The legal drinking age in Austria is 16 (18 for hard liquor).
There are however some notable exceptions:
From the age of 14 minors can consume alcohol that is provided by their parents.
In Vienna, Lower Austria and Burgenland the legal age for all types of alchol is 16. (Including liquor)

On-premise consumption is subject to provincial regulation.
In general, the minimum drinking age is 16 however:

in one province the minimum drinking age is 16 for spirits and 15 for wine and beer.

Some provinces prohibit consumption of spirits for those under 18.