The role of distillation on the quality of tequila

The role of a batch rectification on the quality of tequila, a traditional Mexican beverage, was studied. It was shown that the official tequila standard composition, particularly the size of the slop cuts and the correct balance of flavour constituents, can be determined by monitoring the concentration of the regulated compounds (ethanol, methanol, higher alcohols, ethyl acetate, acetaldehyde and furfural) throughout the rectification process. It was found that these regulated compounds are produced over the same time scales when either stainless steel or copper alembics are used. When distillations were done in copper alembics, however, it was found that the copper content of the rectified product exceeded the amount permitted in the official tequila standards. Finally, we report a comparison of sensory properties of tequila distillates obtained in both copper and stainless steel alembics.