August 5th is Fermentation Day! We Dug Deep into the Relationship Between Fermentation and Ramen, Such as Miso and Soy Sauce.

Soybeans and Soy sauce

Hello to all the ramen fans around the world! Are you enjoying a wonderful ramen life? Today, we’ll deliver some intriguing information that might possibly change your perspective on ramen, so please stay with us until the end.
As mentioned in the title, August 5th is designated as “Fermentation Day,” but its concept may be foreign to a large audience since it’s a day that’s unique to Japan. It was established by Marukome Co., Ltd. (known for its miso production) to promote the charm of fermented foods. Surprisingly, August 8th is also “Fermented Food Day,” which was recognized by the Japan Anniversary Association after Manda Fermentation Co., Ltd. (primarily dealing with health foods) applied for its approval. The fact that there are two special days dedicated to fermentation is the inspiration for this article, and we hope to further illustrate the deep connection between Japanese people and fermented food.
By the way, when you hear the term “fermented foods,” what comes to mind, first? Wine? Cheese? Recently, with more people incorporating probiotics into their diets, you might also think of fermented foods like yogurt or kombucha. However, did you know that ramen, the main theme of this blog, has a relation to fermented foods?
Japan, the birthplace of ramen, is renowned as one of the world’s leading treasure troves of fermented foods. Soy sauce, miso, sake, bonito flakes, natto, and many other representative elements of Japanese cuisine are, in fact, often fermented (a good reason for having two commemorative days dedicated to fermentation). As ramen originated in Japan, it’s impossible to avoid some sort of fermentation. So, what is the relationship between fermentation and ramen? That is our main topic for today.


  • Index


■What is Fermentation in the First Place?



Let’s start by academically defining the phenomenon of fermentation. Biologically, it refers to “the process in which microorganisms break down organic substances, obtaining energy, and reproduce, leading to the transformation of other substances.” If you’re confused by that definition, you’re not alone! Instead, let’s use yogurt, one of the oldest fermented foods, as an example to illustrate. Yogurt is produced by adding lactic acid bacteria (microorganisms) to milk (organic material). During this process, the yogurt acquires properties that the milk didn’t originally possess, such as the ability to be stored for an extended period, as well as excellent digestibility and absorption. This is the phenomenon of fermentation. Yogurt is one instance of how organic matter broken down by microorganisms can be favorable for humans. In contrast, if the outcome were to be unpleasant, such as rotting or molded food, it would be labeled as a “decay.” Both fermentation and decay share the common factor of “microbial propagation.” In simpler terms, fermentation is when there’s benefit to microorganisms attaching to food, while decay is when it leads to something undesirable.
The history of humans utilizing fermentation is extensive. For example, records show that yogurt was made in North Africa around 10,000 years ago, during the prehistoric era. Additionally, traces of winemaking were unearthed in the Mesopotamian region and date back 7,000 to 8,000 years ago. From its first use to now, fermentation’s benefits are countless. One of the most intriguing aspects is how humans selectively harnessed fermentation with microbial propagation while preventing decay. Over a long period of time, humans likely experienced countless trial and error with the occasional chance discoveries before they learned to value the convenience and advantages of fermentation. There may be numerous cases of people mistaking decay for fermentation, leading to the consumption of spoiled food and suffering stomach problems. Nevertheless, the phenomenon of fermentation was worth overcoming these challenges. Reflecting upon the long relationship between fermentation and humanity, we can’t help but appreciate everyday items like yogurt and bread (both of which are fermented foods) as something special.


■Benefits of Fermented Foods



In the previous section, we discussed how the phenomenon of fermentation through the intervention of microorganisms brings beneficial changes to food. Now, let’s explore the specific benefits of the fermentation process. One of the primary advantages is food preservation. When society transitioned from a hunter-gather culture to agricultural and pastoral practices, food production increased, along with the demand to preserve surplus food. To explain how fermentation leads to preservation, let’s again use yogurt as an example. During the process of making yogurt, lactic acid bacteria is used to break down the lactose in milk and produce a large amount of lactic acid. As a result, yogurt becomes acidic, creating conditions that suppress the growth of spoilage-causing bacteria (which prefer neutral to slightly alkaline conditions). Understanding this effect, humans incorporated fermentation as an essential means to maintaining their food supply.
Another significant benefit of fermentation is its ability to aid in the digestion and absorption of nutrients. Let’s use soybeans as an example. In regions where obtaining meat or fish were once difficult, soybeans served as a valuable source of protein. However, soybeans contain a high amount of fiber, making the absorption of the protein difficult. This led to the implementation of the method known as natto. During the production of natto, boiled soybeans are fermented with natto bacteria. This process partially breaks down the proteins, facilitating digestion and absorption. The understanding of these biological processes significantly advanced in the 19th century, though people of the ancient world had already empirically grasped and benefited from these effects. It’s truly remarkable to think that they recognized and harnessed such benefits long before modern scientific explanation was available.
Lastly, we must highlight the effect of fermentation in enriching the taste and flavor of food. In fact, this benefit is believed to play the most significant role in ramen. The reason is that the main seasonings commonly used in ramen soup, such as soy sauce and miso, fully benefit from fermentation’s ability to amplify flavor. Both soy sauce and miso are fermented seasonings derived from soybeans, but during their respective fermentation processes, microorganisms break down the proteins in soybeans into amino acids. Since amino acids contain glutamic acid, a source of umami (savory taste), it’s no wonder the rich umami flavor captured hearts. Soy sauce and miso eventually became indispensable seasonings in Japanese cuisine, and when ramen was born in Japan, they became crucial elements in determining the taste of the soup.


■Why are there so many Fermented Foods in Japan?

Soy beans, Soy sause and Miso


As mentioned earlier, Japan has a wide variety of fermented foods and seasonings compared to the rest of the world. From well-known items like sake, soy sauce, and miso to slightly more obscure ones like bonito flakes, salted squid (shiokara), and salted, dried and fermented fishes (kusaya), the list is extensive. Before addressing why Japan was able to create such a diverse array of fermented foods, let’s take a moment to identify the types of microorganisms used in the fermentation process:

  • Bacteria (lactic acid bacteria, natto bacteria, etc.)
  • Yeast (bread yeast, beer yeast, etc.)
  • Mold (koji mold, blue mold, etc.)

Next, let’s briefly touch upon the differences between Western and Eastern fermented foods. In Western cultures, primarily Europe, fermented foods include (but are not limited to) those made from meat, fish, and dairy products. Representative examples include yogurt and cheese (lactic acid bacteria), and wine and bread (yeast). In contrast, many Eastern fermented foods use a specific type of mold called koji mold, during the fermentation process. This technique is distinctive to Eastern Asia, and in Japan, the use of koji mold in fermentation was introduced from China and the Korea Peninsula.
The adoption of fermentation techniques using koji mold is a significant factor in creating numerous fermented foods in Japan. As mentioned earlier, koji mold is a type of fungus, and generally, fungi thrive in environments with high humidity. With Japan’s warm and humid climate, koji mold flourishes, resulting in the widespread production of fermented foods in the country.
Furthermore, what’s particularly intriguing is that the koji mold used in Japan is not the same as the ones historically used in China or Korea, such as Rhizopus or Mucor species. Instead, Japan has unique strains such as Aspergillus oryzae (A. oryzae) and Aspergillus sojae (A. sojae). This distinction plays a significant role in giving Japanese fermented foods an individual taste compared to other fermented foods in Asia. These strains of koji mold made significant contributions to Japanese culinary culture over the years, leading the Brewing Society of Japan to officially recognize them as “National Fungus.” Receiving this recognition from the country indicates that the use of koji mold and its fermentation techniques are considered significant and valued by the Japanese people.


■The Relationship Between Ramen and Fermentation

Close-up of spoon scooping shoyu ramen soup


Up until now, we discussed the reasons for the rich variety of fermented foods in Japan. Now, let’s shift our focus to the relationship between Japanese fermented foods and the ramen born from this unique foundation. First, we want to narrow in on the soy sauce used in the soup. In a previous article (“What is Ramen? How the History and Elements Lead to Modern-Day Ramen”), it was mentioned that when ramen was introduced to Japan by Chinese chefs, they made various attempts to adapt the flavor to Japanese preferences. The intriguing point is that during this process, they chose to use soy sauce produced with Japan’s unique koji mold, which played a crucial role in enabling ramen to go beyond mere imitation of Chinese noodle dishes, and to successfully develop its own Japanese identity.
Furthermore, fermentation is involved not only in the soup, but various aspects of ramen. For instance, the noodle-making process also incorporates an essential maturation step. Resting the noodles for 3 to 5 days enables enzymes like amylase and protease to break down starch and proteins that are present in the wheat flour. As a result, it’s said that the matured noodles have increased sweetness and umami compared to freshly made noodles. This maturation process is heavily influenced by fermentation.

Additionally, did you know that menma, a popular topping in ramen, is also a type of fermented food? Menma is made by fermenting bamboo shoots, known as takenoko, with lactic acid bacteria, providing its unique texture and umami flavor.
Just by taking a quick overview of the components of ramen, it’s apparent how closely the process of fermentation is interconnected with the dish. From this perspective, it can be said that ramen is also supported by the food culture nurtured by fermentation, which humans have cultivated throughout history.
Of course, in our Myojo USA product lineup as well, traditional Japanese fermented seasoning such as soy sauce and miso play a significant role. After reading this article about fermented foods, you might gain a new perspective and a unique impression of the flavors in ramen when trying these products.


Myojo USA products that utilize soy sauce


Myojo USA products that utilize miso



Today, we dug into the charm of ramen from the perspective of fermentation. What are your impressions of this exploration? One particularly fascinating aspect is how Japan’s food culture has been influenced for over centuries by the fermentation of food. It’s interesting to note that soy sauce, a representative ingredient of Japan’s traditional cuisine, was introduced to ramen from China, and this historical flow contributed to ramen’s popularity in Japan. As mentioned in a previous article (“Where is the Ramen Boom in the U.S. Headed? We Made a Bold Guess of its Future!”), ramen’s versatility lies in its ability to adapt to various food cultures. It’s no surprise that ramen has already served as a form of intercultural communication between “Chinese food culture x Japanese food culture” from its very inception.
Through this investigation, we encountered various fermented foods from around the world. Among them, we will introduce a few that might be applied to ramen in the near future.


Tempeh is a fermented food enjoyed in Indonesia for a long time. It’s made by mixing soybeans with Tempeh fungus and allowing it to ferment. It has a block-like shape and a flavor somewhat similar to natto, but without the slimy texture, making it a potential option for those who may not enjoy natto. When it comes to using tempeh in ramen, it could be considered a substitute for protein sources like chashu, other meat, or fish, especially in vegetarian ramen recipes.




Anchovy is made by salting and fermenting prepared anchovies, commonly used as a flavor enhancer in Italian dishes like pizza and pasta. When considering how to apply the concentrated umami of anchovies to ramen, one dish that comes to mind is Bagna Cauda, an Italian dipping sauce used to enjoy anchovies with vegetables. While researching how the umami in anchovies and the flavorful garlic dipping sauce would complement the dipping sauce used in Tsukemen-style ramen, we discovered that such a dish already exists in Japan! Taking a look at this article, the actual dish surpasses our expectations in terms of quality, and it looks very appetizing! Unfortunately, it appears to be a limited-time menu item, so if you are interested after reading this article, we encourage you to try making it at home as a fun and rewarding challenge!

Bagna Cauda


Sour cream

Lastly, we would like to introduce sour cream. Sour cream is a fermented food made by adding lactic acid bacteria to heavy cream. A few years ago, a recipe for “Sour Cream Onion Ramen” gained popularity in Japan, so we wanted to mention it here. Sour cream-flavored potato chips, French onion dip, and similar dishes are classic favorites in the United States, so there is a high possibility that Sour Cream Onion Ramen could gain popularity in the American market!

This concludes today’s article. We’ll be back with more intriguing information for ramen enthusiasts in the next edition, so please stay tuned and look forward to it!


Reference links:

8月5日は「発酵の日」です。夏バテ防止に栄養補給に、日本の発酵食品を!(季節・暮らしの話題 2018年08月05日) – 日本気象協会
8月5日「発酵の日」、8月8日も「発酵食品の日」。お酒にも関係が深い「発酵」についてもっと知りたい。 | 家飲み、おうち居酒屋がもっと楽しくなるブログ
発酵食品 – Wikipedia
麹 – Wikipedia
日本の発酵食品の種類と歴史について | 通信教育講座・資格の諒設計アーキテクトラーニング
なぜ人は発酵食品を作るのか〜発酵食品の仕組みと科学〜|発酵日和 普段の生活で発酵を楽しむ。コツやレシピ満載の発酵Webメディア。
インドネシアの発酵食品「テンペ」とは?絶品レシピ12選も要チェック! – macaroni
リュウジさんの「サワークリームオニオンラーメン」。新しい学びがありました – ていねいな暮らし、あきらめました。
French onion dip – Wikipedia
History of Fermentation Around the World | Stacker
History and Biochemistry of Fermented Foods