A Calquat keg is created by using a knife on a calquat fruit. Calquat fruit can be player grown using the Farming skill, at level 72. For players who are not able or interested in growing their own kegs, they can buy it from another player.
Calquat kegs are used in brewing, to collect complete batches of ale. Each keg can carry the equivalent of 4 beer glasses worth of ale or cider (4 doses). Players can fill up to 2 Calquat kegs from one batch of ale, by using them on the barrel of completed ale (attached to fermenting vat). However, ale already in beer glasses cannot be placed into a calquat keg.