The base spirit of a gin refers to the distillate to which botanicals were added. It’s helpful to think about the base spirit as a vodka-like spirit that the distiller used as a starting point— a blank canvas upon which the gin was designed.
But choice of base alone doesn’t mean that you’ll be able to taste it. Depending on choices the distiller makes, such as how many times the base is distilled, or to what strength it is distilled to— there might be no character at all coming from the base spirit.
Gin is rather unique among spirit categories. While many spirits are defined by the type of distillate— for gin this is not true. Gin can have any base spirit, and as long juniper is predominant. It’s gin.
Many gins that start from a cane base are distilled in regions where sugarcane is a major crop. Think traditional rum-producing regions such as the Caribbean, South America and southeast Asia.
Cane base gins fit into two categories. Some use the cane as one would any other grain and distill it to a point of purity where there’s no residual cane flavor. But others choose to use that slightly funky cane base note as a flavor to build their gin around.