Definition: Three-six

Alcohol content of at least 95%. Distillation developed from the Terret grape variety. The spirits obtained in this way could withstand the passage of time and high transport costs. This spirit was called "la preuve de Hollande" (the proof of Holland), a name derived from the technique for detecting alcohol content invented by the Dutch, which gave rise to another technique used to classify alcohols into three-six, five-six, etc. according to their alcohol content.