I know this subject has been beaten over the head many times and I've done a ton of research related to off flavors but it'd be nice to get some fresh input. So a little background first I've got my brewing process dialed in and all my beers taste great going into the keg but after being force carbonated they take on a very faint plastic taste and in the case of my last beer a mellow astringency. The last beer brewed was a Hefeweizen that fermented for two weeks and had great banana and clove flavors from the yeast but after it was kegged and forced carbed at 30psi for two days, these flavors became muddled and almost watery and I could taste faint plastic and little bit of an astringency. My thoughts are could be infection, gas/beverage tubing, yeast bite, or green beer that needs to mature more in the keg? Also I've never scrubbed my dip tube and just soak it or turn up the pressure inside keg and run PBW and sanitizer through it at a high PSI. What are peoples thoughts on changing out CO2 canisters in a draft system is this necessary? Is cleaning the regulator something you do before hooking it up to CO2? Any input is greatly appreciated