The Scots gallon (Gaelic; Scottish Gaelic: galan)[1] was a unit of liquid volume measurement that was in use in Scotland from at least 1661 – and possibly as early as the 15th century – until the late 19th century. It was approximately equivalent to 13.568 litres, or very roughly three times larger than the Imperial gallon that was adopted in 1824. A Scots gallon could be subdivided into eight Jougs (or Scots pints, of 1696 mL each), or into sixteen chopins (of 848 mL each).[2]
An ale or beer barrel was 12 Scots gallons (35.81 Imperial gallons [162.816 litres]).[3]