The state of Chihuahua is located on the northern border of Mexico and adjoins the Southern United States of America. In the Mexican United States territory, Chihuahua is likewise just beyond the states of Durango, Coahuila de Zaragoza, Sonora, and Sinaloa. The area of the state accounts for 12.6% of the total territory of Mexico, with an area of 247,200 km² (Ortega-Ochoa et al., 2008). This area is predominated with ecosystems of desert scrub and grassland, covering about 65% of the total area of the state. Furthermore, 75% of its surface is predominated by the dry semi-arid and arid climate, with precipitation ranging from 300 to 500 ml per year (Alcalá de Jesús et al., 2014; Córdova and Romo, 2014).

Under the ecosystems mentioned above, a plant called sotol, of the genus Dasylirion, grows. This species develops at extreme temperatures that can range in winter from −14 to 30°C; in summer, temperatures are ~10 to 42°C (Ortega et al., 2013). Native Mexicans used it to meet different needs, such as for food (Ladyman, 2004; Riley, 2008) and household utensils (Becerra-López et al., 2020). This plant is currently primarily used in the artisanal production of the alcoholic beverage sotol. According to regulatory bodies, in 2002, this distilled liquor acquired the designation of origin, shared between Chihuahua, Coahuila, and Durango (Mexican states).

The craft of sotol begins with gathering the Dasylirion species and cutting it in the wild for 2 days; only the stem, also known as pineapple, is used as the raw material. Next, the elaborate process continues with the cooking of the pineapple in rudimentary ovens at ground level. After that, the cooked pineapples undergo a milling process to turn them into small pieces. Then, water is added to initiate a spontaneous fermentation process. Finally, a double-distillation process permits obtaining a final product at 45% alc. vol. The distilled liquor must be graduated to 40% alc. vol. to comply with the NOM-159-SCFI-2004 specifications for its sale to the public. This alcoholic beverage is classified in the market as white, rested, and aged, with the last two being stored in dark American oak barrels from 4 months to more than 12 months.

Previous research shows that four disciplines have been addressed by sotol issues. In agriculture and ecology, pre-germination treatments on the germination of Dasylirion spp seed., statistics models to estimate the mass to be harvested from the wild population (Olivas-García et al., 2013), and the effects of substrates and chemical fertilizer on sotol seedlings have been critical topics of interest (Arce-González et al., 2007; Sierra-Tristán et al., 2008; Reyes et al., 2013). In biotechnology (chemistry), several studies have focused on the fermentation and production process to improve the organoleptic properties and regulate the quality of the product (Cárdenas-Díaz et al., 2009; Gardea et al., 2012). About health effects, it has been of interest to determine the quality of different brands of sotol, from characterizing volatile compounds and metals resulting from the distillation stage to the concentration of ethyl carbamate (De León-Rodríguez et al., 2008; Lachenmeier et al., 2009; Trujillo-Orozco et al., 2011). In an agro-industrial context, there has been an interest in diversifying the use of the Dasylirion species.

One example is to develop flour from planta seeds and manufacture probiotics and sugar substitutes from the fructans of the sotol stem (Orozco-Sifuentes et al., 2019). Sotol bagasse, a waste generated at the distillation stage, has undergone experimentation to be used in the solid-state fermentation process, although the result was negative (Flores-Maltos et al., 2014; Flores-Gallegos et al., 2019). Relying on the findings mentioned above, Figure 1 shows a Venn diagram presenting and suggesting directions for future research, with the latter highlighted in bold text. It presents the average percentage in which each of these research lines has been addressed in the texts analyzed—for example, agro-industrial and health account for 9 and 11% of scientific articles, respectively.

Regulatory bodies consider that around 500,000 L of this spirit drink is produced annually, and Chihuahua State generates 70% of total sotol production. Because sotol production is mainly artisanal, there is an increase of people who wish to diversify their monetary income through purchasing and marketing of the distillate under their trademark. The latter information can be reflected in the number of sotol producers and sotol liquor marketers registered in the Sotol Certificate Council (12 and 21, respectively). For that reason, the production of Dasylirion seedlings and regulating the quality of sotol drink add up to 80% of the research done. However, no evidence of work analyzing the carbon footprint and life cycle assessment in sotol liquor development was found so as to create proposals to mitigate its adverse effects on human health and the environment. Therefore, an assessment of greenhouse gas emissions during sotol processing would support these research lines to identify opportunities for improvement in the production process.

Regarding the latter, life cycle assessment (LCA) is a science-based tool often used to evaluate the environmental impact of alcoholic beverage processing (Leinonen et al., 2018; Baiano, 2021). The LCA methodology is ruled by international standards, such as ISO 14011:2004, ISO 14021, ISO/TR 14047, ISO/TE 14048, ISO/TR 14049, and ISO 14050, among others (Page, 2017; Patón-Romero et al., 2019; Jannah et al., 2020). In the literature, several examples of LCA application in wine, brewing, and distilled spirit industries are possible to find, as indicated below.

In wines, studies have handled a range of environmental concerns. The LCA methodology has been applied to the sustainability evaluation of wine among small-scale and large-scale wine producers, different qualities of wine, and organic and non-organic grapes wines (Iannone et al., 2016; Martins et al., 2018; Ponstein et al., 2019). Viticulture, vinification, and bottling/packaging are the main stages considered in the environmental evaluation of wine production. Frequently, it has been interesting to evaluate the environmental impact between different types of wine and varieties of grape wine (Amienyo et al., 2014; Ferrara and De Feo, 2018). Even the study of the environmental profile of the wine sector has scope in more specific production processes, such as assessing the environmental impact of an alternative process for keeping the organoleptic properties on wine (García-Alcaraz et al., 2020a) and the comparison of the techniques used for cleaning and disinfection of oak wine barrels (García-Alcaraz et al., 2020b).

Regarding the LCA of beer production, the bottling stage has the most significant impact. Diesel, as the energy source used in bottle production, is the primary driver of the global warming effect (Koroneos et al., 2005). The proposals to improve this manufacturing process include the use of thermal energy and different materials as primary packaging; for example, glass and polyethylene terephthalate are proposed (Cimini and Moresi, 2018).

The life cycle studies of distilled beverages such as gin, cognac, whisky, vodka, and mezcal have also been analyzed. The carbon footprint of both the production of a classic 700-ml gin bottle and that of the corporate has been calculated (Leivas et al., 2019). A cognac distillery (Becker et al., 2020) and one whisky distillery (Eriksson et al., 2016) have measured their carbon footprint. Vodka is another distilled beverage evaluated with LCA considering specific raw material varieties, high-volume distribution, and shipping for global market consumption (Bhattacharyya et al., 2019). About Mexican distilled liquor, the environmental impact of the artisanal process of mezcal (Maciel et al., 2020) has been evaluated.

Based on the abovementioned details, the environmental issues of wine have been mainly examined the most, followed by beer and distilled spirits. In the latter classification, Mexico has a wide variety of distilled beverages, of which the main environmental challenges of most of them are unknown. Hence, it is necessary to apply LCA in several of these because they differ in geographical conditions, the volume of production and sale, and raw material varieties. In order to gain a level of depth of analysis in the wine or brewery industry, it is considered essential to know the environmental impact of distilled beverages produced in the different regions of Mexico, such as sotol. Therefore, the main objective of this research is to identify the environmental profile of artisanal sotol production in Chihuahua, Mexico.

The framework of ISO 14040 was the guidelines for carrying out the LCA study, and all its proposed stages are defined in the following paragraphs.

The impact categories integrated in the CML-IA baseline V3.05/EU25 were fossil depletion (FD), global warming potential for a time horizon 100-year (GWP), ozone layer depletion, human toxicity potential (HTP), freshwater aquatic ecotoxicity (FAETP), marine aquatic ecotoxicity potential (MAETP), terrestrial ecotoxicity, photochemical oxidant creation potential, acidification potential (AP), and eutrophication potential. Table 3 shows the characterization of the results per functional unit in the impact categories in critical conditions. Each of the stages for sotol beverage processing significantly affects the marine ecosystem.

In line with the method to evaluate and select environmental impact categories (CML-IA baseline V3.05/EU25), MAETP is considered in the LCA study because this impact category on freshwater aquatic ecotoxicity indicates how the toxic substances to the air, water, and soil were generated on freshwater ecosystems in the Chihuahua Desert, where water is scarce and eroded soil is abundant. Though the marine ecosystem there is not in Chihuahua State, it represents a substantial portion of the harmful effects of the artisanal sotol process.

According to the study, there were no significant variations in environmental impact categories between the various types of sotol (white, rested, and aged). At the bottling stage, a minor difference between the values of the impact categories was due to the time spent in barrels by the rested and aged sotol. However, the time spent did not significantly affect the overall environmental impact of each type of sotol—for instance, MAETP has a difference of 0.38% in each value of MAETP by type of sotol. Several impact categories at the bottling stage have a difference of <5%. Human toxicity potential varies by 8.2% but does not surpass 10%.

[see the additional supporting material (S1) for further details in Madrid-Solórzano and García-Alcaraz, 2021]. S1 displays the LCA findings or environmental impacts for each type of sotol: white, rested, and aged. Within each sotol process step, the value for each impact category is arranged in decreasing order. In S1, findings show the impact categories of a 750-ml sotol bottle, whatever the type of sotol. Table 3 shows the characterization of the results per functional unit in the impact categories in critical conditions. Each of the stages for sotol beverage processing significantly affects the marine ecosystem. Based on the analysis carried out, no significant differences in environmental impact categories were presented in analyzing the data between the different types of sotol (white, rested, and aged). In this way, the results show the impact categories of a 750-ml sotol bottle, whatever the type of sotol.

Nevertheless, if critical stages are not considered, the fossil fuel resource (FD) is significantly affected by the process of cooking (33%) and distillation (35%). The latter significantly affects the AP category by 41%. Additionally, sotol harvesting mainly affects the HTP and FAETP categories by around 31%. The cooking process affects the rest of the categories in a relevant way.

Figure 3 reports the contribution rate for each of the stages of production of the distilled beverage concerning greenhouse gases. The results revealed that a 750-ml sotol bottle produces 5.92 kg CO₂ eq, based on the empirical data. The stages that contribute the most to CO₂ emissions are milling and bottling, with 51 and 27%, respectively. If critical stages are not considered, it is distillation and cooking again that influence most the environmental impact of producing a sotol bottle.

This study aimed to report the environmental evaluation of artisanal sotol production. Ten environmental indicators have been considered for sustainability performance in this research project. The evaluation used mainly empirical data gathered from the sotol production house for a functional unit of 750-ml handcrafted sotol bottle. Data collection was carried out from harvest to packaging stage.

The LCA study indicates that the milling and bottling stages are opportunities for improvements since together they contribute 4.62 kg CO₂ eq., which is equivalent to 78.04% of the total emissions. It is also noted that the transport of inputs to produce the alcoholic drink is an unfavorable condition for sotol producers in the state of Chihuahua, as glass bottles, packaging cardboard, lids, and stamps are supplied from the center of the country, resulting in high energy consumption.

In line with the results of the LCA, two suggestions are given, to be ruled by regulatory bodies to minimize system hotspots. First, it is suggested to regulate the type of machinery used in the milling stage, such that the capacity of the equipment is in line with the capacity of the liters to be produced per season, that is, that there is no unnecessary energy consumption as there is with the current process. Secondly, the weight of the generic bottles used to bottle the distilled beverage must be the lowest. These regulations will help avoid further impacts on the ecosystem.

Finding applications for sotol bagasse is intended for future research. In the literature review, there is no proposal to produce by-products from sotol bagasse. Currently, this waste ends up in an unplanned outdoor space next to the Vinata. However, there is a proposed project by the sotol production house to make souvenirs, such as cup coasters, from sotol bagasse for consumers.

In summary, this study argued that, with appropriate regulations in sotol processing, this spirit drink would be considered among those with the least negligible impact on the environment. It does not have a cultivation stage, as is the case with wine. Although according to the literature that addresses sotol production, there is an interest in generating commercial Dasylirion farming. Consequently, future research is needed to determine the carbon footprint for this type of farming.

The data analyzed in this study is subject to the following licenses/restrictions: Information comes from a private company. Requests to access these datasets should be directed to jorge.garcia@uacj.mx.

JM-S contributed to conceptualization, data curation, investigation, and writing (original draft). JG-A contributed to writing (review and editing). JF contributed to visualization and supervision. EC contributed to software, formal analysis, and data curation. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.