Flavoured vodkas have only recently become fashionable, but in fact, the earliest vodkas were always flavoured, although this was entirely due to necessity.
When commercial distillation got under way, during the 14th and 15th centuries, the original technology was obviously crude, and distillers lacked the ability to purify the spirit, hence the need for the addition of herbs and spices to mask the unpleasant impurities. Nowadays, a vast array of flavours are used in vodka production, including horseradish, toffee, espresso and even marmalade.
With modern palates much sweeter than in previous years, a range of vodka based liqueurs have appeared, with sweet and sticky flavours very much the fashion. Toffee vodka is very much a favourite, with brands such as Thunder Toffee and Toffoc known around the world, especially as part of Après-ski culture.