I purchased a few packs of pre-made burgers from BJs. I grilled one pack the following day and froze the others. The burgers that were not frozen came out juicy. The ones that I froze, however, always seem to be too dry. What am I doing wrong, or is there no hope for these burgers?
If the meat is lean (without much fat) it just doesn't freeze well. Fat freezes nicely, but the actual meat can get damaged by the freezing process. Which bring us to the next issue. Your freezer might not be cold enough. Especially if you're freezing them in stacks of multiple patties. You might try getting them pre-frozen, because they're probably flash frozen.
If you're going to do it your self, it would be ideal to lay them out on a cookie sheet or plate and then bagging them up once they're frozen. They'll freeze much quicker this way, preventing large ice crystals from forming; as they're the ones that damage the meat. This method goes for just about anything you're freezing.