How It's Made: Grappa

Grappa is an Italian brandy, traditionally an after-dinner drink. It's made from pumice, what's left of grapes after they've been pressed to make wine. Distilleries ferment the pumice to convert the sugars into alcohol, then distill it to transform the alcohol and other compounds into grappa. Traditional grappa is colorless. It can also be aged in wooden barrels to produce different varieties with a specific color, taste and aroma. You can't make grappa without someone first making wine, because winemaking leftovers are the sole ingredient. In Italy, the wine harvest begins in late summer or early fall, depending on the weather and region of the country. The harvested grapes go directly from the vineyard to the winery. There, the first machine pulls them off the stalks, which are later composted into fertilizer for farms and nurseries. The de-stalked grapes enter a cylindrical press. They're crushed against the walls with an airbag like device to extract the juice and pulp for making wine. What's left behind in the press, once the juice and pulp drain out, are the skins, seeds, some residual juice and pulp. This is called pumice. The winery sells it to distilleries that produce grappa. This small artisanal distillery produces premium quality grappa by using only pumice from grapes pressed that very same day. The pumice goes into temperature-controlled fermentation tanks as soon as it arrives. Large industrial distilleries operate differently, typically warehousing pumice prior to processing, sometimes for months. This delay produces high levels of potentially toxic methanol, which the distillery then has to remove using an additional procedure. The distillers monitor pH and alcohol levels to determine when the conversion of sugars to alcohol is complete. The process takes from three days to a week, depending on the variety of grape and other factors, such as the outdoor temperature. When the pumice is ready, they transfer it to wood-clad copper stills. They heat the stills with steam, bringing the pumice to the boiling point, which transforms the alcohol and other compounds into steam. This alcohol steam inside the still rises to the top and exits through a side hole. It travels through copper pipes and other equipment, ultimately to a condensation system, which cools the steam back to liquid. This liquid is grappa. As it exits distillation, the master distiller meticulously monitors the temperature and alcohol level. She discards the initial and final flows, capturing only the perfectly pure mid-flow, referred to as the heart of the grappa. Its alcohol level at this point is 70 to 77 percent. Certain varieties now go to the cellar, into small wooden barrels to age. Over time, both the grappa and the wooden barrels exchange compounds, which influence taste, aroma, and color. For example, a barrel made of cherry wood will produce different characteristics than one made of oak. The distillery's experts analyze and taste samples following distillation and throughout the aging period. Depending on the variety, this can range from just one year to more than 20 years. Whether the grappa is aged or not, prior to bottling, they filter and dilute it with demineralized water. This lowers the alcohol content from an average of 77 percent after distillation to the target level of 41 to 50 percent. They seal the bottles with stoppers made of food-safe synthetic materials rather than traditional corks. Natural cork contains certain organic compounds which can alter the flavor, aroma, and color of the grappa. They seal the stopper with shrink-wrap plastic. An unbroken seal assures the buyer that the bottle has not been previously opened. Then the bottles pass through a labeling station. The grappa is ready to be poured as an after-dinner drink or enjoyed on its own. As the Italians say, salute!