Does anyone know a formula to calculate the freezing temperature of
wine given the alcohol content? Or at least a good,
hang-your-hat-on-it-and-save-the-marriage-avoiding-a-broken-carboy rule
of thumb? I've looked a little for a water/alcohol freezing phase
diagram, and haven't found anything.

It's certainly not getting cold enough during my cold-soaks this year
to worry about it, but in future years, I want to know what to be ready
for.

Rob