During the early years of the 19th century Carreras began trading in London at a time when cigars were increasing in popularity and Don José became a pioneer in his field. However, although the business prospered it did not become a major concern until his son, Don José Joaquin, began to specialise in the blending of tobaccos and snuff. By 1852 Don José Joaquin Carreras had established himself near Leicester Square at 61 Prince's Street W1, and in 1853 was granted a warrant as the sole supplier of cigars and tobacco to the Spanish Legation in London. His fame as a tobacco blender soon spread, and he produced blends to suit the individual tastes of the highest members of society, with customers visiting his showrooms to select their own tobaccos. One of Don José's most famous customers was the third Earl of Craven. A special blend, to become known as Craven Mixture, was created specially for him and this blend has since spread in popularity throughout the world. Some of Don José's tobacco brands became world famous, including Guards' Mixture and Hankey's Mixture. Over one thousand brands of cigar could be bought from Carreras, together with snuffs, cigarettes, pipes and all the usual requisites of the trade.