vintage assessment is important enough to have an immediate effect on price but is also notoriously difficult because quality and character can vary so much between producers and properties. A vintage is often assessed at the most difficult stage in its life, its infancy, for reasons of commerce and curiosity. Wine merchants and wine writers habitually taste wines from the most recent vintage in a wine region important for investment when they are just a few months old and are still in cask (see en primeur). Quite apart from the fact that the wines are at this stage still being made (see élevage), samples may give a misleading impression because they have been specially chosen and groomed to show particularly well at this early stage, or too long has elapsed since they were drawn from cask (oxidation is a common problem), or, if they are tasted directly from cask, because they are undergoing a distorting treatment such as fining
. Furthermore, this sort of vintage assessment may be before the assemblage process and provides only a snapshot of embryonic wine from a small proportion of the total number of barrels produced.