Louching is a technique used to prepare absinthe for consumption. While people do not have to louche absinthe to drink it, many do, because louching gives absinthe the distinctive milky glow which many people associate with this drink. Most establishments which serve absinthe also provide the tools for louching, or perform the louching themselves before serving the drink.
When absinthe is louched, cold water is added to the beverage, triggering a reaction which causes the drink to cloud and turn milky. When louching is performed with a practiced hand, billows of milky color ripple through the glass, creating a luminescent glow which is quite distinctive. The ratio of water to absinthe varies, depending on the absinthe and personal taste, although a 1:3 ratio of absinthe to water is very common.
In some cases, louching is performed by dripping cold water through a sugar cube positioned on an absinthe spoon at the top of the glass. This form of louching sweetens the absinthe as well as clouding it, masking the bitter flavor of natural absinthe. The sugar cube also acts as a filter, slowing the flow rate of the water to ensure that it drips slowly into the glass, as dumping water into a glass of absinthe does not achieve the desired aesthetic effect.
Other consumers prefer to skip the sugar cube, simply dripping water with a steady hand directly into the glass to generate the desired cloudy absinthe. Water can also be drizzled through a spoon to control the rate of flow. This type of louching is best recommended for naturally sweet absinthes or consumers who are familiar with the bitter flavor of unsweetened absinthe. It does have the benefit of allowing the natural flavors in the absinthe to come through, resulting in a more complex mouthfeel.
Different types of absinthe louche in various ways. The amount of louching is dependent on the amount of anise in the absinthe. Higher anise levels will generate a cloudier liquid, with some absinthes turning almost white in response to the cold water, while lower levels will result in less cloudiness. Other drinks which traditionally contain anise, such as ouzo, are also sometimes louched before service. Louching provides a useful visual indicator that the drink has been diluted, making it less potent than it would be in straight form. In the case of absinthe, dilution is desired, as this beverage is extremely strong.
