What does "enviado" refer to in sherry production?

In the context of sherry production, "enviado" refers to the process of seasoning barrels. This term is specifically associated with the practice of preparing and conditioning the casks that will eventually hold the wine. Seasoning barrels involves filling them with sherry or another type of wine to impart flavors and characteristics to the wood, which can enhance the quality and complexity of the sherry that will later be aged in them.

The seasoning process is crucial because the type of wood and its previous contents greatly influence the final taste and aroma of the sherry. This practice ensures that the barrels contribute positively to the aging process, allowing the sherry to develop its unique profile over time.

In contrast, the other options pertain to different stages or practices in sherry production. The fermentation process involves converting sugars into alcohol, and the aging of the wine refers to the maturation period that allows flavors to develop. Grading of the wine is related to classifying sherries based on quality and style, none of which are directly connected to the specific function of "enviado."