everyday chemistry - How can I separate the vinegar from a 5% white vinegar to make a more concentrated solution.

I was under the impression that if I put a semi full bottle of vinegar in the freezer the water would freeze but the vinegar would not until a lower temp. Therefore I could remove the bottle after the water freezes and pour off the vinegar. Apparently the water and vinegar doesn't separate nicely before freezing so this didn't work so well.

I've seen boiling suggested but I'm afraid I'll lose some of the vinegar in the process.

What is the simplest way to concentrate the vinegar at home?