Mongolian pastoralists process raw milk into a wide range of milk products, including cream, butter, butter oil, alcoholic sour milk and various types of dried unmatured cheeses, and are regarded as one of the groups that have developed the most diverse milk processing techniques across the Eurasian continent (Hirata, Reference Hirata2020). In particular, the Sunit and Chakhar groups of Mongolian pastoralists in the central region of the Inner Mongolia Autonomous Region have been reported to engage in highly refined forms of milk processing, such as collecting whey generated during cheese production to distil alcoholic spirits and producing stretchable cheeses (Umesao, Reference Umesao1955; Chagan, Reference Chagan1991). Stretchable cheeses have also been documented among pastoralists in Mongolia and the Tibet Autonomous Region (Hirata et al., Reference Hirata, Uchida, Motoshima and Damdin2007, Reference Hirata, Nan, Ogawa, Ebihara, Bessho and Hoshi2017; Hoshi, Reference Hoshi2025), suggesting that this technique may have diffused from the central Inner Mongolia region. The production of stretchable cheese by pastoralists is extremely rare across the Eurasian continent, and further elucidation requires detailed reporting from a dairy science perspective.
The Heshigten pastoralists engage in livestock husbandry as their subsistence in Hexigten Banner, Chifeng City, located in the central region of the Inner Mongolia Autonomous Region. The name Heshigten is believed to be derived from the Mongolian term Heshig, meaning the ‘imperial guard’ or ‘royal bodyguards’ of Chinggis Khan (Ochir, Reference Ochir2016). During the Qing dynasty period, the Heshigten were organised as part of the Chakhar Eight Banners and played an important military role (Urchi, Reference Urchi1999; Elliott, Reference Elliott2001). Following the establishment of the People's Republic of China, the area was incorporated into Chifeng City. Heshigten, thus, refers both to a place name and to a sub-group of Mongolian pastoralists. Fencing was installed on the grazing lands assigned to each household in 1997, which led to the sedentarisation of the Heshigten pastoralists. Sedentarisation led to seasonal shortages of feed resources during winter and spring, prompting the adoption of supplementary feeding. The Heshigten pastoralists currently reside in permanent concrete houses and conduct milk-processing activities in pastoral grazing tents. The milk processing techniques of the Heshigten pastoralists have not yet been documented, and the milk products they process remain unidentified. Documenting milk processing techniques among the Heshigten pastoralists in the central Inner Mongolia Autonomous Region, where milk-processing techniques have evolved in distinctive forms, is itself of significant academic value. Furthermore, analysis based on measurements of ambient temperature, heating temperatures during milk processing and the pH of milk products enables the interpretation of these practices from a milk-science perspective. It contributes to a deeper understanding of their technical characteristics.
The purpose of this study was to 1) conduct a field survey to document and understand the milk processing techniques of the sedentary Mongolian pastoralists in Darahan Or Sumu, Heshigten Banner, Chifeng City, Inner Mongolia Autonomous Region; 2) clarify their characteristics through comparison with cases from surrounding regions; and 3) analyse these milk processing techniques, which are implemented on the basis of the Heshigten people's indigenous knowledge, from the perspective of milk science. Furthermore, by demonstrating that the Heshigten group processes pasta filata cheeses without using rennet, this study discusses a ‘dual independent origin of pasta filata technique in Eurasia’.
Materials and methods
Study area and survey methodology
A field survey was conducted in August 2025 among the Heshigten group of sedentary Mongolian pastoralists in Darahan-Oor County, Heshigten Banner, Chifeng City, Inner Mongolia Autonomous Region, China (Fig. 1). Following the dissolution of the People's Communes in 1982, land and livestock were allocated to individual households with the transition to the household responsibility system during the 1980s (Bao, Reference Bao2016).
Weather conditions in Hohhot and location of survey households (❶–❺) of the Mongolian pastoralist Heshigten group in Darahan Or Sumu, Heshigten Banner, Chifeng City, Inner Mongolia Autonomous Region, China.
Figure 1 Long description
Map of Inner Mongolia Autonomous Region, China, highlighting Chifeng City and Heshigten Banner. The inset shows Heshigten Banner with Ta Hai Lake and survey locations marked 1 to 5. A graph displays air temperature in Hohhot, with maximum and minimum values ranging from -20°C to 30°C across months. Another graph shows monthly precipitation, totaling 402 mm annually, with peaks in July and August. The map includes a scale bar indicating 50 km and a north arrow for orientation.
Air temperatures in the study area show marked seasonal variation. During the summer months from July to August, daytime maximum temperatures can rise up to 30 °C, whereas night-time temperatures drop to around 16 °C. Minimum temperatures fall below 0 °C in November, and daytime temperatures remain below the freezing point in December. In midwinter, particularly in January, minimum temperatures can drop to approximately −18 °C, indicating severe cold conditions. Minimum temperatures generally rise above 0 °C from April onward. Precipitation occurs mainly during the summer season, and annual rainfall is low, averaging approximately 400 mm. Heshigten Banner is characterised by a desert steppe landscape with sparse woodlands dominated by wild elm.
A total of five sedentary Mongolian pastoralist households were surveyed (Fig. 1, Table 1). Milk processing was observed through participant observation while staying with Household-1 and Household-2 in their tents, and interviews were conducted on related issues. In Household-3, Household-4 and Household-5, the people – all female – responsible for milk processing were interviewed. The interviews were conducted in Mongolian with the assistance of an interpreter, and the lexical items for milk products were Romanised based on the pronunciation of the Heshigten group. No financial compensation was provided to the participating households. To ensure the accurate identification of milk products used locally, orthographic transcriptions were also provided in parentheses following the phonetic transcription upon their first occurrence. Precise documentation of the nomenclature of milk products is of critical importance in fields such as ethnology and cultural anthropology.
Number of livestock and milking animals (head), land area and milk product sales among surveyed households
Table 1 Long description
Five surveyed households are compared by head counts of cattle, sheep, goats, horses, and camels, with milking animals shown in parentheses, plus grazing land, cropland, and whether milk products are sold. Milk product sales are reported by households 2, 4, and 5, and each of these has 5 milking cattle. Non-selling households 1 and 3 have 5 and 1 milking cattle, respectively. Total cattle range from 40 to 120, with the highest in household 1 and the lowest in household 2. Sheep range from 20 to 190, with household 1 highest and household 2 lowest; goats are absent in households 4 and 5 but present in households 1 to 3. Horses range from 10 to 30, and only household 2 reports milking horses, with 2. Camels range from 0 to 20, and only household 2 reports milking camels, with 2. Grazing land spans 3000 to 6000 mu, while cropland is zero for every household; results are descriptive and do not establish that milking counts or land area cause milk sales.
a 1 mu = 99.1736 m2.
To elucidate the distinctive features of the milk processing system of the Heshigten group, a comparative analysis was conducted with the other Mongolian groups. These included the Sunid in the western part of Xilingol League, Inner Mongolia (Chagan, Reference Chagan1991), the Uzemchin group in the northeastern part of Xilingol League (Pulunga and Amurumende, Reference Pulunga and Amurumende1993), the Baarin group in the northern part of Chifeng City (Boyanhesig, Reference Boyanhesig1994), the Chakhar group distributed from the southern part of Xilingol League to Chifeng City (Mizutani et al., Reference Mizutani, Saito, Watabe, Takano and Ariga1997), the Khorchin group in the southeastern part of Tongliao City (Hirata, Reference Hirata2009), the Ordos group in the southern part of Ordos City (Narason, Reference Narason1989) and the Urad group in the southern part of Bayannur City (Narasu and Almas, Reference Narasu and Almas1994).
During the field survey, the temperature inside their tents used for milk processing was measured using a data logger (Ondotori TR-72A2, T&D Corporation, Japan). The pH of the milk products was measured using a portable pH meter (LAQUA twin pH-11B, HORIBA Ltd., Japan).
Surveyed households
Household-1 keeps 130 cattle, 190 sheep, 10 goats, 30 horses and 2 camels. Milk is currently obtained from the cattle. Of the 130 cattle, 70 are females and 48 are lactating cows, although milk is collected from only five animals. Most lactating cows are not milked but are instead left to nurse their calves. This practice is intended to promote greater growth of the young animals, thereby enabling their sale for meat at higher prices in early winter. Milk and milk products are used for household consumption and are not sold. Household-3 follows a similar pattern: milk is obtained only from cattle, milk products are used exclusively for self-consumption, and no milk products are marketed.
Household-2 keeps 40 cattle, 20 sheep, 20 goats, 15 horses and 20 camels. Among these animals, milking is routinely conducted only for five cows. Although horses and camels have occasionally been milked, such practices are not carried out on a regular basis. Since this study examines milk processing techniques that are commonly shared within the local community, the processing of horse and camel milk was therefore excluded from the analysis. Milk and milk products are used primarily for household consumption, although they are also sold upon request. Household-4 and Household-5 follow a similar pattern, with milk and milk products mainly consumed within the household and occasionally sold when requested.
All surveyed households possess grazing lands ranging from approximately 5,000 to 6,000 mu (1 mu = 99.1736 m2). Although these lands were used for year-round open grazing, they have been divided into summer–autumn and winter–spring grazing lands since around 2021. During the summer and autumn grazing period, wild herbaceous plants are harvested and processed into hay, which is then provided to livestock as supplementary feed during the winter and spring seasons. The use of concentrates for livestock began following the installation of fencing on grazing lands in 1997, which accompanied a shift toward sedentarisation. None of the households owns cropland, and concentrates are not produced by the households themselves but are obtained from external markets.
Based on the above circumstances, the five surveyed households milk between one and five cows each. Raw milk is processed primarily for household consumption, although milk products are occasionally sold upon request. Accordingly, this study focuses on the processing techniques and milk products derived from raw cow milk.
Results
Among the surveyed households, only cattle are currently milked on a daily basis. Raw milk is called suu (sü) (Fig. 2). Suu is processed into various milk products through the technique of cream separation processes. The technique of cream separation processes is characterised by the initial processing step of separating cream from raw milk, after which further processing proceeds separately for the cream and the skim milk. This concept constitutes the typological model proposed by Nakao (Reference Nakao1972) for characterising the world's complex milk processing techniques. Within the techniques of cream separation processes adopted by the Heshigten group, two milk-processing techniques are employed: 1) a no-heating cream separation process, in which cream is separated from raw milk without heat pasteurisation, and 2) a heating cream separation process, in which raw milk is heat-pasteurised prior to cream separation.
Milk processing system of the Mongolian pastoralist Heshigten group.
Figure 2 Long description
The flowchart illustrates cream separation processes with two main techniques: heating/cream separation and no heating/cream separation. I-1) Heating/cream separation: - Starts with ′suu′ (raw milk) undergoing heating, scooping and puring, then left to stand. - Produces ′bolson suu′ (skim milk) and ′urum′ (cream). - ′Bolson suu′ leads to ′bolson suunii eedem′ (naturally fermented milk) and ′eedem′ (curd). - ′Bolson suunii eedem′ undergoes heating, press-draining and sun drying to produce ′bishilag′ and ′eezgee′ (cheese), followed by ′shar os′ (whey). - ′Urum′ leads to ′khataasun urum′ (dried cream), which undergoes heating, shaping and draining to produce ′choraa′, ′khorood′ and ′changaldum khorood′ (cheese), followed by ′shar os′ (whey). I-2) No heating/cream separation: - Begins with ′suu′ (raw milk) without heating, left to stand. - Produces ′eedosun suu′ (naturally fermented milk) and ′joohee′ (sour cream). - ′Eedosun suu′ leads to ′eedem′ (curd) with heating, shaping and draining, producing ′choraa′, ′khorood′ and ′changaldum khorood′ (cheese), followed by ′shar os′ (whey). - ′Joohee′ undergoes heating to produce ′chagan tos′ (oily milk product) and ′shar tos′ (butter oil). Additional processes include: - ′Eirag′ (alcoholic sour whey) from raw milk, leading to ′tsagaa′ and ′Mongol arkhi′ (spirits). - ′Shar os′ and ′eiraganii aarchi′ (whey and cheese) from curd, shaping and sun drying, producing ′eiraganii aarool′ (cheese). - ′Shar os′ and ′shar osnii aarchi′ (whey and cheese) from heating, press-draining, shaping and drying, producing ′shar osnii aarool′ (cheese).
No heating cream separation process
Raw milk, suu, is transferred directly into a wooden container immediately after milking without heat pasteurisation and is left undisturbed in a cool place inside the pastoral tent. In mid-August, the ambient temperature inside the tent is approximately 24 °C during the daytime and around 12 °C at night, although it may rise to approximately 28 °C during daytime while food is being cooked on a nearby hearth. When the raw milk is left to stand, a thin yellowish-white layer of liquid cream gradually rises to the surface. This liquid cream is called singu (singge). With continued standing, the surface cream layer becomes progressively thicker, and the portion exposed to air dries and hardens. This form of naturally fermented sour cream, known as joohee (ǰögekei), develops a slight acidity. It is skimmed off using a ladle and transferred to a separate container. From summer to autumn, sour cream is consistently kept on the dining table and consumed according to individual preference, frequently as an accompaniment to bread or other dishes. When added to milk tea, sour cream enhances its flavour and is particularly favoured among the Mongolian pastoralists.
Excess sour cream that cannot be consumed in daily meals is placed in a permeable cloth bag and stored in a cool area inside the pastoral tent, where whey is gradually drained through dehydration. The cloth bag becomes full after 4–6 days of sour cream accumulation. Natural fermentation progresses during storage, and the pH decreases to approximately 4.6. The fermented sour cream is then transferred to a pot and heated over a low heat. It is continuously stirred with a wooden stick to prevent scorching. Continued heating over a low heat for approximately 40 minutes results in the separation of a clear yellow butter oil that rises to the surface, accompanied by a sweet–sour aroma. This butter oil is called shar tos (sir_a tosu), literally meaning ‘yellow oil’. The butter oil is skimmed off with a ladle and transferred to a stone jar known as sholon gan (sirüin γang) for storage. The stone jar is covered with a plate or similar object to prevent contamination by dust. At room temperature, butter oil solidifies and is said to be storable for several years without spoilage. In the past, the large intestine of sheep was commonly used as a storage container for butter oil. A white milk residue remains after the removal of butter oil, and this oily milk product is called chagan tos (čaγan tosu), meaning ‘white oil’. Formerly, the oily milk product was placed in the sheep rumen around December, when temperatures remained below freezing throughout the day, and stored until the end of winter around April, allowing it to be consumed continuously during the winter season. When sugar is mixed into chagan tos, it acquires a pleasantly sweet–sour flavour and is considered highly palatable. It is also common to store butter oil and the oily milk product together in the same stone jar. The oily milk product is mixed with eezgii (egeǰegei) described below and is frequently used together with milk tea. Both butter oil and the oily milk product are frequently stored in freezers for preservation at present.
After the removal of sour cream, joohee, the remaining skim milk is naturally fermented, resulting in coagulation. This naturally fermented milk is referred to as eedosun suu (egedegsen sü), literally meaning ‘coagulated milk’. The degree of fermentation of naturally fermented milk determines the subsequent cheese-making process. When naturally fermented milk is left to stand for approximately 1 day under daytime temperatures of around 24 °C inside the pastoral tent, it becomes slightly coagulated through natural fermentation, with an acidity of approximately pH 5.1. When this naturally fermented milk is gently heated over a low heat at approximately 30–50 °C, it separates into a curd called eedem (egedem) and a yellow-green whey called shar os (sir_a us). The contents of the pot are continuously stirred with a wooden stick to prevent scorching while heating is maintained at low temperature. Whey that rises to the surface is gradually skimmed off with a ladle. After approximately 10 minutes of low-heat heating, when only a small amount of whey remains, the heat is increased to bring the mixture to a boil. The curd, eedem, is then rapidly kneaded together with the remaining small amount of whey using a wooden stick. Through this kneading process, the curd forms into a single cohesive mass. The curd exhibits a high degree of stretchability; when lifted with the wooden stick, it elongates markedly (Fig. 3). While still hot and pliable, the curd is placed into a square wooden mould called khob (keb), shaped and left to stand for further whey drainage (Fig. 4). The resulting cheese is called changaldum khorood (čingγaldum qurud), literally meaning ‘stretchable khorood’. A thin slice of changaldum khorood is commonly kept on the dining table and consumed at breakfast or when hunger arises, often softened again by placing it into hot milk tea and eaten together with the tea. For long-term storage, changaldum khorood is sliced thinly or cut into fine strips and then dried in the sun. This dried, unmatured cheese is referred to as khataasun changaldum khorood (qataγaγsan čingγaldum qurud), literally meaning ‘dried stretchable khorood’, and can be stored at room temperature for several years.
Curd is kneaded and processed into a cheese known as changaldum khorood.
Drainage of a pasta filata cheese, changaradam khorood, using a square wooden mould called a khob.
Next, when the standing time is extended to approximately 1.5 days, or when raw milk is left to stand for about 1 day under slightly higher daytime temperatures of around 28 °C inside the pastoral tent, naturally fermented milk undergoes further natural fermentation and becomes more firmly coagulated throughout. The acidity reaches approximately pH 4.8–4.9 under these conditions. This naturally fermented milk is then gently heated over a low heat at approximately 30–50 °C, resulting in its separation into curd and whey. The whey is gradually removed using a ladle while heating is continued over a low heat. When only a small amount of whey remains, the heat is increased to bring the mixture to a boil, and the curd is rapidly mixed and kneaded with a wooden stick. Although curd forms into a single cohesive mass, its stretchability is low. When pulled with a wooden stick, it extends only slightly and breaks easily. While still hot and soft, the curd is transferred into a square mould, shaped and left to stand for dehydration. The cheese produced through this process is called khorood (qurud). When sliced thinly and sun-dried, khorood becomes khataasun khorood (qataγaγsan qurud), which can be stored for long periods. Thinly sliced khorood is also commonly kept on the dining table, softened by being added to hot milk tea and then consumed together.
When naturally fermented milk, eedosun suu, is left to stand for an extended period of 2–3 days under relatively high daytime temperatures inside the pastoral tent, it coagulates and its acidity increases to approximately pH 4.6. This naturally fermented milk is heated over high heat from the outset, causing it to separate into curd and whey, after which the whey is removed with a ladle. The resulting curd exhibits no stretchability. It is shaped into pieces approximately 3–5 cm in size and left to drain. The cheese produced at this stage is called choraa (čur_a). When sun-dried, it becomes khataasun choraa (qataγaγsan čur_a), which can be stored for long periods. Furthermore, cheese, khorood, is also produced from naturally fermented milk whose acidity has increased to around pH 4.6. In this case, raw milk is added to the naturally fermented milk to adjust the pH back to approximately 4.9. Subsequent steps of heating, shaping, draining and drying follow the same procedures as those used for khorood. When warmed, this khorood also exhibits slight stretchability.
Cheeses are clearly differentiated according to the degree of lactic acid fermentation of the curd among the surveyed Heshigten pastoralist households. The differences between changaldum khorood and khorood lie primarily in the degree of natural fermentation and the degree of coagulation. Changaldum khorood is produced by heating the curd at a semi-coagulated stage (pH 5.1), whereas khorood is processed by heating the curd at a fully coagulated stage (pH 4.8–4.9). As a result, changaldum khorood exhibits high stretchability and a softer texture than khorood. When lactic acid fermentation of the curd proceeds excessively, the product becomes choraa, in which stretchability is completely lost and the cheese is instead processed into a hard product through drying. Even when fermentation has advanced to such an extent, the Heshigten pastoralists adjust the acidity by adding raw milk to restore the pH to approximately 4.9, thereby enabling the production of stretchable khorood. This practice demonstrates a refined empirical control of fermentation processes based on indigenous knowledge.
Heating cream separation process
Raw milk is poured into an electric rice cooker, and heating is initiated by switching to the high-heat cooking mode. At present, rice cookers are used to produce a cream called urum (örüm_e), whereas in the past milk was heated in a pot using livestock dung and small branches of wild elm as fuel. Because a rice cooker allows finer adjustment of the heating temperature, this appliance has increasingly been adopted for cream production in recent years, particularly since around 2022. Once the milk begins to boil, it is repeatedly scooped up and poured back using a ladle. After approximately 30–50 repetitions, the surface of the milk becomes covered with foam. This foaming process of the milk surface is referred to as saamarakho (samurqu), and is considered a crucial step in cream production. When the surface is fully covered with foam, the cooker is switched to the low-heat mode and the milk is warmed at this temperature for approximately 8 minutes. The cooker is then returned to the high-heat mode for approximately 2 minutes. This cycle of warming and heating is repeated in a calm, draft-free location until the surface foam collapses, a process that takes roughly 1 hour. After all surface foam has disappeared, the milk is kept warm for an additional 1 hour. Heating is then stopped overnight, and the milk is left to stand at room temperature to allow the cream to rise. If the scooping process is conducted in the morning, the milk is left until evening; if conducted in the evening, it is left until the following morning. The container is placed in a freezer the next morning for approximately 3 hours to cool and solidify the risen cream. A cream layer approximately 0.5–1.0 cm thick forms on the surface. This cream is carefully lifted by hand, allowing the inner surfaces to fold over one another and is known as urum. The cream is frequently consumed by adding it to milk tea or spreading it on bread. It may also be placed on a perforated plate and dried in the shade to enhance storability. The dried product is called khataasun urum (qataγaγsan örüm_e). In recent years, the cream has also been preserved by freezing. Although cream was formerly heated to produce butter oil called shar tos, this practice is no longer carried out at present.
The skim milk remaining after the removal of cream is called bolson suu (boluγsan sü), literally meaning ‘milk cooked by heating’. Skim milk is further processed using two different methods. The first method involves allowing skim milk to stand for 2–3 days to undergo natural fermentation. This naturally fermented milk is called bolson suunii eedem (boluγsan sün-ü egedem), commonly abbreviated to egedem in everyday usage. When naturally fermented milk is heated over a high heat in a pot, it coagulates. The curd produced at this stage is also referred to as bolson suunii eedem or eedem. The whey, shar os, is ladled off, and the curd remaining at the bottom of the pot is placed into a cloth bag and pressed between stones or wooden boards. It is then left overnight to promote dehydration. The resulting dehydrated cheese is called bishilag (bisilaγ), which is sliced thinly before consumption. Furthermore, most of the whey is removed, and naturally fermented milk, together with the remaining small amount of whey, is further heated and concentrated in the pot. This concentrated cheese is spread flat on a plate and sun-dried, producing a cheese called eezgee. The second method is employed to accelerate the production of bishilag and eezgee through the use of a coagulant. In this process, either highly acidified whey that has undergone lactic acid fermentation or eirag described below is used as the coagulant. The skim milk, bolson suu, with a pH of approximately 6.6, is heated in a pot, and fermented whey with a pH of around 3.7 is added. This reduces the pH of skim milk to approximately 5.6, causing rapid coagulation. The curd produced by this technique is also called bolson suunii eedem. Subsequent processing into bishilag and eezgee follows the same procedures as those applied to bolson suunii eedem derived from natural fermentation.
Utilisation of whey
When naturally fermented milks such as eedosun suu or bolson suunii eedem are heated, whey called shar os was produced. The collected whey is transferred to containers and subsequently used for the production of a cheese known as shar osnii aarool (sir_a usun-u aγaruul) and for the processing of a distilled spirit referred to as Mongol arkhi (Mongγul ariki).
Shar osnii aarool is produced exclusively from whey generated during the processing of naturally fermented milk, eedosun suu. The whey is left to stand for several days to promote lactic acid fermentation, increasing its acidity to approximately pH 4.7. According to local informants, allowing the whey to stand for several days results in a higher yield of shar osnii aarool. The acidified whey is heated in a pot and brought to a boil while being stirred, during which a whitish coagulum forms. The mixture is transferred to another container and left undisturbed at room temperature for about half a day. A white curd then settles at the bottom of the container. This curd is called shar osnii aarchi (sir_a usun-u aγaruul). The curd is collected and placed in a cloth bag, where it is left to drain for approximately 2 days. A weight is then placed on the bag, and dehydration is continued for a further 2 days. After dehydration, the cheese mass is removed from the cloth bag, shaped by pressing it through the fingers and dried in the sun. The resulting product is shar osnii aarool. Shar osnii aarool is a white cheese produced primarily from whey proteins with relatively mild acidity. Although it is often consumed within a few days, it can also be stored for longer periods.
All whey produced during the processing of naturally fermented milks, eedosun suu and bolson suunii eedem, is used in the production of spirits, Mongol arkhi. A specialised vessel known as eiregeen gan (ayiraγ-un γang) is used for alcoholic fermentation. A portion of alcoholic sour whey called eirag (ayiraγ) from a previous batch is retained in the vessel as a fermentation starter, to which newly produced whey and raw milk are added. The whey is warmed to approximately 45 °C and then poured into the vessel. The addition of raw milk is said to promote both lactic acid and alcoholic fermentation. The resulting mixture has a pH of approximately 3.7 and a temperature of around 30 °C. To maintain warmth, the vessel is wrapped in cloth and placed adjacent to the hearth so that residual heat from cooking can be transferred. During fermentation, the mixture is intermittently stirred with a stirring rod, performing nine stirring motions per set. As fermentation proceeds, vigorous bubbling is observed. When whey is added in the morning, alcoholic sour whey is produced by the following morning. Once the surface of the alcoholic sour whey becomes foamy, it is considered ready for distillation. For distillation, the foaming alcoholic sour whey is transferred to a pot, over which a cylindrical distillation tube called bulkhuur (büligür) is placed. A cooling vessel called jalabuchi (ǰilabči) is mounted on top, and beneath it a collecting container called tosuura (tosuγur) is suspended to receive distilled spirits. The junctions are tightly wrapped with cloth to prevent vapour leakage. Cold water is added to jalabuchi and replaced as needed to ensure effective condensation. Livestock dung and small branches are used as fuel. This process yields a distilled spirit with an alcohol content of approximately 11% and a pH of around 3.3, characterised by a pronounced sourness. The distilled spirits, Mongol arkhi, are stored in lidded earthenware or glass containers to prevent alcohol evaporation and are commonly consumed during social gatherings or used as gifts for relatives and/or friends. After distillation, a whitish, semi-liquid curd known as tsagaa (čaγ_a) remains in the pot. When allowed to stand, a white curd settles at the bottom. This curd is collected, placed in a cloth bag, weighed and left to drain for several hours, producing a cheese known as eiragnii aarchi (ayiraγ-un aγarča). After draining, the cheese is removed from the cloth, thinly sliced, shaped and sun-dried to produce eiragnii aarool (ayiraγ-un aγaruul). This dried cheese is extremely sour. This cycle of processing is repeated from May to October, during which both spirits and eiragnii aarool are continuously produced. Distillation ceases in October. From that time onward, alcoholic sour whey is kept in a warm place, with additional whey and raw milk periodically added to maintain fermentative activity, serving as a starter culture for the following year's distillation. This fermentation starter is referred to as khurung (körüngge).
Discussion
Non-adaptation of fermentation processes and development of cream separation processes
Milking and milk processing are estimated to have originated in West Asia around 10,000 years ago (Vigne and Helmer, Reference Vigne and Helmer2007). It has been hypothesised that, after the development of the technique of West Asian-style fermentation processes producing storable milk products such as butter oil and dried unmatured cheeses, these practices spread widely from Western Asia across the Afro-Eurasian continent (Hirata, Reference Hirata2020). The West Asian-style fermentation processes are one of the milk processing techniques, in which the raw milk is first fermented before sour milk is churned to make butter. Butter is heated to make butter oil and soured buttermilk is heated, curdled, drained and sun-dried to make dried unmatured cheese. Both butter oil and dried unmatured cheese can be stored at room temperature for several years. This technique of fermentation processes also corresponds to one of the typological models proposed by Nakao (Reference Nakao1972). It is assumed that this technique, which originated in West Asia, spread widely across the Afro-Eurasian continent and formed the basis for subsequent milk processing techniques (Hirata, Reference Hirata2020). The technique of West Asian-style fermentation processes has indeed been transmitted to northeastern Mongolia (Hirata, Reference Hirata2024). However, its application tends to remain largely confined to the processing of raw milk into sour milk or alcoholic sour milk, and to the production of dried unmatured cheese through the heating, draining and sun-drying of sour milk in Mongolia and the Inner Mongolia Autonomous Region (Umesao, Reference Umesao1955; Chagan, Reference Chagan1991; Boyanhesig, Reference Boyanhesig1994; Badamkhatan, Reference Badamkhatan1996; Miaki, Reference Miaki1996; Konagaya, Reference Konagaya and Ishige1997; Hino, Reference Hino1998; Hirata, Reference Hirata2002; Hirata et al., Reference Hirata, Uchida, Motoshima and Damdin2007). In this respect, the technique of fermentation processes in these regions exhibits a tendency towards simplification.
While the technique of fermentation processes was simplified, there is a tendency in the North Asian region for the development of cream separation techniques (Hirata, Reference Hirata2002). The air temperature inside tents in mid-August was approximately 24 °C during the day and around 12 °C at night. Wulijideligen et al. (Reference Wulijideligen, Hamada, Yoshimura, Ono, Tsognemekh, Sudun and Miyamoto2013) sampled fermented mare's milk from Mongolia and Inner Mongolia, and analysed its microbial communities. Their results showed that the only thermophilic lactic acid bacterium present was Streptococcus thermophilus, whereas several mesophilic lactic acid bacteria were identified, including Lactococcus lactis, Leuconostoc mesenteroides and Lactobacillus curvatus. The optimum temperature for fermentation of many mesophilic lactic acid bacteria used in cheese fermentation is approximately 20–30 °C, and their fermentation rate is slower than that of thermophilic lactic acid bacteria (Johnson, Reference Johnson and Donnelly2014). In cool climatic regions, lactic acid fermentation progresses slowly, and cream rises to the surface before fermentation advances sufficiently to coagulate the milk during the standing period. As a result, the technique of cream separation processes inevitably develops in these regions. It was reported that the technique of cream separation processes is highly developed in both Mongolia and the Inner Mongolia Autonomous Region (Konagaya, Reference Konagaya and Ishige1997; Hirata, Reference Hirata2020, Reference Hirata2024). The milk processing system of the Heshigten group relied exclusively on the technique of cream separation processes. Milk products essential for daily life, such as cream, butter oil, several types of cheese and distilled spirits, were produced using only two processes: heated cream separation and unheated cream separation. The milk processing system of the Heshigten group can thus be regarded as consistent with the milk processing techniques widely practised across Mongolia and the Inner Mongolia Autonomous Region. Furthermore, the production of stretchable cheeses with particular attention to the management of the acidity of curd is primarily observed in the southern part of the Sunid group area in Xilin Gol League, as well as in the Khorchin group area in the southern part of Tongliao City, both located in the central part of the Inner Mongolia Autonomous Region (Chagan, Reference Chagan1991; Hirata, Reference Hirata2009). The case of the Heshigten group, characterised by specialisation in the technique of cream separation processes, the absence of sour milk processing and the production of distilled spirits and stretchable cheeses from whey, can therefore be considered a distinctive feature of the milk culture in central Inner Mongolia.
Utilisation of whey
The Heshigten group utilised whey known as shar os for the production of cheeses such as shar osnii aarool and eiragnii aarool, as well as for the production of distilled spirits. The whey used for shar osnii aarool was derived exclusively from the whey generated during the processing of curd known as eedem into changaldum khorood, khorood and choraa. Shar osnii aarool can be regarded as equivalent to whey-protein cheeses, such as Italian ricotta. Ricotta cheese is produced by adjusting the pH to approximately 5.8–6.0 and heating the whey to 80–90 °C (Mangione et al., Reference Mangione, Caccamo, Natalello and Licitra2023). Thus, ricotta production requires both acidic conditions and heat-induced protein denaturation of whey proteins. When the Heshigten group heated naturally fermented milk known as eedosun suu to separate it into curd and whey, the heating temperature was maintained at approximately 30–50 °C. Whey proteins are sensitive to heat: denaturation gradually begins at around 60–70 °C, accelerates rapidly above 70–80 °C as the tertiary structure collapses and at 80–90 °C most proteins aggregate through intermolecular bonding (Dannenberg and Kessler, Reference Dannenberg and Kessler1988; Akkerman et al., Reference Akkerman, Rauh, Christensen, Johansen, Hammershøj and Larsen2016). Heating at 30–50 °C during curd formation allows whey proteins to be recovered without thermal denaturation, representing a temperature range favourable for collecting whey intended for whey-cheese production. On this basis, it can be concluded that shar osnii aarool constitutes a cheese analogous to ricotta. Moreover, the low-temperature heating during curd formation can be interpreted as a practice that effectively enhances the recovery yield of shar osnii aarool, a cheese based on whey proteins.
The production of the distilled spirits known as Mongol arkhi utilised whey not only generated during the preparation of changaldum khorood, khorood and choraa, but also whey produced in the processing of bishilag and eezgee. The organic substrates required by yeast for alcoholic fermentation are carbohydrates. Because lactose can be recovered in whey regardless of the heating temperature applied during curd processing, whey generated at any stage of cheese making, irrespective of heating conditions, can be used for distilled spirits. The Heshigten group used all whey generated during milk processing for the production of distilled spirits, and their milk processing practices can, therefore, be regarded as scientifically valid from the perspective of milk science. Among many pastoral societies across the Eurasian continent, whey is used primarily for purposes such as leather tanning or feeding dogs. In contrast, the use of whey for alcoholic sour milk has been particularly well developed among Mongolic pastoralists in Inner Mongolia (Umesao, Reference Umesao1955; Hirata, Reference Hirata2020).
Hence, it can be concluded that Mongolic pastoralists in Inner Mongolia, including the Heshigten group, maximise milk utilisation by using whey not only for cheese making but also for the production of fermented and distilled spirits. The indigenous knowledge of milk processing among the Heshigten group can be regarded as being grounded in techniques that are scientifically valid from a milk science perspective.
Dual independent origin hypothesis of pasta filata technique
The distinctive feature of milk processing techniques in the central part of the Inner Mongolia Autonomous Region is the production of pasta filata cheeses. Pasta filata cheese refers to a category of stretchable cheeses in which the pH of the curd is adjusted to approximately 4.9–5.4, after which the curd is heated, kneaded and stretched to form a fibrous structure (Kimura et al., Reference Kimura, Igoshi and Murayama2007; Niro, Reference Niro2010; Fusco et al., Reference Fusco, Chieffi and De Angelis2022). The term pasta filata is derived from the Italian word pasta, meaning dough, and filare and filatura, referring to the actions of kneading and stretching. The name reflects the process by which hot water is added to the cheese curd and the dough is subsequently kneaded and stretched.
Changaldum khorood produced by the Heshigten group can be regarded as a pasta filata cheese, as the curd acidity is adjusted to approximately pH 5.1 and the cheese is subsequently heated and kneaded to develop a fibrous, stretchable structure. When lifted with a wooden stick, the cheese exhibits characteristic extensibility, which is typical of pasta filata cheeses. Khorood can also be classified as a type of pasta filata cheese; however, since the curd undergoes slightly more lactic acid fermentation, reaching a pH of 4.8–4.9, its stretchability is reduced. In the case of choraa, the curd undergoes further fermentation, resulting in a lower pH of approximately 4.6. Although it is heated in the same manner as changaldum khorood and huruuda, choraa does not exhibit stretchability. Nevertheless, even when the curd has over-fermented to a pH of 4.6, the Heshigten group restores the pH to around 4.9 by adding raw milk, and subsequently heats and kneads the curd to produce a proper pasta filata cheese. Changaldum khorood and khorood are identical to the milk product referred to as Sun khorood in other regions, and the processing methods employed correspond to the same technical procedures. The production of stretchable cheeses has been documented in the southern Sunid region and the Khorchin area in central Inner Mongolia (Chagan, Reference Chagan1991; Konagaya, Reference Konagaya and Ishige1997; Hirata, Reference Hirata2009), as well as in Tibetan pastoral areas of Qinghai Province and the Tibet Autonomous Region (Hirata, Reference Hirata2004; Hirata et al., Reference Hirata, Nan, Ogawa, Ebihara, Bessho and Hoshi2017). In Mongolia, Sun Khorood is produced in some regions; however, this practice is considered to have been transmitted from Inner Mongolia (Hirata et al., Reference Hirata, Uchida, Motoshima and Damdin2007). Geographically, this production is observed among the Sunid group in the western part of the Xilingol League, the Chakhar group extending from the southern part of the Xilingol League to Chifeng City, and the Khorchin group in the southeastern part of Tongliao City, all of which are located in central Inner Mongolia (Fig. 5). In all cases, these groups apply milk processing techniques based on a no heating cream separation process, in which raw milk is left to stand and undergo natural fermentation, with pasta filata cheese subsequently produced by regulating the degree of fermentation of the naturally fermented milk (Chagan, Reference Chagan1991; Mizutani et al., Reference Mizutani, Saito, Watabe, Takano and Ariga1997; Hirata, Reference Hirata2009). Furthermore, the production of pasta filata cheese has also been documented in Tibetan pastoral areas of Qinghai Province and the Tibet Autonomous Region (Hirata, Reference Hirata2004; Hirata et al., Reference Hirata, Nan, Ogawa, Ebihara, Bessho and Hoshi2017; Hoshi, Reference Hoshi2025).
Geographical distribution of pasta filata cheese production in Inner Mongolia. Only the techniques involved in the production of pasta filata cheese were extracted from each milk processing system.
Figure 5 Long description
Cheese production techniques in Inner Mongolia, focusing on cream separation processes and pasta filata cheese production. It includes several groups: Baarin, Uzemchin, Urad, Ordos, Khorkchin, Sunid and Chakhar, Heshigten and Chifeng area. The Baarin, Uzemchin, Urad and Ordos groups are noted for not producing pasta filata cheese. The Khorkchin group follows a process where raw milk (suu) is left to stand, leading to naturally fermented milk (uusun suu) and sour cream (urum). These are further processed into whey (shar os), pasta filata cheese (sun khorood), oily milk product (joohee) and butter oil (shar tos). The Sunid group uses raw milk (suu) to produce naturally fermented milk (eedem) and sour cream (joohee), which are processed into whey (shar os), cheese (eezgee), pasta filata cheese (sun khorood), oily milk product (shinge) and butter oil (shar tos). The Chakhar, Heshigten and Chifeng area group follows similar processes, producing naturally fermented milk (eedosun suu) and sour cream (joohee), leading to whey (shar os), pasta filata cheese (sun khorood), oily milk product (tsutsgii) and butter oil (shar tos). Each group is associated with specific researchers and years, indicating the source of the information.
Similar pasta filata cheeses are produced in other parts of Eurasia using rennet, including mozzarella in southern Italy; kashkaval in Bulgaria and other parts of the Balkans (Satric et al., Reference Satric, Miloradovic, Mirkovic, Mirkovic and Miocinovic2013; Hirata and Yotova, Reference Hirata, Yotova, Hirata and Rakshieva2017; Sulejmani and Hayaloglu, Reference Sulejmani and Hayaloglu2017; Hirata et al., Reference Hirata, Yotova and Yamada2024); jibne shilal in Syria (Hirata, Reference Hirata2022); chechil in Armenia; and sulguni in Georgia (Petrosian and Underwood, Reference Petrosian and Underwood2006).
Hence, across the Eurasian continent, pasta filata cheeses are predominantly produced in two regions: the Inner Mongolia–Tibetan Plateau and the Eastern Mediterranean. Differences exist in the use of coagulants such as rennet, and pasta filata cheeses have not been documented in Central Asia and the Indian subcontinent. These observations suggest that pasta filata technique was independently invented in the Eastern Mediterranean and the Inner Mongolia–Tibetan Plateau. Accordingly, this evidence supports the hypothesis of a ‘dual independent origin of pasta filata technique in Eurasia’, with two separate centres of origin for this cheese-making tradition. Further research is required to examine the hypothesis, including more detailed investigations of pasta filata techniques on the Tibetan Plateau, as well as studies to determine the presence or absence of pasta filata processing in Central Asia and the Indian subcontinent.
Acknowledgements
The authors owe a great deal of thanks to the local settled Mongolian pastoralists in Darihanwula Sumu, Hexigten Banner, Chifeng City, Inner Mongolia Autonomous Region, China, for offering their hospitality and kindness. We received linguistic assistance from Prof. Yasuhiro Yamakoshi of the Tokyo University of Foreign Studies in the orthographic transcription of milk products.
Author contributions
Masahiro Hirata conducted the field investigation, analysed the data, and wrote the original manuscript. Narigan, who is from the study area, facilitated and coordinated the fieldwork, assisted with data collection, and reviewed and verified the information presented in the manuscript.
Declaration of interest
The authors have no competing interests.
Funding statement
This research was funded by the 2025 fiscal year's Grant-in-Aid from the Japan Society for the Promotion of Science, Japan (Project Number: 22K01097).
Ethics and approvals
Prior to each interview, the purpose and procedures of the study were explained to the participants, and informed consent was obtained verbally from all participants. Participation was voluntary, and participants were informed that they could decline to answer any question or withdraw from the study at any time. To protect participants' privacy, personal identifying information was removed from the interview records and manuscripts. Participants were informed that the interview data would be used for academic research. The study was conducted in accordance with the ethical guidelines of Obihiro University of Agriculture and Veterinary Medicine.
