"Despite the pungent taste, due to being a 'new spirit', sensory analysis revealed features of a pleasant beverage, which could be further improved by aging the distillate," Armando Sampaio and colleagues write in a study due to appear in LWT - Food Science and Technology.
The team said the drink presented a "remarkable coffee aroma" and offered an interesting alternative for spent coffee ground reuse and to expand the distillates market.
Traditionally spirits are distilled from a fermented broth using grains and fruits, Sampaio et al. wrote, but during recent years interest had grown in novel distillates such as this made from "unusual raw materials that enable acquisition of different flavors, attracting new markets".
Sensible use for coffee grounds?
Agricultural residues - spent coffee grounds are currently "practically unused", the scientists assert - were potential new raw materials due to their low cost, characteristic aroma and presence of sugars that can be converted into alcohol, they add.
"Additionally, since the residual solid material obtained after the hydrothermal process is rich in sugars, it could be further reused as raw material for the production of other valuable products, which would give additional value to spent coffee grounds in a bio-refinery concept," Sampaio et al. write.
The scientists produced the distilled beverage via a three-step process, the first of which is hydrothermal extraction of the grounds.
Thereafter, they fermented this extract supplemented with sucrose to ethanol and distilled the fermeted broth.
Sampaio et al. described the first stage - for the extraction of aroma compounds from grounds, as the main difference in the production process, compared with commercial spirits.
Elegance, alcohol, finesse...
17 volatile compounds were found in the spirit, all of them in concentration values acceptable for human consumption and "able to promote pleasant characteristics to the aroma and flavor of this distillate".
Unsurprisingly, coffee, as desired, was found to be the most representative aroma after olfactory analysis by a trained panel, with 'elegance', 'alcohol' and 'finesse' featuring highly.
Tasters also reported 'pungent' and 'bitter' notes but Sampaio et al. glossed this as follows: "Such characteristics, mainly pungent, are typical of newly distilled spirits, and can be improved with aging of the distillate."
Title: 'Production, chemical characterization and sensory profile of a novel spirit elaborated from spent coffee grounds'
Authors: Sampaio, A., Dragone, G., Vilanova, M., Oliviera, J.M., Teixeira, J.A., Mussatto, S.I.
Source: LWT - Food Science and Technology, Article in Press, http://dx.doi.org/10.1016/j.lwt.2013.05.042