We get a lot of questions about bottomless portafilters and getting sprays or little jet streams coming from different directions while pulling a shot. This is a common so if you experience it, don't worry, even top barista at your local shop does from time to time, even if they won't admit it. We call this channeling. Channeling is frustrating and affects flavor by resulting in a very sour and/or bitter shot, not to mention the mess it leaves.
If you are nodding your head in agreement because you know exactly what we are talking about, we wrote a journal entry all about this using information and techniques from some of the industry's most respected baristas. Click the image below to check it out and chase those perfect shots.