Soluble Complexes of Copper and Zinc in Whiskey Distillery Spent Wash

Abstract

The capacity of samples of malt whiskey distillery spent wash to complex added ionic copper was examined, and copper binding capacities of up to 3250mg litre"1 found. A correlation between the copper binding capacity and the total hexose content of spent wash was demonstrated. Gel filtration studies indicated that the copper was probably bound to an organic fraction containing both carbohydrate and ninhydrin positive material, whereas zinc appeared to be complexed by a lower molecular weight fraction containing both hexose and phenolic moieties.

Metals in alcoholic beverages: A review of sources, effects, concentrations, removal, speciation, and analysis

“…Cu and Zn form soluble complexes in the spent wash of whiskey distilleries. Cu is believed to be bound to an organic fraction containing carbohydrate and ninhydrin, whereas Zn is complexed by a lower molecular weight fraction containing hexose and phenolic moieties (Quinn et al, 1982).…”

Investigations into the Use of Copper and Other Metals as Indicators for the Authenticity of Scotch Whiskies

“…Parker and co-workers 10 used the isotope ratio 12 C/ 13 C of different volatile compounds such as acetaldehyde, ethyl acetate, n-propanol, isobutanol and amyl alcohol to differentiate between different types of blended whiskies. This is based on the fact that barley is a C3-plant, which fractionates strongly against the 13 C, while in C4-plants such as maize, enzymatic metabolism is less discriminating.…”