Structurability: A Collective Measure of the Structural Differences in Vodkas

Abstract

Although vodka is a reasonably pure mixture of alcohol and water, beverage drinks typically show differences in appeal among brands. The question immediately arises as to the molecular basis, if any, of vodka taste perception. This study shows that commercial vodkas differ measurably from ethanol-water solutions. Specifically, differences in hydrogen-bonding strength among vodkas are observed by (1)H NMR, FT-IR, and Raman spectroscopy. Component analysis of the FT-IR and Raman data reveals a water-rich hydrate of composition E x (5.3 +/- 0.1)H(2)O prevalent in both vodka and water-ethanol solutions. This composition is close to that of a clathrate-hydrate observed at low temperature, implying a cage-like morphology. A structurability parameter (SP) is defined by the concentration of the E x (5.3 +/- 0.1)H(2)O hydrate compared to pure ethanol-water at the same alcohol content. SP thus measures the deviation of vodka from "clean" ethanol-water solutions. SP quantifies the effect of a variety of trace compounds present in vodka. It is argued that the hydrate structure E x (5.3 +/- 0.1)H(2)O and its content are related to the perception of vodka.

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“…However, each brand has its own distinctive taste and features on the molecular level. Research conducted by Hu et al (2010) [8] confirm that these differences are significant both during the stage of creating WAM, and in the final product -the commercial vodka. The major differences are associated with hydrogen bonds, in particular their strength, as confirmed by various research methods such as (Hu et al, 2010) [8] attribute this value with the perception of organoleptic characteristics of vodka.…”

“…But every brand has some observable differences on the molecular level and as to the taste perception. Studies conducted by Hu N. and others in the work (Hu et al, 2010) [19] prove that these differences are significant either on the stage of AAM making or in the final product -commercial vodka. The main differences are connected with hydrogen bonds (with their strength) that is proved by different research methods, for example by In the work by Nose A. and others (Nose et al, 2005) [20] the influence of admixtures such as salts, acids and phenols on the strengthening of hydrogen bonds in AAM and in finished products as well, in this case sake, is studied.…”

“…The spectra of some samples are represented by the appearance of a second broadened OH signal of ethanol at a level of δ OH =5,5 ppm. The presence in the samples of a single signal of OH ethanol (Hu et al, 2010) [8] is attributed to the weak hydrogen bonds of ethanol.…”

“…In the opinion Hu et al (2010) [8] vodka is a fairly simple physicochemical system: a mixture of alcohol and water. However, each brand has its own distinctive taste and features on the molecular level.…”

“…In their paper, the authors (Hu et al, 2010) [8] introduced the concept of «structurability» -defined as the ability to maintain structure -a parameter that determines the ability of vodka (alcohol) to streamline its structure.…”