Grape-drying (in Italian: Appassimento) is something that has been around since the beginning of wine. It's a natural way to increase the concentration of sugar in the grapes, unfortunately, at the expense of volume. That's why the famous dried-grape wines (like Amarone from Veneto and Sfursat from Lombardia) usually cost a lot. It takes about a kilo (a little more than 2 pounds) of fresh grapes to make a bottle of wine. Four to six weeks of gentle drying will reduce the weight of the grapes by about a third, meaning that same kilo of grapes will make only a half-liter of wine. But yield is only a part of the reason why these wines cost more...
These are bunches of Refosco (and some Tocai in the background) that have been picked, carefully laid in boxes, transported, and then hung on hooks and then hung in chains from the ceiling of our old farm house. Obviously this is REALLY labor intensive. All this work must be done delicately because crushing or breaking the berries could produce mold.
This year we have had fantastic weather in October, making appassimento a breeze. Often, October becomes rainy and foggy and cold, which aren't the conditions conducive to shrivel your berries:
This is a nice view of a bunch of refosco that's been hanging for about a week. You can see the individual berries are raisinating. Also you can see how much the stem has dried out. The stems are really brittle now, and taking the grapes down is a delicate process. Individual berries will fall off with almost no effort. The brittleness of the stems also presents another problem: The destemming machine breaks the stems when they are that brittle, so the bunches must be destemmed by hand.
Those "S" shaped hooks, by the way, were made hand, cut from rolls of vineyard wire, and bent into shape. All of them. Thousands of them. I must have cut and bent a thousand by myself. Andrea in the cellar, double that, at least. Even my wife made some!
Hanging the grapes is a great way to dry, because the bunches aren't laying on anything and there's airflow all around the bunch. We are lucky enough to have an ace up our sleeve as far as appassimento is concerned:
This is our sala di appassimento, or drying room, which is a temperature and humidity controlled room where we can dry grapes safely even when mother nature decides it's time to get rainy and foggy. While also quite labor intensive (all the delicacy during handling is the same), we have to maximize space, so these small flat cassettes, stacked almost to the ceiling, are the best solution. They have to be closely monitored because the grapes are on their side, and the possibility of mold is higher than when hanging.
This is some Cabernet Franc that's been drying for only about a week. Notice the berries aren't as shriveled as the Refosco. Maintaining the grapes in a single layer in these boxes that are ventilated all around is very important, as is the cleanliness of the boxes and the grapes themselves.
This year we'll probably need a little less time than normal to reach our goal of a 30% loss in weight, due to the good weather.
Last word about drying: It's not only concentration that is achieved with drying. There are substantial changes in the compounds in the grapes that give wine flavor and aroma. Much of the changes aren't well-understood, from what I've read. But the warmth and richness of dried grape wines is unique.
We use dried Refosco and Cabernet Franc in Calabrone because the grapes have a naturally high level of acidity, so while we concentrate the juice, it never gets too syrupy and cloying. We also use a small percentage of dried (Tocai) Friulano in Tocai PLUS, to give the wine its signature richness and complexity. These aren't typical practices in Friuli. But these grape varieties work so well with appassimento that they seem made for the process.