linguistic:paraphrasing, linguistic:translation
Ageing and blending

Many countries require rum to be aged for at least one year. This ageing is commonly performed in used bourbon casks, but may also be performed in other types of wooden casks or stainless-steel tanks. The ageing process determines the colour of the rum. When aged in oak casks, it becomes dark, whereas rum aged in stainless steel tanks remains virtually colourless.

Due to the tropical climate common to most rum-producing areas, rum matures at a much faster rate than is typical for whisky or brandy (i.e. achieving a similar level of maturity takes considerably less time). An indication of this higher rate is the angels' share, or the amount of product lost to evaporation. While products aged in France or Scotland see about a 2% loss each year, tropical rum producers may see as much as 10%.

After ageing, rum is normally blended to ensure a consistent flavour, the final step in the rum-making process. During blending, light rums may be filtered to remove any colour gained during ageing. For dark rums, caramel may be added for colour.

There have been attempts to match the molecular composition of aged rum in significantly shorter time spans with artificial ageing using heat and light.