This question was put on hold as off-topic because it was a nutrition only question (the same reason that all questions that are to the effect of "should I do X diet plan?") However, since it's specifically about storing protein powder in the freezer and not asking about nutritional benefits per se, I think that this question was improperly closed. Almost every weightlifter uses protein powder. This question seems like it'd be a good addition to the knowledge base, even if the answer is simple.
Since I'm new to the SE, I assume I'm missing something. Where is the flaw in my thought process?