Definition
The quantity by which a cask, barrel, or other vessel falls short of being completely full. In commercial and customs law, ullage is significant because goods transported in casks — wine, spirits, oil, and other liquids — were taxed, assessed for duty, or sold by measure. The amount of empty space within the vessel directly affected the calculated quantity and therefore the legal obligations and commercial value attached to the shipment. A gauger measuring ullage would determine how much liquid was present, and how much was missing, whether through evaporation, leakage, spillage, or underfilling.
Common Language
Modern common usage (Wiktionary): The empty space in a wine bottle between the cork and the surface of the wine; the empty space in a cask or barrel created by incomplete filling or spillage; in industrial contexts, the empty space in a fuel tank. Also, the act of topping up a barrel with fresh wine.
Historical common usage (Webster's 1913): "The amount which a vessel, as a cask, of liquor lacks of being full; wantage; deficiency."
The common and legal meanings here are closely aligned, but the legal context adds precision: ullage in law was not merely a descriptive term for empty space but a measurement with commercial and regulatory consequences. Customs assessments, sale contracts, and carrier liability calculations all depended on a formal determination of ullage, making it a term of art in commercial gauging and excise practice rather than casual description.
Why It Matters in Research
Researchers will encounter ullage most often in historical commercial law materials, customs and excise records, and admiralty or cargo dispute contexts. Several navigational points are worth noting.
First, the term belongs to a cluster of related commercial-law words — leakage, tare, tret, caskage, gauging — that together governed how liquid goods in bulk were measured and taxed during the era when casks were the dominant shipping container. Anderson's Dictionary of Law routes the reader to LEAKAGE rather than defining ullage independently, signaling that these terms were understood as a family. A researcher who finds ullage in a primary source should consult surrounding entries on gauging, leakage allowances, and excise duty to reconstruct the full regulatory picture.
Second, ullage appears in documents and cases involving customs fraud, short measure, and carrier liability. Where a shipment arrived with more ullage than expected, questions arose: Was the shortage due to normal evaporation? Leakage? Theft? Misrepresentation at loading? The legal significance of ullage therefore shifts depending on whether the context is customs assessment, contract performance, or tort.
Third, the term is largely obsolete in modern commercial practice. Bulk liquids are now transported in standardized tanks or ISO containers measured by volume and weight, not by cask gauging. Researchers encountering ullage in contemporary sources are almost certainly working with wine industry usage (bottle fill levels) or industrial tank management, neither of which carries the historical legal freight of the customs and excise context. Do not assume modern industry usage maps onto historical legal doctrine.
Fourth, jurisdictional variations in ullage allowances — how much empty space was legally permissible before a duty reduction or penalty applied — differed between English and American customs practice and changed over time with successive excise and revenue statutes. Primary sources must be read against the specific regulatory regime in force at the time.
Historical Dictionary Support
The four source dictionaries are in close agreement on the core definition, with minor variation in emphasis. Black's (both editions) ties ullage explicitly to the act of gauging: the deficiency is discovered when a cask is gauged, not merely observed. This frames ullage as a measured and official determination, consistent with its use in customs and excise proceedings. Rapalje & Lawrence add that the deficiency arises "in consequence of the oozing of the liquor," attributing the shortage to a specific cause — leakage — rather than treating it as a neutral measurement. This is a narrower framing than Black's, which leaves the cause of the shortage open. Anderson routes the reader to LEAKAGE without independent definition, which likely reflects the practical reality that in most legal contexts where ullage appeared, leakage was the operative issue for duty or liability purposes.
None of the historical dictionaries address evaporation, theft, or underfilling as causes of ullage, though all three appear in historical case and customs records. The dictionaries also do not address ullage allowances — the legally permitted quantity of shortage — which were the operative legal standard in most customs disputes. Researchers relying solely on dictionary definitions will find the term defined but not the doctrine that made it consequential.