Demijohn

A carboy, demijohn, or jimmyjohn is a rigid container with a typical capacity of 20 to 60 litres (5 to 16 US gal). Carboys are primarily used for transporting liquids, often water or chemicals.

They are also used for in-home fermentation of beverages, often beer or wine.

The word carboy is from the Persian qarābah (), from Arabic qarrāba, "big jug".

"Demijohn" is an old word that formerly referred to any glass vessel with a large body and small neck, enclosed in wickerwork. The word may derive from the name of a Persian town, Damghan, but this is not supported by any historical evidence. According to The Oxford English Dictionary the word comes from the French dame-jeanne, literally "Lady Jane", as a popular appellation. This is in accordance with the historical evidence at present known, since the word occurred initially in France in the 17th century, and no earlier trace of it has been found elsewhere.

Carboys come in various volumes ranging from 4 to 25 L (1.1 to 6.6 US gal). The term carboy itself usually refers to a 19 L (5.0 US gal) carboy, unless otherwise noted. A 4.5 L (1.2 US gal) carboy is usually called a jug. A 57 L (15 US gal) carboy is usually called a demijohn (in the Philippines, dama juana.)

In Britain, "demijohn" refers to a 4.5 litre (imperial gallon) glass brewing vessel.

Containers of this type in the United States have no specific volume and are called "jimmyjohns".

In brewing, a carboy or demijohn is a glass or plastic vessel used in fermenting beverages such as wine, mead, cider, perry, and beer. Usually it is fitted with a rubber stopper and a fermentation lock to prevent bacteria and oxygen from entering during the fermentation process.

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