I'd guess that they burn it off. It's fairly easy, though you can't get 100% of the alcohol out this way at home. You can make a vinegar out of liquor this way

I'd guess that they burn it off. It's fairly easy, though you can't get 100% of the alcohol out this way at home. You can make a vinegar out of liquor this way by burning the alcohol off of a handle of liquor, pouring a fifth back in, and adding a vinegar mother with some live vinegar to kick it off before waiting 4-6 weeks.