Investigation of Appropriate Cleaning Solutions for Removal of Denatonium Benzoate from Distillery Equipment

During the COVID-19 pandemic, alcohol distilleries pivoted their production lines to manufacture hand sanitizer. Denatonium benzoate is a bittering agent and denaturant in hand sanitizer and is detectable in trace amounts. As a result, transitioning between hand sanitizer back to distilled spirits creates products with bitter flavors. Several cleaning methods were studied to determine their effectiveness in removing denatonium benzoate from materials in distillery equipment. Hydrogen peroxide and activated carbon were most effective in removing denatonium benzoate in the solution phase, with more than 40% removed compared to the original solution concentration. Strong acidic and basic cleaners were ineffective, with less than 10% of the original compound removed. When tested as cleaners on the distillery materials, hydrogen peroxide and activated carbon methods were no more effective than other rinsing (water, glycerol) or extraction (pure ethanol) cleaners for removing denatonium benzoate. Chemical compatibility, specifically with concentrated ethanol, plays a large role in the permeation of denatonium benzoate into and out of some materials. Hard materials, such as metals and rigid polymers, have good compatibility with ethanol, resulting in little swelling and denatonium benzoate penetration when soaked with sanitizer. Since they retained little denatonium benzoate, they are cleaned by simple rising. However, elastomeric materials vary greatly in their compatibility with high proof ethanol, leading to swelling or breakdown in the presence of hand sanitizer and a greater amount of denatonium benzoate leaching into the material. While ethanol effectively extracts denatonium benzoate out of the elastomers, it damages the material, requiring more frequent replacement.