Tej is a traditional Ethiopian honey wine, akin to mead, produced through the spontaneous fermentation of honey, water, and the leaves and stems of the gesho plant (Rhamnus prinoides), which imparts a distinctive bitter flavor and aids in the fermentation process.[1] This indigenous beverage typically achieves an alcohol by volume (ABV) content ranging from 7% to 11%, though variations can reach up to 12% depending on fermentation duration and regional practices.[1] Served in a distinctive berele, a traditional flask-shaped glass vessel,[2] Tej is characterized by its golden-yellow hue, sweet yet slightly bitter taste, and turbid appearance, making it a staple in Ethiopian social and ceremonial contexts.[3]As one of Ethiopia's most widely consumed traditionally fermented alcoholic beverages, Tej holds profound cultural, social, and economic importance, often featured in weddings, religious holidays, and communal gatherings where it symbolizes hospitality and celebration.[4] Its production remains largely artisanal and household-based, involving a multi-stage process: honey and water are first mixed (typically in a 1:3 ratio), allowed to undergo primary fermentation for 3–4 days, then filtered and combined with ground gesho for secondary fermentation lasting 8–21 days under anaerobic conditions.[3] This spontaneous fermentation relies on naturally occurring yeasts (such as Saccharomyces species) and lactic acid bacteria, contributing to Tej's probiotic potential and nutritional profile, which includes antioxidants, vitamins, and minerals derived from the honey and gesho.[3][4]Tej's enduring popularity stems from its integration into Ethiopian daily life and traditions, with regional variations in Amhara and other areas incorporating additional elements like wheat malts or specific honey types to enhance flavor and yield.[1] Despite challenges from inconsistent quality due to uncontrolled fermentation, ongoing research focuses on starter cultures to standardize production while preserving its authentic character.[3] Economically, it supports local beekeeping and herbalcultivation, underscoring its role in sustainable practices within Ethiopian communities.[1]
Etymology and Terminology
Origin of the Name
The term "Tej" derives from the Amharic word t'ej (ጠጅ), which specifically denotes "honey wine" but more generally signifies "wine" in the context of Ethiopia's indigenous fermented beverages. In Amharic, to refer to grape-based wine, the compound phrase wayn t'ej is employed, where wayn means "grape," highlighting how t'ej encompasses honey-derived drinks as the traditional default.[5]Phonetic and orthographic variations of the name, such as "Tej," "T'ej," or "t'äj," stem from differing conventions in romanizing the glottal stop and ejective consonant in the Amharic script, which can lead to inconsistencies in English transliterations. These variations do not alter the word's core meaning but reflect the challenges of adapting Ethio-Semitic phonology to Latin script.
Related Terms and Regional Variations
In Amharic, the primary language of Ethiopia, tej serves as the general term for wine, with the honey-based variety simply referred to as tej and grape wine distinguished as wayn t'ej (where wayn denotes grape).[6] This linguistic convention highlights the cultural primacy of the honey-fermented beverage over imported grape varieties.[7]Regional variations reflect Ethiopia's and Eritrea's linguistic diversity. In Tigrinya, spoken in northern Ethiopia and Eritrea, the drink is known as mes, a term derived from ancient Ge'ez usage during the beverage's early origins in the region.[7] Among Oromo communities in southern and central Ethiopia, it is called daadhii, emphasizing local adaptations within Cushitic-speaking areas.[7] In some southern Ethiopian locales, such as among the Gurage, a variant is termed boke.[7]Post-20th century interactions with Western cultures have introduced English descriptors like "Ethiopian mead," facilitating global recognition while preserving indigenous nomenclature in local contexts.[7] These terms underscore minor dialectical differences without altering the beverage's core identity across Ethio-Eritrean traditions.
History
Ancient Origins
Tej's ancient origins trace back to the Horn of Africa during the rise of the Aksumite Empire, approximately 2,000 years ago, where the fermentation of honey into an alcoholic beverage emerged as a key cultural practice. Archaeological excavations at Aksum and nearby sites have uncovered pottery and amphorae indicative of beverage production and trade, including vessels that likely held fermented liquids, suggesting the early development of honey-based drinks using local resources like honey and indigenous plants. These findings align with the empire's advanced agrarian economy, which relied on beekeeping, establishing Tej as a precursor to later traditions.Historical inscriptions from the Aksumite period provide direct textual evidence for the consumption of such drinks, including ration records mentioning "mes" (hydromel or honey wine). For instance, 3rd-century CE stone inscriptions describe the serving of "mes" in ceremonial contexts using specialized vessels like the gabata, highlighting its role in social and ritual life. King Ezana's 4th-century writings further reference honey wine, underscoring its integration into elite and royal practices within the empire, which spanned northern Ethiopia and Eritrea from roughly 100 BCE to 940 CE.[8]The development of Tej was influenced by longstanding honey fermentation traditions across Africa and the Middle East, dating to around 1000 BCE. In ancient Egypt, residues of honey in pottery and tomb offerings from the New Kingdom period (circa 1550–1070 BCE), including jars from Tutankhamun's tomb, demonstrate the widespread use of honey, often as a sweetener in fermented beverages like wines mixed with fruits or water. Honey was used in ancient Egyptian beverages, with residues found in tombs including Tutankhamun's, but evidence points to it as a sweetener in wines rather than pure fermented honey drinks. Similarly, beeswax residues in West African Nok culture pottery from 3500 years ago indicate early honey collection and processing, suggesting potential for fermented beverages, though direct evidence of fermentation is absent; these practices likely disseminated through regional trade networks to the Horn of Africa. These broader influences, combined with local Aksumite innovations, shaped Tej's foundational methods and cultural significance.
Historical Consumption and Spread
During the Solomonic dynasty (1270–1974 CE), Tej consumption was strictly limited to Ethiopian kings, nobility, and their guests, serving as a marker of elite status and political power in the northern highlands. Commoners were explicitly forbidden from producing or drinking Tej, with honey—essential for its fermentation—collected as tribute or tax from landholders to supply royal and noble households. This exclusivity reinforced social hierarchies, as Tej was served in lavish feasts using specialized vessels like the berele (a horn-shaped bottle) to symbolize rank and authority during diplomatic and ceremonial events. Historical records from the period, including royal chronicles, highlight Tej's role in such contexts, such as at coronations and alliances where it was offered to affirm loyalty and prestige.Early European exposure to Tej occurred through 16th-century Portuguese contact with Ethiopia, but more detailed 19th-century accounts from explorers and envoys documented its first widespread Western tastings. Scottish explorer James Bruce, during his 1768–1773 travels in Abyssinia, described being served Tej daily by Ras Mikael Sehul, noting its presentation in large horns after meals of roasted meats, praising its sweet, fermented profile as a staple of elite hospitality. British and French missionaries, including those from the London Missionary Society in the 1830s–1840s, further recorded Tej in reports on Ethiopian customs, often encountering it during audiences with nobility and emphasizing its cultural prestige over common barley beers. These accounts, published in travelogues and missionary journals, introduced Tej to European audiences as a symbol of Abyssinian sophistication, though initial tastings were limited to diplomatic circles.In the 20th century, following Ethiopia's liberation from Italian occupation in 1941, Tej's production and consumption expanded beyond elite confines, becoming accessible to broader urban populations amid post-war social and economic shifts. The occupation (1936–1941) had disrupted traditional tribute systems, but Haile Selassie's restored rule and early modernization efforts, including urban growth and the rise of tej bet (specialized bars owned by women and serving as social hubs), facilitated wider availability. Tej transitioned from a royal privilege to a popular social drink enjoyed across classes during festivals and daily gatherings, increasingly produced in household settings and sold commercially in cities like Addis Ababa. This democratization reflected broader changes in Ethiopian society, though Tej retained symbolic ties to its noble origins.[9]
Description and Characteristics
Physical Properties
Tej is characterized by a cloudy appearance, presenting as a yellow to golden-amber liquid due to suspended particles originating from honey and gesho during fermentation. This haze arises from residual yeast cells, unfermented substrates, and fine particulates that remain unfiltered in traditional production.[1][10]The alcohol by volume (ABV) of Tej typically falls within a range of 7% to 11%, influenced by factors such as the duration of fermentation, with longer periods allowing for higher alcohol concentrations, sometimes reaching up to 12% or more in certain samples. Variations in ABV across production units can be significant, with mean values reported between 6.98% and 10.9%, and about 58% of samples containing 5% to 10% alcohol.[1][11]In terms of texture, fresh Tej often exhibits a syrupy and slightly viscous consistency attributable to residual sugars from the honey base. As Tej ages, it may become clearer and less viscous, with particles settling to form sediment, though it retains some effervescence from ongoing minor fermentation.[12][13][14]
Flavor and Sensory Profile
Tej exhibits a distinctive balanced flavor profile characterized by the sweetness derived from honey's floral notes, countered by the herbal bitterness imparted by gesho leaves (Rhamnus prinoides). This interplay creates a semi-sweet taste with underlying spice and earthiness, distinguishing it from other honey wines like traditional mead. The bitterness from gesho provides a hop-like edge, preventing excessive cloying sweetness while adding complexity, as observed in traditional preparations where gesho acts as the primary bittering agent.[15]The aroma of Tej is multifaceted, featuring fruity esters produced during fermentation, which contribute notes reminiscent of ripe fruits such as apricot or citrus, alongside prominent herbal and woody scents from the gesho. Floral undertones from the honey—often wildflower or orange blossom varieties—enhance the fragrant bouquet, evoking nectar-like freshness. These aromatic compounds develop through spontaneous fermentation, resulting in a rich sensory layer that varies slightly with honey sourcing but consistently highlights herbal dominance.[15][16]In terms of mouthfeel, Tej is typically effervescent with a light to medium viscosity, offering a semi-sweet sensation on the palate followed by a lingering tannic bite from gesho's phenolic compounds. This texture provides a smooth yet structured experience, with subtle carbonation adding refreshment. Sensory qualities evolve with age; younger Tej, matured for about 2-3 weeks, emphasizes honey-forward sweetness and brighter fruitiness, while extended aging mellows the profile, deepening bitterness and complexity for a more integrated balance.[16][17]
Production
Ingredients
The primary ingredients in traditional Tej production are honey, water, and gesho leaves and stems. Honey serves as the primary source of fermentable sugars, providing the sweetness and nutritional base for fermentation, and is typically sourced from local Ethiopian apiaries using unprocessed, crude varieties to preserve natural yeasts and flavors.[18] Varieties such as Tigray white honey, harvested from the northern highlands and known for its light floral notes from local flora like the Adey Abeba flower, are commonly used for authenticity and regional character.[19] Similarly, honeys from southern regions like Sidamo contribute polyfloral profiles with earthy undertones when incorporated.[20] The honey is mixed with water in a ratio typically ranging from 1:3 to 1:5 (honey to water by volume or weight), which dilutes the sugars to an appropriate concentration for fermentation while influencing the final alcohol content and body of the beverage.[21][22]Gesho, derived from the leaves and stems of the Rhamnus prinoides shrub, acts as a bittering and clarifying agent, similar to hops in beer, imparting tannins and antimicrobial properties that balance sweetness and aid preservation.[18][22] This plant is wild-harvested or semi-cultivated in the Ethiopian highlands, particularly in northwestern and central regions, where it thrives in diverse altitudes and soils, ensuring a supply of fresh, aromatic material essential for traditional recipes.[23]Fermentation in traditional Tej relies on spontaneous yeasts naturally present in the honey and gesho, though modern adaptations may incorporate cultured yeasts for consistency.[22]
Brewing and Fermentation Process
The brewing of Tej begins with the preparation of a honey-water mixture, typically achieved by dissolving crude honey in water in a 1:3 to 1:5 ratio to form a base solution known as berz. This mixture undergoes primary spontaneous fermentation for 2-4 days at room temperature, allowing initial activation of wild yeasts.[24][3]The fermented berz is then filtered through cloth to remove debris. Separately, ground gesho leaves and stems are boiled in water for 15-30 minutes to extract flavors, bitterness, and antimicrobial compounds, after which the gesho infusion is cooled and combined with the filtered berz.[24][25]The mixture is transferred to fermentation vessels for secondary fermentation, relying on wild yeasts such as Saccharomyces cerevisiae and Kluyveromyces spp., along with lactic acid bacteria, converting sugars into alcohol and carbon dioxide. This stage lasts 8-21 days under anaerobic conditions at ambient temperature (around 20-25°C), producing 7-11% ABV.[26][3][24] During this phase, the beverage develops its characteristic turbidity and flavor profile, with sediments forming.Fermentation is followed by an optional aging period in sealed vessels, during which flavors mature; traditional Tej may be aged for months to several years, stabilizing alcohol content and enhancing complexity while residual sugars maintain semi-sweetness. The process concludes with straining through cloth to remove solids, yielding the final honey wine ready for consumption or further maturation.[24]Traditionally, brewing occurs in clay pots known as Insera, which are smoked with gesho leaves and Olea europaea subsp. cuspidata (African olive) wood to impart subtle flavors, inhibit spoilage microbes, and create a controlled microbial environment for wild yeast activation. These earthenware vessels, often stored in cool spaces, promote even fermentation and are integral to home production, where most Tej is made. In modern commercial settings, stainless steel tanks and controlled temperature systems replace clay pots to ensure hygiene, consistency, and scalability while preserving the spontaneous fermentation character.[26][27]
Varieties
Traditional Types
Traditional types of Tej are classified primarily based on fermentation duration and ingredients, which influence the beverage's sweetness, alcohol by volume (ABV), and cultural purpose within Ethiopian traditions. These variations stem from time-honored practices where fermentation is controlled to suit everyday needs or ceremonial significance, using basic ingredients like honey, water, and gesho leaves.Specific named varieties include Laslasa or Berz Tej, a sweet type fermented for 2–3 days without gesho, resulting in a lower ABV of around 7% and retaining significant residual sugars for a milder, more approachable profile suitable for casual daily consumption. This type is typically effervescent and cloudy from active yeasts, offering a refreshing option for informal social settings among households.[28] Sweet Tej undergoes light fermentation for a few days, resulting in a lower ABV of around 7% and retaining significant residual sugars for a milder, more approachable profile suitable for casual daily consumption. This type is typically effervescent and cloudy from active yeasts, offering a refreshing option for informal social settings among households.[17]In contrast, potent or aged Tej, such as Derek Tej, involves extended fermentation lasting months, yielding a higher ABV of up to 11% and a drier, more robust character reserved for rituals and celebrations such as weddings or festivals. The prolonged process enhances potency and complexity, making it a staple in formal gatherings where its strength symbolizes hospitality and tradition. Makakalanya Tej represents a medium-sweet variety, commonly consumed in homes and tej bets.[28][28]These distinctions highlight Tej's adaptability in Ethiopian culture, balancing accessibility for routine enjoyment with reverence in sacred contexts.
Modern and Regional Adaptations
In Ethiopia, Tej production varies regionally, with differences in gesho incorporation influencing the overall bitterness and flavor profile. For instance, in the Amhara region, Tej is typically prepared using red and multiflora honey combined with water extracts from gesho leaves and stems, along with ground wheat, resulting in a distinct nutritional composition that can differ from other areas.[1] These regional adaptations reflect local ingredient availability and traditional preferences, leading to variations in taste intensity across the country.[21]Modern adaptations of Tej have emerged prominently through the Ethiopian diaspora, particularly in the United States and Europe, where commercial production incorporates controlled fermentation techniques to ensure consistency and quality. In the US, for example, Negus Winery in Virginia produces bottled Tej using raw honey and refined modern craft methods, blending family-learned traditional recipes with contemporary brewing practices to create varieties including unfiltered options.[29] This diaspora-driven innovation, influenced by post-2000s migration, has led to the establishment of tasting rooms and nationwide distribution, introducing Tej to broader audiences while preserving its cultural essence.[30]Scientific advancements have further supported these adaptations by developing mixed starter cultures of lactic acid bacteria and yeast for Tejfermentation, allowing for improved quality, safety, and standardization in commercial settings without compromising traditional attributes.[31] In Europe, several commercial brands have appeared since the 1990s, often bottled for retail and restaurant sales, adapting Tej to international palates through refined processes.[32]
Cultural Significance
Social and Ritual Roles
Tej holds a prominent place in Ethiopian rituals and social events, including weddings and religious festivals such as Timkat (commemorating the baptism of Jesus Christ) and Genna (Ethiopian Christmas), where it accompanies communal feasts to enhance celebration and symbolize abundance.[5] In social contexts, tej serves as a key element in family gatherings and communal events, where it is offered to guests as a gesture of hospitality and to strengthen social bonds.[33] Historically reserved for royalty and nobility, its consumption has evolved to foster togetherness in everyday Ethiopian life, often shared during intimate or extended family occasions to promote warmth and connection.[9]Regarding gender and class dynamics, tej production has traditionally been primarily a women's activity, especially in household settings, with tej houses (tej bets) owned and operated by women; men have not traditionally been involved in its making.[9] In some urban areas, young men are increasingly participating in tej production and sales, reflecting broader societal changes.[34] This evolution contributes to tej's role in fostering inclusive communal rituals.
Contemporary Usage
In modern Ethiopia, Tej has experienced increasing commercialization, particularly through dedicated Tej houses in urban centers like Addis Ababa. These tej bets serve as vibrant social hubs where locals gather to enjoy the honey wine alongside discussions and traditional music, reflecting its enduring role in community life.[35]A key development in production occurred with the establishment of commercial brands, such as Nigest Honey Wine produced by Awash Winery in Addis Ababa since the early 2000s, marking one of the first large-scale efforts to bottle Tej for wider distribution.[32] This winery's output contributes to Ethiopia's growing alcoholic beverage sector, with Nigest imported to the United States through specialized shipping services, alongside other Ethiopian brands like Etopi and Saba that have expanded availability as of 2025.[36][37] Exports remain limited but have expanded modestly to markets in North America, driven by demand from the Ethiopian diaspora and interest in traditional African beverages.[5]Among Ethiopian communities abroad, Tej plays a vital role in cultural preservation, often featured in restaurants to evoke homeland traditions. In the United States, for instance, establishments and producers like Negus Winery in Alexandria, Virginia, adapt Tej recipes using local honey while maintaining the use of gesho leaves for authenticity, helping to foster social connections and introduce the drink to non-Ethiopians.[38] Diaspora events, such as Ethiopian New Year (Enkutatash) celebrations in cities like Washington, D.C., and Nairobi, incorporate Tej tastings to mark the occasion and reinforce communal bonds.[39]Rapid urbanization in Ethiopia, with an annual rate of approximately 4-5% in recent decades, has challenged traditional home-based Tej production by limiting access to raw materials and space in cities like Addis Ababa. This shift has prompted hybrid approaches, blending artisanal home methods with commercial ingredients to meet urban demand and ensure consistency.[40]
Serving and Consumption
Traditional Methods
In Ethiopian tradition, Tej is typically poured and served using a berele, a distinctive vase-shaped glassvessel with a wide bowl and narrow neck designed to enhance the drink's floral aromas. This flask-like container, often holding around 240 ml, allows for direct drinking or pouring into smaller portions, reflecting its role in communal settings at tej houses or homes.[41]The beverage is commonly enjoyed at room temperature or slightly chilled to preserve its natural sweetness and effervescence, without the addition of ice to maintain authenticity and avoid dilution.[42][43]Consumption follows a social etiquette of sharing in successive rounds during meals or gatherings, where participants raise their berele in toasts that often invoke blessings for health and prosperity, emphasizing community and hospitality.[44]Due to its potent alcohol content, servings are kept small, with fresh Tej favored for everyday use over more aged, stronger variants reserved for special occasions.[45]
Tej, known for its sweet yet subtly bitter profile derived from honey and gesho, complements spicy Ethiopian cuisine by providing a cooling contrast to intense flavors. It pairs particularly well with doro wat, a fiery chicken stew enriched with berbere spices, where the wine's natural sweetness mitigates the dish's heat without overpowering its complexity.[46] Similarly, Tej enhances kitfo, a preparation of seasoned raw minced beef, by balancing the richness and spice of the butter-infused meat with its honeyed notes.[47]Ethiopian etiquette surrounding Tej emphasizes respect, hospitality, and communal harmony. Serving begins with elders or honored guests, a practice that underscores cultural values of deference to age and status during social gatherings.[44] Refusing an offered cup of Tej is typically viewed as discourteous, as accepting demonstrates appreciation for the host's generosity and strengthens social bonds.[48] In ritual contexts, such as weddings or festivals, participants are expected to consume Tej in moderation to prevent intoxication and preserve the solemnity of the occasion.[49]Among Ethiopian diaspora communities, modern adaptations include pairings with Western-style foods, though pairings with traditional injera-based meals continue to dominate cultural events.[38]
Health Effects
Nutritional Benefits
Tej, an Ethiopian honey wine, derives its nutritional profile primarily from honey, gesho leaves (Rhamnus prinoides), and the fermentation process involving wild yeasts and lactic acid bacteria (LAB). It contains carbohydrates ranging from 3.02% to 3.91%, proteins at 0.10% to 1.38%, and fats at 0.13% to 0.47%, providing a modest energy source through natural sugars like reducing sugars (0.46–2.09 mg/ml) and total carbohydrates (1.49–3.73 mg/ml).[50]Fermentation contributes B vitamins from yeast activity and probiotics from LAB isolates such as Levilactobacillus brevis and Lacticaseibacillus paracasei, which exhibit acid tolerance (survival rates of 18.4%–89.6% at pH 2) and bile tolerance (>50% at 1% bile). These elements support gut health and provide potential immune modulation through antimicrobial activity against pathogens like Shigella boydii and Pseudomonas aeruginosa.[50][52][4]Antioxidants in Tej, stemming from honey's phenolics and flavonoids as well as gesho's bioactive compounds, demonstrate scavenging activities of 37.9%–81.0% (DPPH assay) and 27.4%–73.1% (ABTS assay), offering anti-inflammatory effects that may aid in preventing gastrointestinal disorders and cardiovascular issues with moderate consumption.[53][50]In Ethiopian traditional medicine, Tej is valued for promoting digestion and vitality, with its probiotic and antioxidant components linked to enhanced energy from natural sugars and potential heart health benefits via cholesterol reduction (up to 54% assimilation by select LAB strains).[50][52][4]
Potential Risks and Safety
Tej consumption carries several potential health risks primarily associated with its composition and traditional production methods. The beverage's residual sugar content, derived from unfermented honey, can lead to excessive caloric intake, contributing to weight gain and related metabolic issues when consumed in large quantities.[54] Improper fermentation processes may also result in elevated methanol levels, with some samples exceeding the 0.1% v/v safety limit, potentially causing toxicity symptoms such as visual disturbances and neurological effects.[55] Additionally, as an alcoholic beverage with ethanol content ranging from 7% to 11% v/v—or higher in variably fermented batches—regular consumption raises risks of alcohol dependency, liver damage, and impaired judgment.[56][57]Safety concerns are heightened by the spontaneous fermentation typical of traditional Tej production, which can introduce bacterial contamination and spoilage from pathogens like lactic acid bacteria or molds if hygiene is inadequate.[56] This variability in fermentation dynamics often leads to inconsistent product quality and short shelf life, increasing the likelihood of foodborne illnesses.[53] For commercial Tej products, pasteurization is recommended to eliminate viable microorganisms and ensure stability, thereby reducing contamination risks.[50]In Ethiopia, regulatory efforts to address these issues have intensified since the early 2000s through the establishment of national food safety standards by the Ethiopian Standards Agency. These include hygiene guidelines under ES 929:2021 for safe food handling to prevent contamination, thereby mitigating public health risks like foodborne diseases.[58][59] As of 2025, Ethiopia is drafting legislation to ban alcohol advertising on social media to further curb excessive consumption and related health risks.[60] Despite these measures, enforcement remains challenging for home-produced Tej, underscoring the need for consumer awareness of production sources.
Chemistry
Chemical Composition
Tej, an Ethiopian honey wine, primarily consists of ethanol as its key alcoholic component, typically ranging from 7% to 11% v/v, which develops through spontaneous fermentation of honey-derived sugars.[1] This alcohol level varies based on production conditions, with means reported between 6.98% and 10.9% across multiple samples from traditional units.[54] Residual sugars, predominantly fructose and glucose, remain post-fermentation at concentrations of 0.46–2.09 g/L (as reducing sugars), equivalent to approximately 0.05–0.2%, contributing to Tej's characteristic sweetness, though total carbohydrates can reach 3.73 g/L.[54] Additionally, gesho (Rhamnus prinoides) imparts bitter flavors through compounds such as emodins and other anthraquinones, which are phenolic metabolites present in the plant's leaves and stems used in production.[61][62]The beverage exhibits a pH range of 3.5 to 4.5, reflecting its acidic profile after fermentation, with 77% of samples falling below 4.0.[54] This acidity arises from organic acids, including lactic and acetic acids, with titratable acidity averaging 0.34–0.6 g/100 mL (ranging 0.1–1.03 g/100 mL), produced by lactic acid bacteria during the process.[54]Trace minerals, sourced mainly from honey, include potassium and calcium, with potassium being particularly abundant at levels around 123 mg/L in similar honey wines.[63] Volatile compounds contribute to Tej's aroma, notably ethyl acetate, detected at concentrations of 0.61–1.52 (arbitrary units in headspace analysis), alongside other esters and higher alcohols like fusel oils (13.6–27.4 g/100 L).[3][54]
Fermentation Dynamics
The fermentation of Tej begins with the spontaneous inoculation of wild yeasts, primarily Saccharomyces cerevisiae, which dominate the early stages by metabolizing honey-derived sugars into ethanol and carbon dioxide.[64] As the process advances over 4-6 weeks, a microbial succession occurs, with lactic acid bacteria (Lactobacillus spp., including L. hilgardii and L. paracasei) increasing in prevalence and driving acidification through lactic acid production, while yeast populations stabilize or slightly decline.[3][65] This shift is evident in microbial counts, where yeast levels reach 6.16–6.34 log CFU/mL and lactic acid bacteria rise to 6.37 log CFU/mL by 30 days.[18]During fermentation, sugars like glucose and fructose are primarily converted to ethanol via the glycolysis pathway in S. cerevisiae, theoretically yielding approximately 0.51 g of ethanol per gram of glucose, alongside equimolar production of CO₂ that contributes to effervescence.[3]Ethanol concentrations typically increase from around 10% v/v at 10 days to 12% v/v by 30 days, while residual sugars decrease from 7–10 g/L to 2–5 g/L.[24] Concurrently, pH drops progressively from 3.7–4.2 initially to 3.0–3.3 by the end, enhancing preservation and flavor complexity through the combined actions of yeast and bacterial metabolism.[65][18]Several factors influence these dynamics, including temperature, with an optimal range of 20–25°C promoting efficient yeast activity and preventing off-flavors from excessive bacterial growth.[3] Spontaneous fermentation, reliant on ambient microbes, results in variability in ethanol yield and pH stability across batches, whereas inoculation with selected S. cerevisiae and Lactobacillus strains improves consistency and quality.[3] Additionally, gesho (Rhamnus prinoides) leaves, added mid-process, exert antimicrobial effects against certain spoilage bacteria, selectively favoring beneficial microbes while imparting bitterness.[66]