The word "ullage" is pronounced as /ˈʌlɪdʒ/. It refers to the empty space left in a container, such as a bottle or barrel, after liquid has been removed. The spelling of "ullage" may seem unusual, but it comes from the French word "ouillage" which means "filling up." The "o" was changed to "u" over time, and the "i" was replaced with an "l" to better reflect the pronunciation of the word. Despite its unusual spelling, "ullage" is a useful term to know for those working in industries that involve containers and liquids.
Ullage refers to the empty space or the amount of empty space within a container, such as a bottle, barrel, tank, or cask, that is left unfilled or unoccupied by its contents. It is essentially the void or gap between the top of the liquid and the top of the container. Ullage commonly occurs due to evaporation, leakage, shrinkage, or other factors affecting the volume of the container's contents.
The term "ullage" is particularly used in industries where precise measurement and monitoring of liquids is crucial, such as in winemaking, distilling, brewing, or oil and gas production. It serves as a measurement of the volume, depth, or extent of unfilled space, allowing for accurate inventory management, quality control, and estimation of product loss or evaporation rates.
In addition to its application in liquid containers, "ullage" can also be used in a figurative sense to indicate the wasted or unused space within a room, storage area, or a structure. It can also refer to the deterioration or degradation of fluid properties due to exposure to air or inadequate sealing.
Overall, "ullage" plays an important role in ensuring the accurate measurement, preservation, and management of liquid contents, while also providing insights into the condition and performance of the container or its contents.
Among gaugers, what a cask wants of being full; properly, the quantity required to fill it up.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "ullage" originated from the Anglo-French term "oulage" or "ollage", which ultimately comes from the Old French word "oule" meaning "container" or "vessel". It entered the English language in the 15th century and specifically referred to the amount of liquid or air space remaining in a partially filled container, particularly in the context of measuring the level of wine in a barrel. Over time, the term "ullage" has been extended to refer to any vacant space in a container or vessel.