Pisco is the national spirit of both Peru and Chile and in both countries the iconic cocktail is the pisco sour, which, understandably in such hot climes...
you should recheck your source. Pisco sour is not blended with ice, its shaken and served without ice. I really like this page and the info its usually on point but I live in Peru and pisco sour its not how you put it. GET IT RIGHT!