Gin is a pure spirit combined with natural ingredients. The finest gin has a grain base, although in some cases molasses is used. A double distillation process is employed, with a secret blend of herbs and spices (botanicals) being added to the final distillation. A number of herbs and spices are utilized, the most important of which is the juniper berry, which gives gin its zest. Other ingredients may include coriander seeds, cassia bark, licorice, orange and lemon rind, ginger, cinnamon and orris root.

The early gin pioneers established their distilleries in north London to take advantage of the pure water that lay below the city. Their pure, unsweetened gin became known as London Dry Gin. In addition to mixing it with tonic or serving it as a dry martini, gin can also be combined with fruit juices and bitter lemon.