Investigating Grain-on Malt Whiskey Production Using Naked Barley

Abstract

The ability to produce malt whiskey using grain-on production methods may benefit American craft spirit producers who lack the capacity to separate grains from the wort prior to fermentation and distillation. Off-flavors thought to be derived from barley husk material have prevented distillers from producing whiskey made entirely from malt with grain-on production methods. In the present study, the impacts of using a huskless, naked barley to produce grain-on malt whiskey was investigated. New make spirit was produced at laboratory scale using malt from the covered barley variety Lightning and naked barley variety Buck. The level of esters, higher alcohols, and total polyphenols was measured in the new make spirit. Distillate made from naked barley malt (50% ABV) had a total fusel oil concentration of 2,767 mg/L while whiskey made from covered barley malt had a higher total fusel oil concentration of 3,128 mg/L. Ester levels between the two spirits were similar, with levels of ethyl acetate measuring 7.15 mg/L in the whiskey made from naked barley malt and 7.68 mg/L in the whiskey made from husked barley malt. No polyphenols were detected in either spirit. The new make spirit was also subjected to sensory analysis in the form of a triangle test and quantitative descriptive analysis. Panelists were able to detect a difference between the samples, and whiskey made from naked barley malt was perceived to have a reduction in cereal, feinty, and pungent character. Additionally, despite the naked barley being a GN producer, processing during malting reduced GN to a level associated with non-producing varieties.