Having spent most of my life in the wine business, I thought I was immune from novice mistakes. However, the other day I thought I did not have enough chilled white wine for dinner so I decided to put a sauvignon blanc in the freezer for a quick chill. Needless to say I forgot about it. The next day I realized my mistake and now it give me the chance to describe what happens. I most cases, freezing wine will not incur any problems. The wine will reconstitute itself after thawing and the taste will most likely be unaffected. However the danger lies in the wine expanding upon freezing causing a pushed out cork or a split bottle if the glass is week. Fortunately there was enough eulage ( space between the wine and the cap) to absorb the expansion.
The other characteristic of frozen wine is the appearance of tartrate crystals. Many times people would tell me “there’s glass in my wine”. Actually it’s tartaric acid (cream of tartar) that has precipitated out. Totally harmless. Most wines undergo a cold fermentation to pecipitate them out before bottling but freezing carries the process to another level.
Gulf Coast Wine Journal 