Pisco punch was wildly popular at a San Francisco saloon called the Bank Exchange, whose tight-lipped owner took the recipe to his grave in 1926. There it stayed until an enterprising historian reconstructed the heavenly drink in the 1970s.
Combine pineapple with pisco in a nonreactive bowl. Cover, and refrigerate for 3 days (make sure fruit is submerged). Bring sugar and water to a boil; stir to dissolve. Let syrup cool. Stir 1/2 cup syrup and lime juice into pisco mixture. Fill 6 glasses with ice and punch. Garnish with soaked pineapple.