These secondary containers are the best for maturing your beer before syphoning it into your keg.

 The main advantages they offer over other containers is, they hold a full 23 litre batch and more importantly, they offer the smallest amount of air gap above the beer. This is most important during the humid months when spores of fungi suspended in the air can infect you beer.

By adding a half a teaspoon of sugar to the brew, the yeast will consume it and produce a layer of carbon dioxide which will protect you beer.