"This is a Unicum!" - this enthusiastic reaction is attributed to Kaiser Joseph II of the Holy Roman Empire in 1790 after he tasted the herbal liqueur created by Dr Zwack for the first time. The liqueur, made from over 40 different roots and herbs, is based on a traditional recipe that is still guarded by the Zwack family today. Originally, the herbs were soaked in alcohol, enriched with sugar and used as a medicinal elixir - including being served to the Kaiser by his court physician to prevent the plague. Today, however, herbal liqueurs are no longer known for their medicinal properties.

To make Unicum, the selected herbs are macerated in alcohol for several weeks to extract the essential active ingredients. The mixture is then distilled and stored in oak barrels for six months to mature the flavour.