My wife brought some packages of this back from Germany. What is it and what is it used for?
It's a leavener, sometimes used in German cookie doughs, pfeffernüesse, for example.
It tends to impart a crispness to the finished pastry. Since it is principally ammonium carbonate, it is important to avoid excess usage (the smell is pungent) and to bake the product thoroughly in order to break down and drive off the ammonia.
if you don't want the Hirschhornsaltz please contact me I can use it. I love to make the old Lebkuchen recipe that my granmother used and I have ran out of Hirshhornsaltz
so if you don't want it please contact me at email@example.com,