"the firewater they call 'grappa'"
is a highly potent Italian pomace brandy
. It can have up to 60% alcohol volume, and is best served ice cold. It is distilled from the leavings of grapes after winemaking; in the past, the variety of grape was not important, but now the selection is deliberately chosen. It has been produced in its most recognisable form since 1600AD, and the methods of its manufacture are protected by the European Union.
Read a nice article about drinking grappa.
Recipe for watermelon and grappa ice lollies.