Hello everyone, this is my first post, and I'm hoping I can get some help. I have an issue with my system. Every time I tap a keg the first time, it tastes great. No problems at all. If at any point I untap the keg and retap it, the beer tastes bad. I recently had an issue where I purchased a keg, tapped it, but the new elbow I just put on leaked a bit, so I had to immediately untap it, and fix it. When I retapped it, again, bad beer. I don't exactly know how to describe the taste. It tastes a bit over-carbonated, a little bitter, and the beer itself has almost no flavor. I've let it sit for 2-3 days, same thing. If it matters, the CO2 tank has plenty of pressure, and the keg itself is at about 8 PSI. There is a second keg hooked up to the same system through a dual regulator and everything is fine. In the past, when this has happened, I've emptied the keg, hooked up a new one, and the world is right again. I can't seem to find anything online about this problem. Any suggestions? I don't like wasting all of this beer.