[1] Fractional freezing is generally used to produce ultra-pure solids, or to concentrate heat-sensitive liquids.

That means almost pure water ice can be precipitated from a lean ethanol-water mixture by cooling it sufficiently.

Ice wine is the result of a similar process, but in this case, the freezing happens before the fermentation, and thus it is sugar, not alcohol, that gets concentrated.

If the contaminant is soluble in the desired solid, a multiple stage fractional freezing is required, analogous to multistage distillation.

Either method decreases the salinity of the remaining frozen water, and after multiple runs the results can be drinkable.

The danger of fractional freezing of alcoholic beverages is that it does not remove impurities, unlike (heat) distillation.

This concentration may cause side effects to the drinker, leading to intense hangovers and a condition known as "apple palsy"[4] (although this term has also simply been used to refer to intoxication,[5] especially from applejack.