A Brief History of Whiskey Adulteration and the Role of Spectroscopy Combined with Chemometrics in the Detection of Modern Whiskey Fraud

Substances of health concern in home-distilled and commercial alcohols from Texas

Objective

Poor distillation practices in the production of spirits have historically resulted in many instances of adverse health outcomes including death. Concern has focused on lead and copper contamination as well as unhealthy levels of methanol and glyphosate. This study assesses home-distilled and commercially distilled alcohols from Texas for these substances of concern, highlighting their potential risks to public health.

Methods

Atomic absorption spectroscopy, gas chromatography, and enzyme-linked immunosorbent assay were employed to determine lead and copper, methanol, and glyphosate levels in 12 commercial and 36 home-distilled alcohol samples.

Results

Our findings showed that 11 % of the home-distilled alcohols exceeded the U.S. Alcohol and Tobacco Tax and Trade Bureau's copper safety limits of 0.5 mg/L for wine. Additionally, 36 % of these samples surpassed the European Commission (EC)'s lead legal threshold of 0.15 mg/L set for wine products. Results from commercial alcohols indicated that no samples exceeded the same safety limits for copper, and 33 % exceeded the same legal threshold for lead. Both commercial and home-distilled alcohols exhibited methanol concentrations remarkably below the 0.35 % limit for brandy set by the U.S. Food and Drug Administration. Only two home-distilled samples contained detectable glyphosate concentrations well below 100 μg/L, the maximum residue level in beer and wine established by the EC.

Conclusions

Our findings suggested that consumption of alcohol in Texas may pose potential health risks associated with the elevated content of lead and copper. There is a need for increased focus on alcohol as a potential source of exposure to heavy metals.

From inspection to analysis: A combined approach to identifying counterfeit whiskeys using HS-GC-FID and bottle integrity

Counterfeiting of alcoholic beverages, particularly high-value spirits such as whiskey, presents significant challenges for regulators, manufacturers, and consumers. In this study, we introduce and validate a novel application of headspace extraction (HS) followed by gas chromatography with flame ionization detection (GC-FID) for the quantitative determination of ethanol content in 42 suspected counterfeit brazilian samples of whiskeys. This method, in conjunction with visual inspection of material inconsistencies, offers a combined approach to identify potential cases of fraud. The HS-GC-FID findings revealed that only 19% of the analyzed samples had ethanol content in the limits declared on the label, emphasizing the role of ethanol content as a chemical marker for suspected beverage fraud.

Learning algorithms for identification of whisky using portable Raman spectroscopy

Reliable identification of high-value products such as whisky is vital due to rising issues of brand substitution and quality control in the industry. We have developed a novel framework that can perform whisky analysis directly from raw spectral data with no human intervention by integrating machine learning models with a portable Raman device. We demonstrate that machine learning models can achieve over 99% accuracy in brand or product identification across twenty-eight commercial samples. To demonstrate the flexibility of this approach, we utilized the same algorithms to quantify ethanol concentrations, as well as measuring methanol levels in spiked whisky samples. To demonstrate the potential use of these algorithms in a real-world environment we tested our algorithms on spectral measurements performed through the original whisky bottle. Through the bottle measurements are facilitated by a beam geometry hitherto not applied to whisky brand identification in conjunction with machine learning. Removing the need for decanting greatly enhances the practicality and commercial potential of this technique, enabling its use in detecting counterfeit or adulterated spirits and other high-value liquids. The techniques established in this paper aim to function as a rapid and non-destructive initial screening mechanism for detecting falsified and tampered spirits, complementing more comprehensive and stringent analytical methods.

The Use of a Droplet Collar Accessory Attached to a Portable near Infrared Instrument to Identify Methanol Contamination in Whisky

The aim of this study was to evaluate the ability of a droplet collar accessory attached to a portable near-infrared (NIR) instrument to characterize the artificial contamination of methanol in commercial whisky samples. Unadulterated samples (n = 12) were purchased from local bottle shops where adulterated samples were created by adding methanol (99% pure methanol) at six levels (0.5%, 1%, 2%, 3%, 4% and 5% v/v) to the commercial whisky samples (controls). Samples were analyzed using a drop collar accessory attached to a MicroNIR Onsite instrument (900-1650 nm). Partial least squares (PLS) cross-validation statistics obtained for the prediction of all levels of methanol (from 0 to 5%) addition were considered adequate when the whole adulteration range was used, coefficient of determination in cross-validation (R2cv: 0.95) and standard error in cross of validation (SECV: 0.35% v/v). The cross-validation statistics were R2cv: 0.97, SECV: 0.28% v/v after the 0.5% and 1% v/v methanol addition was removed. These results showed the ability of using a new sample presentation attachment to a portable NIR instrument to analyze the adulteration of whisky with methanol. However, the low levels of methanol adulteration (0.5 and 1%) were not well predicted using the NIR method evaluated.

Recent advances in whiskey analysis for authentication, discrimination, and quality control

In order to safeguard authentic whiskey products from fraudulent or counterfeit practices, high throughput solutions that provide robust, rapid, and reliable solutions are required. The implementation of some analytical strategies is quite challenging or costly in routine analysis. Qualitative screening of whiskey products has been explored, but due to the nonspecificity of the chemical compounds, a more quantitative confirmatory technique is required to validate the result of the whiskey analysis. Hence, combining analytical and chemometric methods has been fundamental in whiskey sample differentiation and classification. A comprehensive update on the most relevant and current analytical techniques, including spectroscopic, chromatographic, and novel technologies employed within the last 5 years in whiskey analysis for authentication, discrimination, and quality control, are presented. Furthermore, the technical challenges in employing these analytical techniques, future trends, and perspectives are emphasized.

δ13C-Ethanol as a Potential Exclusionary Criterium for the Authentication of Scotch Whiskies in Taiwan: Normal vs. 3-Parameter Lognormal Distributions of δ13C-Ethanol Found in Single Malt and Blended Scotch Whiskies

With the difference in the photosynthesis process between C3- and C4-plants, the 13C/12C stable isotope ratio of ethanol, i.e., δ13C-ethanol, can potentially be a basis for the discrimination of Scotch whiskies derived from different raw materials. This study analyzed 51 authentic single malt Scotch whiskies and 34 authentic blended Scotch whiskies by gas chromatography–combustion–isotope ratio mass spectrometry (GC-C-IRMS) and examined the resulting data by a series of fitting distribution processes. The evaluation result demonstrated that δ13C-ethanol distribution of single malt Scotch whiskies fitted both normal and 3-parameter lognormal distribution. For blended Scotch whiskies, however, the data distribution of δ13C-ethanol conformed with a 3-parameter lognormal distribution rather than a normal one. Moreover, 99.7% of the confidence intervals (CI) of δ13C-ethanol for single malt Scotch whiskies would define between −23.21‰ to −30.07‰ for 3-parameter lognormal distribution, while from −11.19‰ to −28.93‰ for blended Scotch whiskies on the basis of the statistical properties. The simulative adulterated Scotch whiskies using more than 30% C4-derived edible distilled spirits can be effectively discriminated by means of CI of δ13C-ethanol. Since the addition of rectified spirits produced from the C4 plant has been found in some cases of seized Scotch whiskies in Taiwan, establishing a CI of δ13C-ethanol would be valuable for the purpose of Scotch whisky authentication.

Examining the factors shaping consumer attitude towards the popular alcoholic beverages in Hungary

The study of consumer attitudes is particularly important for products related to tradition. Pálinka is Hungary's national beverage; the homemade distillate is primarily legally different from pálinka and it cannot be marketed. The main goal of the research is to analyse the role of the three attitude components (cognitive, affective and conative), consumer ethnocentrism and drinking motives in shaping the consumer attitude towards the Hungarian pálinka and the homemade distillate and a popular, but not Hungarian beverage, whisky.

Data were collected by questionnaires using a quota sampling method, resulting in a sample of 626 respondents.

In this paper we demonstrate the importance of the affective component using structural equation modelling, and the way consumer ethnocentrism influences the favorable consumer attitude to homemade distillate through emotions. The study has revealed the opposite effect of consumer ethnocentrism in the case of whisky, and the lack of effect in the case of pálinka.

The social alcohol drinking motivation also shapes the favorable consumer attitudes towards the homemade distillate and whisky. The consumer preference is also supported by using the Multiattribute Attitude Model and the conjoint-analysis.

The scientific value of the study lies in using different methods for understanding the factors that can shape the consumer attitude towards national beverages.

Improving the consumer attitude towards pálinka requires a comprehensive marketing strategy covering all three attitudinal components, and from a consumer ethnocentrism perspective, the positioning of pálinka as a national drink needs to be strengthened by the producers.

The study has ignored the role of brand, tradition, packaging and nostalgia. Future research can examine the role of these factors in consumer attitude towards national alcoholic beverages. By inserting the conceptual model of this study into the Theory of Planned Behaviour model, the effects of the subjective norms and perceived behavioral control can also be analysed.

Exploring the volatile profile of whiskey samples using solid-phase microextraction Arrow and comprehensive two-dimensional gas chromatography-mass spectrometry

We present a novel sample preparation method for the extraction and preconcentration of volatile organic compounds from whiskey samples prior to their determination by comprehensive two-dimensional gas chromatography (GC × GC) coupled to mass spectrometry (MS). Sample preparation of the volatile compounds, important for the organoleptic characteristics of different whiskeys and their acceptance and liking by the consumers, is based on the use of the solid-phase microextraction (SPME) Arrow. After optimization, the proposed method was compared with conventional SPME regarding the analysis of different types of whiskey (i.e., Irish whiskey, single malt Scotch whiskey and blended Scotch whiskey) and was shown to exhibit an up to a factor of six higher sensitivity and better repeatability by a factor of up to five, depending on the compound class. A total of 167 volatile organic compounds, including terpenes, alcohols, esters, carboxylic acids, ketones, were tentatively-identified using the SPME Arrow technique, while a significantly lower number of compounds (126) were determined by means of conventional SPME. SPME Arrow combined with GC × GC-MS was demonstrated to be a powerful analytical tool for the exploration of the volatile profile of complex samples, allowing to identify differences in important flavour compounds for the three different types of whiskey investigated.

What's in this drink? Classification and adulterant detection in Irish Whiskey samples using near infrared spectroscopy combined with chemometrics

BACKGROUND

Near-infrared (NIR) spectroscopy coupled with principal component analysis (PCA) and partial least squares (PLS) regression was used to analyse a series of different Irish Whiskey samples in order to define their spectral profile and to assess the capability of the NIR method to identify samples based on their origin and storage (e.g. distiller, method of maturation). The ability of NIR spectroscopy to quantify the level of potential chemical adulterants was also investigated. Samples were spiked with 0.1%, 0.5%, 1.0%, 1.5% and 2.0% v/v of each adulterant (e.g. methanol, ethyl acetate, etc.) prior to NIR analysis.

RESULTS

The results of this study demonstrated the capability of NIR spectroscopy combined with PLS regression to classify the whiskey samples and to determine the level of adulteration. Moreover, the potential of NIR coupled with chemometric analysis as a rapid, portable, and non-destructive screening tool for quality control, traceability, and food/beverage adulteration for customs and other regulatory agencies, to mitigate beverage fraud was illustrated.

CONCLUSION

Given the non-specificity of the NIR technique, these positive preliminary results indicated that this method of analysis has the potential to be applied to identify the level of adulteration in distilled spirits. The rapid nature of the technique and lack of consumables or sample preparation required allows for a far more time and cost-effective analysis per sample. © 2021 Society of Chemical Industry.

MALDI-TOF Mass Spectrometry Applications for Food Fraud Detection

Chemical analysis of food products relating to the detection of the most common frauds is a complex task due to the complexity of the matrices and the unknown nature of most processes. Moreover, frauds are becoming more and more sophisticated, making the development of reliable, rapid, cost-effective new analytical methods for food control even more pressing. Over the years, MALDI-TOF MS has demonstrated the potential to meet this need, also due to a series of undeniable intrinsic advantages including ease of use, fast data collection, and capability to obtain valuable information even from complex samples subjected to simple pre-treatment procedures. These features have been conveniently exploited in the field of food frauds in several matrices, including milk and dairy products, oils, fish and seafood, meat, fruit, vegetables, and a few other categories. The present review provides a comprehensive overview of the existing MALDI-based applications for food quality assessment and detection of adulterations.