Back in September, we highlighted one of our favorite drinks of the moment: the pisco sour at Yerba Buena. The classic frothy beverage combines pisco (Peru’s national grape brandy) with lime juice, egg white and bitters. The brand used at Yerba Buena is called Macchu Pisco, and it’s been popping up on cocktail menus throughout the city, along with its two sister labels—La Diablada and Ñusta—from the same family-owned company. To get a better sense of just how bartenders are using the spirit right now, TONY tagged along with Macchu Pisco owners (and sisters) Lizzie and Melanie Asher on a high-octane bar crawl covering Death & Company, PDT, The Crosby Bar, Summit Bar, Yerba Buena, wd~50 and Apothéke. Take a look at the slide show for highlights of the tour, and read after the jump to sharpen your pisco knowledge.

A few fun facts:

• Pisco comes in three main categories: puro (pure), acholado (blended) and mosto verde (green must).
• Puro piscos are made from one type of grape, and are themselves divided into aromatic and nonaromatic categories, depending on the varietal used.
• Acholados are blends of the distillates of various grapes, such as the delicate and floral La Diablada, produced by the Asher sisters.
• Mosto verde is distilled after it is only halfway fermented, resulting in a much diminished yield. It is best sipped alone.
• The most traditional grape for pisco is called quebranta, meaning “broken.” It was brought by Spanish explorers to South America from the Canary Islands, and was essentially “broken in” to survive the Peruvian climate, hence the name. Macchu Pisco is 100 percent quebranta, and it makes a less fruity and floral spirit. Other pisco grapes can be much more aromatic.
• Pisco is different from Italian grappa in that grappa is distilled from pomace (the solid remnants like skin and seed after wine has been pressed), while pisco is distilled from freshly fermented grape juice with no associated wine production.