
Pisco is a clear grape brandy from Peru and Chile, distilled from fermented grape must. The Peruvian style is bottled unaged and clear, tasting purely of the grape, with no oak behind it; Chilean pisco may instead be oak-rested.
It is an unaged grape spirit, and the family it belongs to is small: anything clear and distilled from wine sits close, anything aged does not. The aroma comes from the grape varieties, so no substitute reproduces it. Expect the shape of the drink to survive and its perfume to change.
Distilled from pomace — pressed skins and pips — rather than from the must, so it comes out sharper and grassier. In a sour it reads rougher and the grape note goes rustic.
Aged in oak, amber and rounded, where the Peruvian style is unaged and all about fresh grape; swapping it in darkens the drink and buries the varietal aroma the recipe was built on.
Aromatic piscos such as Italia, Torontel and Moscatel hold their character the way an aromatic grappa does, which is to say imperfectly, and lose it to the air above the spirit. Quebranta and the other non-aromatic grapes are far steadier. Either way, dark and upright, and decant when the bottle empties.