Asian Fermentation Starters: Ancient Molds Making Alcohol

Aspergillus sake mold
Aspergillus colonies, the bottom two are the species used in sake production from Adrian J. Hunter, CC BY-SA 3.0 , via Wikimedia Commons

When our ancestors wanted to ferment grains and starches, they faced a tricky puzzle. Sugars from grape juice, honey, or sap magically transformed into alcohol without any human intervention. Starchy foods like rice, corn, and grain would not do the same. To resolve this dilemma, societies in Europe, Africa, and Central Asia learned how to convert some starches to sugar by malting or sprouting the grain before fermenting it. Some people in South America learned how to convert the starch to sugar using their own saliva which contains the enzyme amylase. Meanwhile, from the Western foothills of the Himalayas all the way to the remote islands of the Philippines, Asian brewers learned a different technique–they used moldy fermentation starters.

In traditional foodways, malting was rarely used in Asian countries. Instead, the eastern portion of the continent saw generations pass down an obscure tradition of cultivating molds that could convert starch to sugar. These molds were stored in various dried doughs we call fermentation starters. The practice likely originated in China over 4,000 years ago and spread across the continent gradually. Koreans were using the moldy fermentation starters by the year 0. The mycelial molds that assist in making alcohol have been passed down between starters for as many years as the Chinese have made these starters. 

Unique to Asia, brewers have learned to mix cooked or raw staple foods such as rice and barley with ground herbs. They then inoculate the moist mixture with an older starter or they allow wild yeast and molds to take over. If they use older starters, they are practicing invisible selective breeding. After thousands of years, long-term human selection of the best starters has given rise to molds that are uniquely suited for fermentation (and sometimes exclusive to only certain areas or purposes). These particular molds and yeasts are specialists at instigating both saccharification of starch and fermentation of sugar. 

Yeast are still fungi, but the molds in Asian fermentation starters are not single-cellular booze machines and perform very different metabolic functions. Other cultures had clever ways of storing yeast–the Scandanavians used wooden rings soaked in beer to hold inoculum, the Inca stored amylase and yeast in chewed muko wads–but only Asian countries seem to have these well preserved dough-like starters. On top of this, it is quintessentially Asian to use molds in the production of alcoholic beverages. These starters and their molds define the production and flavor of virtually all traditional alcoholic beverages from the Himalayas east.

The Luzhou Daqu Pits providing fermentation starter for one of the largest baijiu distilleries in the world
The Luzhou Daqu Pits providing fermentation starter for one of the largest baijiu distilleries in the world from Nekitarc, CC BY-SA 4.0 , via Wikimedia Commons

Briefly, here are the principal native fermentation starters for a handful of Asian countries:

Qu, China: Likely the original fermentation starter, qu comes in many forms, but was originally made from millet. The basic ingredient is ground, mixed with water, inoculated, and then formed into a cake. Traditional Chinese rice wines and millet beers utilize simultaneous saccharification and fermentation; mold converts starch into sugar as yeast converts sugar into alcohol.

Within the world of Chinese fermentation, there are three related starters: Daqu, Xiaoqu and Fuqu. Daqu, or big qu, is used for both alcohols and vinegars and is usually a cake. It is typically made from peas, barley, or wheat and contains a variety of molds including Aspergillus terreus, Rhizopus oryzae, Rhizopus javanicus, and Amylomyces rouxii, among others (Sakandar). Xiaoqu, or little qu, is physically smaller in grain form and is more consistent microbially. This kind of starter is used predominantly in Guangxi and Shandong provinces (Sakandar). Lastly, fuqu, is most commonly employed in soy sauce production.

Nuruk, Korea: Chinese fermentation starters likely moved to Korea before other Asian cultures. In Korea, nuruk is a dried cake made from uncooked, ground grains (especially barley), water, and an old nuruk inoculum. Ancient Koreans may have left their dough out to airborne molds for spontaneous inoculation. These starters typically contain molds of the Mucorales or Aspergillus genuses which break down the starches in rice for production of traditional alcohols cheongju, takju, and yakju.

Koji, Japan: Japanese koji is moldy rice used in the production of sake. It is granular in form rather than pressed into a cake. Koji is always made by culturing the mold A. oryzae on steamed rice. While fermentation starters in other Asian countries may also contain A. oryzae, Japanese koji is unique in that it only contains this one mold. The best rice for koji production is Yamada Nishiki as it has a starchy core where the mold’s mycelium can take root.

To make koji, Japanese sake-makers steam rice and inoculate it with mold spores. After one day, they move the rice into wooden boxes which they stack in such a way that air can pass through. The air regulates the temperature because the mold releases heat as it metabolizes the rice. After as little as 40 hours there is already enough sugar for yeast to begin growing on the koji. 

Once a brewer adds koji to the fermentation mash or moromi, it provides both amylase and protease which consume the rice. The balance of fermenting yeast and koji in Japanese sake production is delicate, but allows for a high alcohol content. At no point during the fermentation is there too much sugar to discourage the growth of yeast. With these microbes, sake can naturally reach 20% alcohol by volume. 

Sake production tools morimasu
Sake production tools including a morimasu used to spread rice on trays during koji production from Daderot, CC0, via Wikimedia Commons

Bubod, Philippines: Traditional Filipino brewers grind glutinous rice with herbs such as ginger and the root of Bidens pilosa. They inncolate the mixture with older starter to make new bubod. The starter is typically preserved in the form of dried discs. Filipinos use the starter directly with rice to make tapuy, a rice beer, or they can use bubod to ferment rice into a secondary starter called binubudan which they then use to inoculate sugar cane juice in the production of alcoholic basi.

Loog-pang, Thailand: The Thai call their fermentation starter Loog-pang. This starter is based on rice and is also stored in cakes. Brewers commonly use it to make alcohol in the form of lao or sato which are rice wine and sometimes sorghum beer. Thai people also use the starters to make fermented, alcoholic rice called kao-mag in addition to traditional vinegars. These starters are known to contain the yeast Saccharomycopsis fibuligera which also has amylolytic properties like some mycelial molds. 

Banh Men, Vietnam: Vietnamese fermentation starters, banh men, rely on uncooked rice flour, water, herbs, spices, and the inoculation of a previous batch. The resulting cakes can last up to 6 months when kept dry and Vietnamese people use them to make ruou nep which can be either gooey, fermented rice or rice wine. The cakes contain Rhizopus oryzae, Rhizopus microsporus, and Mucor indicus (Thanh).

Ragi, Indonesia: The Indonesian version of the fermentation starter is ragi. To prepare the starter, Indonesians will take rice flour and mix it with herbs such as garlic, cinnamon, chili, or lemon. They crumble old ragi to inoculate the mix. After adding cold water, the preparer mixes the ingredients into a dough and presses it into a flat ball. The balls incubate for 2 days and dry in the sun for 3 more. The starters contain Mucor circinelloides, M. javanicus, M. rouxii, and Rhizopus oryzae. (Saono)

Indonesians predominantly use ragi to make fermented snacks out of rice or cassava called tapé. Some people, particularly the Balinese, collect the water that forms during rice tapé production and make a fermented alcoholic beverage called brem Bali.

Asian fermentation starters
A list of Asian fermentation starters and the molds most common in them from Lee, Cherl-Ho, and Sang Sun Lee. "Cereal fermentation by fungi." Applied mycology and biotechnology. Vol. 2. Elsevier, 2002. 151-170.

This list is not exhaustive. Mongolians use chuzo, Malaysians have jui paing, Ladakhis in India ferment with phabs, while those in Nepal rely on marcha. The near ubiquity of fermentation starters across Asia is startling. 

Each of these starters is made in a traditional way using ancient knowledge. By selecting older starters to inoculate new ones, Asian societies have been cultivating specialized molds, yeasts, and bacteria to fulfill their role in fermentation. This process, besides being microscopic, is not so different from breeding desirable qualities in cattle. 

The selection of good molds is vital not only for efficiency, but also health. Fermenting with fungi runs the risk of introducing mycotoxins into the supply of human food. These toxins, emitted by some of the common molds in Asian fermentation starters, are known to cause cancer among other ailments. Luckily, most studies conclude that there are no traces of mycotoxins in starters that are handled according to traditional food ways. (De la Rosa)

The ignorance of the rest of the world towards fungal fermentations is startling. Asia has known and practiced simultaneous saccharification and fermentation for many thousands of years. Others have had to rely on malting and or simpler sugars for their booze. Wherever you go in Asia, if you stumble across a traditional market, keep an eye out for small balls or bricks of dried dough. These are likely the start of your next drink. 

Ruou Nep wine made from Banh Men in Vietnam
Ruou Nep wine made with Banh Men in Vietnam from Viethavvh at Vietnamese Wikipedia, CC BY-SA 3.0 , via Wikimedia Commons

Sources Cited

Chen, Shuang, and Yan Xu. “Effect of ‘wheat Qu’on the fermentation processes and volatile flavour‐active compounds of Chinese rice wine (Huangjiu).” Journal of the Institute of Brewing 119.1-2 (2013): 71-77.

DELA ROSA, Jared Gabriel Lopez, and Paul Mark Baco MEDINA. “Philippine rice wine (Tapuy) made from Ballatinao black rice and traditional starter culture (Bubod) showed high alcohol content, total phenolic content, and antioxidant activity.” Food Science and Technology (2021).

Kim, Hyun-Soo, et al. “Characteristics of useful fungi isolated from traditional Korea nuruk.” Journal of the Korean Society of Food Science and Nutrition 26.5 (1997): 767-774.

Lee, Ac, and Y. Fujio. “Microflora of Banh Men, a Fermentation Starter from Vietnam.” World Journal of Microbiology and Biotechnology, vol. 15, no. 1, 1999, pp. 51-55. ProQuest, https://www.proquest.com/scholarly-journals/microflora-banh-men-fermentation-starter-vietnam/docview/752695028/se-2?accountid=11752, doi:https://doi.org/10.1023/A:1008897909680.

Lee, Cherl-Ho, and Sang Sun Lee. “Cereal fermentation by fungi.” Applied mycology and biotechnology. Vol. 2. Elsevier, 2002. 151-170.

Limtong, Savitree, et al. “Yeast diversity in Thai traditional alcoholic starter.” Kasetsart J.(Nat. Sci.) 36 (2002): 149-158.

Sakandar, Hafiz Arbab, et al. “Functional microbiota in Chinese traditional Baijiu and Mijiu Qu (starters): a review.” Food Research International 138 (2020): 109830.

Saono, Susono, et al. “Mycoflora of” ragi” and some other traditional fermented foods of Indonesia.” (1974).

Thanh, Vu Nguyen, and Duong Anh Tuan. “Microbial diversity of traditional Vietnamese alcohol fermentation starters (banh men) as determined by PCR-mediated DGGE.” International journal of food microbiology 128.2 (2008): 268-273.

Yang, Siyoung, et al. “Aspergillus oryzae strains isolated from traditional Korean nuruk: fermentation properties and influence on rice wine quality.” Food Science and Biotechnology 22.2 (2013): 425-432.

Yoshizawa, Kiyoshi. “Sake: production and flavor.” Food reviews international 15.1 (1999): 83-107.

Yu, Tae-Shick, et al. “Bibliographical study on microorganisms of nuruk (until 1945).” Journal of the Korean Society of Food Science and Nutrition 25.1 (1996): 170-179.

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