After leaving a 3/4 full bottle of vodka in the freezer for about a fortnight I found some large lumps of ice in the bottle. I was under the impression that vodka would not solidify at this temperature. How is this possible?
I think any alcoholic liquid (short of anti freeze) will solidify in a freezer after 12 or 24 hours? I have a bottle of Vodka in my cupboard that I bought in 2002 and I am sure its still good to pickle me if I drank the lot, so why are you trying to freeze vodka in the first place? If you wanted to chill it ice cold then an hour or two would have worked.
A good quality vodka will stay liquid in the freezer. Those cheaper varieties with a reduced alcohol level, (like Smirnoff, at 37.5 ABV) won't. They'll go slushy instead. Stick with a quality brand.