have any more questions.