Gin and Vodka are highly popular drinks, both provide basis for many cocktails, so what is the difference?
The Starting Point
Gin and Vodka start out similarly. Almost anything that can be fermented can be the starting point. A grain base (barley, wheat or rye etc.) is most commonly used. Alternative include potato, sorghum and grapes. Following the fermentation stage, it is distilled and re-distilled to produce a colourless high strength spirit.
Vodka
In the case of Vodka, little more is done. Water is added to reach the required strength.The aim of most Vodka makers is to make a drink as pure and flavourless as possible. The exception being relatively rare flavoured vodkas. Vodka cocktails take on the flavour of the ingredients not of the underlying vodka. Unlike Gin, Vodka is also a popular drunk neat, best chilled.
Gin
Gin simplistically can be thought of as a flavoured vodka. Gin is made by re-distilling or compounding (mixing) with flavourings known as botanicals. (The botanicals can be added before the initial distillation). To be gin, juniper must be one. Which others are used accounts for the differing flavours and adds mystery. Premium gins typically have around 8, typically including coriander, liquorice and berries. There is no upper limit on how many botanicals can be used, here you are entering more into a marketing zone. Unlike Vodka, Gin has a distinct flavour which will influence a cocktails flavour. A simple test is to compare a Gin and Tonic with a Vodka and Tonic. Martini purists will always use Gin rather than Vodka. Read more on Gin.