What is primarily lost in the aging process of an Amontillado sherry?

The aging process of Amontillado sherry involves a significant shift in its characteristics due to the loss of the protective layer of flor yeast that develops in younger Fino sherries. When the flor dies off, the wine transitions into an oxidative aging process, which is unique to Amontillado. This loss of flor leads to the evaporation of volatile compounds and a reduction in the wine's delicate floral aromas, resulting in a deeper, nuttier, and more complex profile. In particular, the absence of flor diminishes the wine's fresh, floral notes that are characteristic of younger styles, making option B the correct choice.

Understanding this process also clarifies why the other options are less relevant. While an Amontillado can exhibit decreased sweetness over time, it typically maintains some level of residual sugar, which makes the claim of all sweetness being lost inaccurate. Similarly, the alcohol content generally remains stable during aging, and while there may be some changes in color, significant color loss is not characteristic of Amontillado; instead, it may darken. Thus, the emphasis on the floral characteristics lost due to the absence of flor accurately captures the fundamental change in Amontillado sherry during its aging process.