How is the ethyl carbamate concentration reduced?

It has been recognized that the ethyl carbamate concentration of fruit distillates can be reduced by adding a catalyst. For this purpose, the copper surface of the distillation device is greatly increased. When the vapors come into contact with copper, hydrocyanic acid, a precursor of ethyl carbamate, reacts to form heavy copper compounds that cannot be transferred to the distillate.

The catalysts available today are installed in the distillation device between the dephlegmator and the cooler, either vertically on the column or laterally adjacent or horizontal. The copper catalysts can consist of packings, rings or lamellas. Regardless of the design, the catalyst can be switched off during distillation. Regular cleaning is important for the effectiveness of the catalyst, as the hydrocyanic acid and other mash ingredients react with the copper and form deposits. Fats and waxes also deposit on the surface of the catalyst and form water-repellent coatings. The result is that the prussic acid can no longer react with the copper and the catalyst no longer has any effect. For this reason, the catalyst should be rinsed with hot water between firings and carefully cleaned regularly with cleaning lyes and citric acid so that the copper surface becomes bright again.