Cask ale more plastic casks around than wooden ones. Plastic casks are increasing in popularity because they are cheaper to buy and lighter to carry. Though they don't last as long, they are also less likely to be stolen as they have no melt-down value. Beer casks come in a number of sizes, but by far the most common in the pub trade are those of 9 gallons (72 pints or roughly 41 litres) which is known as a Firkin and 18 gallons (144 pints or roughly 83 litres) known as a Kilderkin. (N.B. These are imperial gallons, equal to 1.201 US
Tub (unit) Tub (unit) Tub was a unit of capacity or of weight used in Britain and elsewhere. British laws for the sale of goods defined a tub of butter as a receptacle of a size which could contain 84 pounds of butter. 1 tub of butter or cheese = 84 pounds 1 tub = 1.5 Firkin (1 Firkin = 56 lbs) 1 tub = The "Oxford English Dictionary" has quotations illustrating other values of a "tub" as a unit: In Newfoundland, Canada, a tub of coal was defined as 100 pounds, while a tub of herrings was 16 Imperial gallons and