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Modernization of Chhyang production

chyyang drink


Chhyang is a traditional drink that is used heavily in the festivals of Newar society. It is the most common form of alcohol among the various alcohols that is used in Newari culture. It is also used heavily by the Sherpa and Rai societies both culturally and medicinally. Due to the rich culture and beliefs surrounding Chhyang as well as the traditional mindset of people, the production of Chhyang is still done in the traditional manner. While effective, the process is outdated and requires some upgrades. With the advancement in technology, more specifically fermentation technology, the production of Chhyang can be modernized and commercialized. The use of modern technology can help in the production of Chhyang on a much larger scale with more efficiency than ever before.


There are different religious, ceremonial and convivial use of alcohol drinks which reveal their socio-cultural significance for the people and can tell us about their culture and society. Due to diversity, different communities have different ways of making traditional alcoholic beverages. Grains, fruits or vegetables through a process called fermentation is used to make alcoholic beverages. Different types of traditional alcoholic beverages of Nepalese community are: Tongba, Aeylaa, Raksi and chhyang.


Tongba is a popular drink among Rai’s, Limbu’s and Sherpa’s, mostly in the eastern regions of nepal. In order to make tongba, boiled millet is fermented for a week or two. For consumption, a container full brewed millet served and then hot water is added. Alcohol in fermented millet is soaked by the hot water that is drunk through a wooden or metal straw. The straw is traditionally made of a bamboo pipe with a slit at the bottom end to let the brew in, but not the millet. The water is poured in, let to steep, and sucks the mildly alcoholic brew through the straw. When the first fill is consumed, it is refilled with hot water. This can be repeated four to five times. .The combination of alcohol and warmth heats the body quickly and significantly. That is why it is consumed mostly during winter or in cooler places like hilly and mountainous regions to warm the body.


Nepali alcoholic drink- Aeyla, the most popular alcoholic drink in the Newari community is a distilled version of chhyang and bears a heady parallel to tequila. Aeyla is a strong nepali drink, prepared by distillation of a mixture of fermented rice, millet or fruit. Due to its high concentration of alcohol, it is served in a tiny container called Kholchhaa made of brass. It leaves a burning sensation on the throat while people drink it. Quality Aeyla will burn completely with a bluish flame. Aeyla sometimes is also used as a remedy for indigestion, cough and cold, and a little aeyla can be rubbed on sore knees or the back and chest to relieve pain. Aeyla is one of the required drinks on a lot of occasions and it also has different religious and cultural significance in the Newari society. 


Chhyang is one of the most nutritious, traditional and unavoidable drinks in various Nepalese communities mostly preferred by Newars, Sherpas, and Rai. It is made from the fermented barley, millet, corn or rice grains that are boiled and cooled before yeast(Marcha) is added to it. The taste of Chhyang depends upon the time period of fermentation, when Chhyang is kept fermented for 4-5 days then it is of the best quality and has a sweet taste. If the rice is left to ferment for more than 5 or 6 days it tastes bitter and tends to mold. While Chhyang is similar to another nepali alcoholic drink called Raksi, but the difference is that Chhyang is normally cloudy in color and has a mild sour taste much like a mild cider while Raksi is clear.Traditionally, Chhyang is served in brass bowls like utensil instead of glass. There are three colors of Chhyang(white, brown, red). The most accessible type is white Chhyang, the kind that looks milky. This type of commonly used Chhyang is known as Tithon. One batch can be prepared in approximately 1 week. Lesser known are Karthon, a thick brown Chhyang, and Hyaunthon, a red Chhyang. Both are fairly rare. In Newari community Chhyang is called Thon, and Chhyang in the Sherpa language. This is a special drink used by Newari communities during festivals, social events, and family celebrations. Newari farmers prepare  it during the rice planting and harvesting time, and they like to drink it during break from work in the field.  People of the Sherpa community of our country need Chhyang in every phase of their life, even in sacramental rites and rituals. They believe that Chhyang keeps them warm and their spirits high. Chhyang has many healing properties such as for common cold, fevers, allergic rhinitis and because of high calories, vitamin content, beneficial lactic acid bacteria and yeast is considered more as food than an alcoholic beverage.

Traditional Method of preparation of Chhyang

In the traditional process, rice grains are first soaked in water, washed and cooked at 100 ᵒC. Excess water is strained and about 1% by substrate weight of Marcha or Manapu is added. The mixture, which is known as Haja, is then transferred to a container (traditionally made of mud but more recently made of aluminum). The mixture is then kept for two days for saccharification at 28±2° C in aerobic condition. After aerobic fermentation the Haja is then covered in the container by a thin film and the container is made airtight. Traditionally, the container is surrounded by straw or clothes to heat the mixture and proceed with anaerobic fermentation. This is kept for 4 days. The product is known as Poka. After 4 days, water is added to the Poka and the liquid formed is known as Chhyang. The Chhyang is extracted by filtration process. The extraction is done twice or thrice by adding water after each extraction. The residue remaining is known as Kat and can be used to make another type of alcohol.

Flow sheet for preparation of Chhyang

Soaked rice grains with excess water is heated at 100 ᵒC.

When heated, excess water is strained and 1% inoculum (yeast/Marcha) by substrate weight is added.

Then the mixture is transferred to a clay container for saccharification maintaining the temperature at 28 ᵒC for two days in aerobic condition.

After two days time duration, anaerobic fermentation is continued upto 4 days where the temperature is again maintained at 28 ᵒC with the help of clothes or straws and the container is covered with thin film and closed to make air tight for anaerobic condition.

Water is added to the fermented mixture and the liquid formed is called Chhyang. The liquid is separated from the residue with the help of muslin cloth.

After Chhyang is extracted for the first time, for the same batch of rice and inoculum mixture water is added for extraction of Chhyang again.

Modernization of the process

The traditional process of making Chhyang is quite dated and uses old practises such as using straw for heating and using old clay containers. The process can be modernized like many other fermentation processes for more efficient production.

  • First of all instead of clay or wood containers enclosed aluminum or stainless steel tanks can be used which ensures the proper anaerobic fermentation. The use of these tanks can also ensure proper sanitization as compared to using clay containers and are also easier to clean.
  • After the soaked rice grains and sorghum are placed in the mixing tank, water is added and boiled to 100 °C with the help of a more consistent form of heating like electric heaters rather than using heaps of straws. In recent days, to increase the concentration of alcohol, sorghum is added with the rice grains.
  • Marcha (yeast) is added to the strained rice and sorghum. Marcha and rice can be stirred with the help of an automated stirrer and this mixture is maintained at 28±2 °C using a thermostat for two days. For this time period the mixture is aerobically fermented. Nowadays genetically sequenced inoculum are used so as to increase the yield.
  • After the aerobic fermentation the mixture can be transferred to an enclosed fermenter tank which then undergoes anaerobic fermentation. The Haja is heated to 28±2 °C where it is kept for 4 days.
  • Water is added to the fermented mixture after 4 days.The automation can also be applied to the addition of water in the final stages in fixed times which is done manually right now. The milky liquid formed after the addition of water is called the Chhyang and can be separated from the rice mixture from the filtration process. The extraction of the Chhyang can be done using a filter which refines and purifies the final product.
  • The final refined product i.e. Chhyang is then stored at slightly lower than room temperature.
  • At last proper packing helps to ensure the prolong the shelf-life of the Chhyang.

One of the problems with the traditional method is the inconsistent quality and quantity of Chhyang due to approximation of temperature and time. The use of straw and clothes creates inconsistent temperatures which cannot be controlled. This can be remedied by the use of a thermostat and new automated tools.

The process can be carried out in a sort of batch fermentation process. The main difference from batch fermentation being that the residue(Poka) is reused to make more product. 

With the help of modern tools and analytical techniques the traditional way of making beverages has advanced.The process can be carried out in a sort of batch fermentation process. The main difference from batch fermentation being that the residue(Poka) is reused to make more product. 

The key steps that can to be modernized with modern tools that can be used in the production of Chhyang are as follows:

The use of bioreactors:

For the production of Chhyang, a stirred tank bioreactor and an enclosed fermenter made of stainless steel would be sufficient. The stirred tank can be used for mixing the substrate (rice+sorghum) with the inoculum (yeast) and heating the mixture in an aerobic condition whereas the fermenter provides an anaerobic condition.The stirred tank bioreactor contains an automated stirrer and a thermostat for mixing and temperature control. The mixing of the components ensures uniform distribution and thus more uniform product formation. The mixture is transferred between the reactors using inlets and outlets.The enclosed fermenter would also require a thermostat for maintaining a steady temperature of 28±2 °C for anaerobic fermentation. The use of bioreactors makes the process more efficient and simple.

For the mixing process the use of an automated stirrer is required 

For the heating process the use of more consistent forms of heat like electric heater, gas fire space heaters and steam heaters etc.

For the maintenance of temperature the use of a thermostat or a rector with a  jacket where there is continuous flow inlet steam and outlet of cold water which reheated proceeding the same process again. This helps to keep the temperature steady throughout the process.For the addition of water at the final stages, the sensors which detect the level of water in the container can be installed so that after each extraction of Chhyang the container fills up automatically. Water level sensors help to keep the consistency the same for each batch of Chhyang.

Brewing Process:

It is a complex process during which yeast converts carbohydrates into alcohol and carbon dioxide. Thus this requires a series of sensors to monitor a range of parameters during the fermentation process including carbon dioxide, oxygen, pH, pressure. 

pH sensor: This device ensures that the pH level is maintained during the fermentation. Currently in the bioprocess market pH sensors like In Situ Transmissive pH sensors, non-Intrusive reflective pH sensors are available. These sensors deliver accurate response in time and are low maintenance having a precise reading of pH content.

O2 and CO2 sensors: With the help of CO2 and O2 sensors the amount of oxygen uptake and carbon dioxide production in the fermenter is analysed. Real time monitoring of CO2 and O2 indicates the progression of the process. Monitoring the changes in the fermenter improves the productivity. With the sensors like Infrared CO2 sensors and O2 sensors, steam sterilizable CO2 sensors.

3.3 Filtration:

For the filtration process, a pipe can be fitted between the outlet and the storage container with the installation of a filter to obtain Chhyang. The filter consists of a prefilter and a final membrane filter which assures that Chhyang is free from product spoilage microorganisms. In addition, another pipe can be added to redirect the residue back to the reactor for further production.

3.4 Modern storage and packaging methods:

Storage tank: The purified Chhyang which is ready for packaging is stored in a fully sanitized storage tank. The necessary temperature is maintained as mentioned above. Storing the product at required temperature and conditions is very important as it accounts for the final taste. Along with the maintenance of temperature, the storage tank should account for other factors like no direct exposure to sunlight and moderate humidity level. Storage tanks are economical and make the process more efficient. For example water can be heated with the excess heat produced during the brewing process, while the insulated tanks have minimal heat loss.

  • Barrier Containers: Alcoholic Beverages are very sensitive to oxygen and light, both UV and visible. In order to prolong product shelf-life there are several barrier solutions. To improve light and oxygen barrier properties, bottles can be produced with the addition of barrier agents blended with the resin (nylon MXD6, EVOH, oxygen scavengers) or using multilayer preforms (PET+EVOH, PET+Nylon o PET+Nylon+barrier additive).
  • Kegs: PET is increasingly used as an alternative to metal for large kegs, from 5 to 30 litres. PET kegs are disposable, so there is no need to collect the empty containers and clean them before using them again, resulting in savings.

Reasons for modernization of equipment

The equipment modernization process is simple and less costly than a complete replacement. So, whether the equipment needs repairs or if it is not meeting the requirements, the issues would be fixed using modernization. A comprehensive list of reasons for modernization would be as follows:

  • If the equipment is deteriorating to the level that unscheduled shutdowns are being experienced, high production costs are incurred.
  • In case of old machinery, some parts may be rendered obsolete. That means more money has to be paid for spare parts which can also result in long lead times.
  • Used equipment may show excessive wear or even non-compliance with current safety standards and practices. When the equipment has been modernized, the production should increase at faster-operating speeds with better controls or automation. 

Some of the benefits of integrating modern technologies with traditional and ancient processes like production of chhyang are listed below:

  • Ensures the Safety of Workers:

Modern equipment is laced with exceptional added features like compact formats, space-age materials, and digital trip units that ensure the safety of  workers. The equipment has the capacity to withstand high fault current without shutting down the system. This reduces the risk to the workers.

  • Saves Costs Associated with Space Reconfiguration:

By modernizing equipment, the existing switchgear’s footprint is maintained and no space reconfiguration is required, thus saving Lakhs of Rupees. Upgrading equipment works well with tight operating budgets, as it extends the life of the existing equipment.

  • Parts Are More Readily Available:
    Most of the manufacturers working with old equipment have to stop their production whenever their worn-out equipment needs maintenance. A lot of time and money is wasted in procuring spare parts for the older models. Since they are old, the spare parts are difficult to find. This is not the case with modern equipment. Spare parts are easily available, thus making upgrades and repairs affordable, feasible and less time-consuming.
  • Integrates the Latest Technology:
    Plant managers can make smart decisions by embracing new technology. Integrating modernized equipment that facilitates cloud and Iot connectivity ensures smooth operations. This provides a better understanding to manage and maintain critical systems to avoid unplanned downtime.


The process of making Chhyang is still very traditional. The only major update to the process has been the use of aluminum containers instead of clay ones. The process is still very inefficient and has room for a lot of improvements. With the advancement in fermentation technology, the Chhyang making process can be refined and made much more efficient to yield more product of consistent quality. The use of bioreactors and modern equipment allows the mass production of Chhyang using less manpower while modern practices of storage allow the Chhyang to be stored for longer periods of time.


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