Crushed grapes used for wine manufacturing are commonly referred to as must. Must is essentially the freshly crushed fruit juice, typically grape juice, that contains not only the liquid but also the skins, seeds, and stems of the fruit. This combination of components is crucial in the winemaking process as it contributes to the flavors, aromas, and overall structure of the resulting wine.
When grapes are harvested and brought to the winery, they undergo a process known as crushing, where they are gently broken open to release their juice. This step is essential in extracting the flavors and sugars from the grapes, which will ultimately be fermented into wine. The crushed grapes, along with their skin, seeds, and stems, are then transferred to a vessel for fermentation, such as a tank or barrel.
The inclusion of the skins, seeds, and stems in the must is significant as they contain various compounds that greatly influence the characteristics of the wine. The skins, for instance, contribute color, tannins, and certain aromatic compounds. Tannins are natural compounds found in grape skins that provide structure and astringency to the wine. They can also contribute to the aging potential of the wine. The seeds, on the other hand, contain tannins as well as oils and other compounds that can affect the flavor profile of the wine.
Having the stems in the must can also impact the winemaking process. In some cases, winemakers may choose to remove the stems before fermentation, a process known as destemming, as they can impart a bitter taste to the wine. However, leaving some or all of the stems in the must, a technique called whole-cluster fermentation, can add complexity and additional tannins to the wine.
While must is most commonly associated with grape juice, it can also be used to refer to the crushed juice of other fruits used in winemaking, such as apples or pears. In these cases, the must will contain the juice along with the skin and pulp of the fruit, providing similar contributions to the final product.
In my experience as a sommelier and brewer, working with must is a fundamental part of the winemaking process. The careful handling of the grapes during crushing and the management of the resulting must are crucial in preserving the quality and integrity of the fruit. The selection of the desired components to include in the must, such as whether to destem or use whole clusters, is a decision that winemakers make based on their desired style and the characteristics they want to achieve in the final wine.
Must serves as the foundation for winemaking, providing the raw materials and essential components necessary for fermentation and the development of flavors and aromas. Its inclusion of the skins, seeds, and stems adds complexity and structure to the resulting wine, making it a key element in the production of quality wines.