In the heart of London is Charles Merser & Co., the first rum blending house in the capital in over 100 years. Here, in a four-story merchant's house, rum is produced which follows the great traditions for which London was once known. A range of aged Caribbean rums is purchased, blended, married, and bottled here. Merser Double Barrel blend is created by obtaining expertly aged rum from Barbados, Jamaica, the Dominican Republic, and Panama. These different rum 'components' are then blended in London and laid to rest in casks for several months. Afterward, they are carefully bottled without the addition of color or sugars.