Is this fixable?
My spouse is very social. She has a heart of gold and will do anything for anyone. However when she gets to drinking heavily, she get rude and mean. It isn't all the time but some I don't appreciate the negativity.
Alcohol lowers our inhibitions, sometimes with disastrous consequences, and it causes ongoing issues if we become reliant on it. It tells you who your wife really is despite her heart of gold. You need to be aware that even if she drinks heavily even occasionally, and it affects her personality, then it's an issue which could go on to become a major problem. She needs to limit herself as to how much she drinks, what she drinks and how often. You state that she is very social but it may well be that she can't be social without alcohol being involved, and if that's correct, then that's the real issue here, regardless of how much she drinks.
Sure, you can discuss her unacceptable behavior with her but it's her decision to act on it. You need to set boundaries and may even have to give her an ultimatum to get her to sit up and take notice, but she has to be the one to realize this and change her drinking habits. The effort is all hers and in the meantime, you and other people close to her will suffer from her actions when she's drinking heavily.
There's only so much you can forgive and forget but alcohol abuse takes no prisoners and doesn't discriminate with who it affects. Your challenge is to get your wife to realize this now before it becomes a major issue.