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.
Rye base spirits often require a bit of barley malt to get started. Once it gets going a rye base can be one of the most distinctive and characterful bases a distiller can choose.
Many people describe Rye once distilled and aged as having a slightly sour, slightly peppery character. Neutral rye base spirit can taste even more botanical. Notes of allspice, caraway, peppermint, black pepper, or even grains of paradise aren’t unheard of. It can be complex if a distiller chooses to utilize the rye character as part of the gin. Furthermore, Rye base can also have a lovely texture and rich viscosity. The mouthfeel and character are two of the primary reasons a distiller might choose to use rye spirit as a base of their gin.