Here’s a bit of clarity to help you tell the difference between the two! The difference is very simple. Grappa is the result of the distillation of grape peel and seeds, while acquavite is the result of the distillation of the whole fermented grape. Both are fermented but the raw materials are different.
The difference lies not so much in the process, but in how they are distilled, and the materials distilled. Despite their similarities, acquavite has an elegant and fruity flavor while grappa has a more intense and structured aroma.