Solera

A solera system is an ageing process that uses fractional blending within a sequential series of casks. The result is that the final product bottled from the solera will contain a mixture of liquid within a range of various ages, with the overall average age increasing as the process continues. This is achieved by bottling from the what is called the solera, the bottom cask in the arrangement (solera means "on the ground" in Spanish), which is replenished from the cask (known as criaderas) one step up on the chain and so on, with no cask every being fully emptied. The practice was devised by sherry makers in Spain, but variations are used across the world for other wines, as well as other products such as vinegars, brandy, beer and of course, rum.

Due to the historical links of solera ageing to the Iberian peninsula, the practice of solera maturation for rum is mostly, although not strictly confined to the Spanish speaking countries of the Caribbean and South America. The first brand to advertise the use of a solera system was Santa Teresa in Venezuela in the 1990s, followed shortly by Guatemala's Ron Zacapa.

It should be noted that solera systems at rum distilleries have some notable differences to those traditionally used by sherry bodegas. While a sherry solera will use the same arrangement of casks for many decades, rum distillers will often introduce new casks of varying types at each refilling stage. The use of solera ageing in rum is also not one without some controversy, in part due to the adaptations to the solera practice itself, but particularly around the stated age of the rums bottled from it. While efforts have been made in recent years to improve transparency in this area, it should be noted that numbers or age statements on rums of this type may not reflect the youngest spirit in the blend, as is customary of blends produced from traditional cask maturation.