The distinctive point
US beer barrel (31 US gallons): a rule rather than an average
The matrix treats this value as exact because its recorded basis is thirty-one-us-liquid-gallons. The interesting distinction is epistemic: a defined standard can be converted without an uncertainty band, while reconstructed ancient standards cannot inherit that certainty.
Basis: thirty-one-us-liquid-gallons. Check the record source.
No same-system neighbour is modelled; the source and period carry the context.
What this unit was
US beer barrel (31 US gallons) is modelled here as a liquid standard of the US brewing measure tradition, associated with United States during Current federal brewing measure. The converter represents one US bbl as 117.34777 L; its basis is thirty-one-us-liquid-gallons. This is a defined or exact matrix anchor.
Within that setting, the unit belonged to a working system for storage, rations, trade, and the circulation of drink or other commodities. It should be read with its period, locality, and evidential basis attached, not as a universal value shared by every culture using a similar name. A vessel name is not automatically the capacity of every surviving vessel.
Evidence of use and sources
The working value is traceable to US Alcohol and Tobacco Tax and Trade Bureau. Its record is classified as exact confidence and uses the stated basis rather than an assumed culture-wide constant.
The local library supplies contextual quotations; the linked record source remains authoritative for the modern definition.
“the ten millionth of the meridian quadrant ... be called a metre”
Standard measures of United States, Great Britain, and France, PDF p. 16. metric origin proposal
“A standard is a physical representation of a unit.”
A dictionary of weights and measures for the British Isles, PDF p. 31. standard versus unit
“the omission of necessary facts”
Standard measures of United States, Great Britain, and France, PDF p. 10. conditions required for comparison
Working definition
US beer barrel (31 US gallons) is represented as a US brewing measure standard associated with United States during Current federal brewing measure.
The converter uses 117.3477653 L per unit.
How to use it
Basis: thirty-one-us-liquid-gallons; confidence: exact. A shared historical name does not make this value portable to another period or polity.
Open this unit in the Liquid converter · Return to all units