Empty portion of a bottle
Else clues• Amount lacking to make a full cask
• Amount needed to make a full cask
• Grain lost through spilling
• Liquid amount lost in storage
• Short-of-fullness amount
• Unevaporated amount in a cask
• Unfilled part of a wine cask
• Unfilled part of a wine container
• The amount that a container (as a wine bottle or tank) lacks of being full