“Because he plainly perceives that his piquette stands in need of being enlivened by a mixture of good wine.”

Further down the list in quality came other more or less famous wines, such as the wine of Sorrentum which Tiberius could not bear, finding it an insipid taste and disgusting.' The extravagant Caligula gave it the name of 'piquette'. (This is an official French word, in the Code du Vin, and means a drink made by adding water to the marc of grapes and fermenting it. Such a wine in France can only be used for family consumption and
must not be transported from one place to another with a view to sale.)

Who wants to tell us what "marc" is?