In past years, the differences between a liquor and a liqueur was easily separated. Vodka, gin, whisky & rum were all liquors, whereas Chartreuse, Kahlua, Benedictine, Baileys and Schnapps were all liqueurs.
Today, with many of the traditional spirits such as vodka and rum being flavoured, it has become rather difficult for many to distinguish between the two (see our affordable online flavoured selection of rums, gins and vodkas). The rule of thumb to separate the two is that liqueurs are sweet and syrupy for the most part, whereas liquors are not. In addition, liqueurs usually have a much lower alcohol content, often between 15-30% ABV and are based on distilled spirit flavoured with a variety of herbs, spices, cream, fruit and usually finished off with a sweetener typically sugar. Of course, there are exceptions to every rule.