While the exact approach differs from producer to producer, the fundamental process to making Gin consists of three steps. Its base is a clear, distilled grain spirit (or occasionally a molasses based spirit) that has no flavor or color. The flavor comes from the various botanicals that are added, as well as the unique distillation process applied by the producer. The three step process is as follows:
Step 1: Distill the base spirit.
The grain alcohol is distilled in a column still to a high proof, flavorless spirit.
Step 2: Distill the spirit again with the botanicals.
The second stage is what differentiates a high quality gin from a lower quality compound gin. The lower quality versions are typically produced by soaking the botanicals and juniper berries in the base spirit and distilling the mixture a second time. The higher quality versions are flavored in a more unique manner. The alcohol vapor is passed through a chamber that holds the botanicals and juniper berries. This vapor will extract the essential oils and aromatics from the botanicals as it passes through the chamber and on to the condenser.
Note that a small still or use of small batches results in a higher quality Gin and is best able to capture the essences of the botanicals. This allows the Gin to maintain the balance of ingredients needed to create depth and character.
Step 3: Add water and bottle
Pure water is added to bring the strength down to the legal requirement before the final product is bottled. Gin is ready to be bottled straight from the still. Unlike Whisky, it does not need a period of time for maturation