Chinese soy sauce may look simple in the bottle, but behind its deep color and savory flavor is a long process of fermentation.
At Kangwang, in Baoying County, Yangzhou, Jiangsu Province, traditional soy sauce brewing combines simple agricultural ingredients with months of fermentation. Some traditional batches take around 300 days to mature, passing through the changing seasons before they are ready.
For people interested in plant-based foods, this process also raises a common question:
Is soy sauce vegan?
To understand the answer, it helps to first understand how traditional Chinese soy sauce is made.
What Is Traditional Chinese Soy Sauce Made From?
Traditional Chinese soy sauce begins with a small number of basic ingredients.
The Kangwang brewing process is based on plant-derived ingredients such as soybeans, wheat, salt and water.
The complexity of soy sauce does not come from a long ingredient list. It comes from fermentation.
Soybeans provide protein, while wheat contributes carbohydrates and aroma. During fermentation, enzymes and microorganisms gradually transform these ingredients, creating amino acids, sugars, organic acids and aromatic compounds.
This natural transformation is what gives traditionally brewed Chinese soy sauce its color, fragrance and rich umami taste.
Step 1: Preparing the Soybeans
The soy sauce making process begins with preparing the beans.
Soybeans are selected, cleaned, soaked and cooked. This softens the beans and prepares their proteins for fermentation.
This stage may appear simple, but good fermentation depends on good preparation.
Soybean proteins will later be broken down into amino acids, which contribute strongly to the savory flavor associated with Chinese soy sauce.
For traditional brewers, every stage affects the final taste.
Step 2: Making Koji
The next important stage is the production of koji, known in Chinese brewing as zhiqu (制曲).
Prepared soybeans and grain are used to cultivate beneficial microorganisms. During this stage, koji mold produces enzymes that later help break down proteins and carbohydrates.
Koji is one of the foundations of naturally brewed soy sauce.
Without this microbial activity, soybeans and wheat would not develop the complex flavors associated with traditional fermentation.
Modern food science can explain the role of enzymes and microorganisms, but traditional Chinese brewers learned to manage this process through generations of practical experience.
Step 3: Fermentation Begins
Once the koji is ready, it is mixed with salt water and placed into fermentation vessels.
At Kangwang, traditional fermentation is closely associated with large outdoor jars and the seasonal climate of Jiangsu.
Salt is essential to the process. It contributes flavor while also helping create an environment in which the desired microorganisms can develop.
From the outside, the fermentation jar may appear quiet.
Inside, however, the ingredients are constantly changing.
Proteins begin breaking down into amino acids. Carbohydrates are transformed into sugars and other compounds. New aromas gradually appear.
This is the beginning of the flavor we recognize as Chinese soy sauce.
Step 4: Around 300 Days of Natural Fermentation
Time is one of the most important parts of the Kangwang soy sauce process.
Traditional batches can ferment for around 300 days, passing through the hot summer season before reaching maturity.
Traditional Chinese brewers sometimes describe this relationship with nature through the expression:
日晒夜露 — "sun by day, dew by night."
Historically, sunlight, temperature, humidity and seasonal change were all part of the brewing environment.
As fermentation continues, the aroma becomes deeper, the color develops and the taste becomes more rounded.
This is why naturally brewed soy sauce cannot simply be understood as a mixture of ingredients.
The fermentation itself creates much of the final character.
For Kangwang: Time is not only part of production. Time is part of the flavor.
Step 5: Tending the Fermentation
Traditional soy sauce is not made by simply filling a jar and waiting.
The fermentation must be observed and managed throughout the aging process.
Brewers pay attention to temperature, aroma, appearance and changes inside the fermentation vessels. Traditional production also involves circulating or managing the fermenting liquid during maturation.
Before modern monitoring equipment existed, experienced brewers relied heavily on their senses.
They watched the fermentation. They smelled it. They tasted it. And they learned when it needed more time.
Today, modern equipment can improve consistency and food safety, but this traditional understanding of fermentation remains an important part of Chinese soy sauce craftsmanship.
Step 6: Extraction and Bottling
When fermentation reaches the desired stage, the liquid soy sauce is separated from the fermented material.
The finished sauce then goes through processes such as adjustment, filtration or refining, sterilization and bottling.
Modern equipment makes these stages safer and more consistent.
However, machinery cannot fully replace the most important part of traditional production: fermentation time.
The months spent developing flavor remain at the heart of the process.
Why Does Fermentation Matter?
Fermentation is what turns simple ingredients into complex Chinese soy sauce.
During aging, proteins are converted into amino acids and other flavor compounds. These contribute to the deep savory taste often described as umami.
Other compounds create roasted, fermented, slightly sweet and aromatic notes.
This is why naturally brewed soy sauce can add more than saltiness to food.
A small amount can deepen braised dishes, stir-fries, marinades, dipping sauces and many other recipes.
The flavor is the result of microorganisms, ingredients and time working together.
Is Soy Sauce Vegan?
So, is soy sauce vegan?
In many cases, yes.
Traditional soy sauce made from plant-based ingredients such as soybeans, wheat, salt and water can be suitable for a vegan diet.
The fermentation process itself does not require meat, dairy or fish. Microorganisms such as koji mold and yeast are widely used in plant-based fermented foods.
However, not every soy sauce product is identical.
Some flavored sauces or compound seasonings may contain additional ingredients. For this reason, vegan consumers should always check the ingredient label of the specific product.
Is Chinese Soy Sauce Vegan?
Many people also search for "is Chinese soy sauce vegan?"
Traditional Chinese soy sauce is often based on plant-derived ingredients, so many products can be compatible with a vegan diet.
Kangwang's traditional brewing process is also based on plant-derived raw materials and does not depend on meat or dairy as part of fermentation.
However, there is an important distinction between a product being made from plant-based ingredients and being officially vegan certified.
Unless a specific product carries a recognized vegan certification, it is better to describe it according to its actual ingredients rather than claim that it is "vegan certified."
Is Vegan Soy Sauce Gluten-Free?
Not necessarily.
Vegan does not mean gluten-free.
Traditional soy sauce often contains wheat. This means a soy sauce can be completely plant-based while still containing gluten.
People with celiac disease or gluten intolerance should therefore look for products specifically labeled gluten-free.
This is an important distinction when comparing Chinese soy sauce, Japanese shoyu and tamari-style sauces.
Tradition Meets Modern Production
Traditional brewing does not mean refusing modern technology.
Today, Kangwang combines traditional fermentation principles with modern food-safety management, production equipment and quality control.
Modern technology can help improve hygiene, temperature monitoring and consistency.
But the basic principle remains simple: good ingredients need fermentation. Fermentation needs careful control. And good flavor needs time.
This balance allows traditional Chinese soy sauce brewing knowledge to continue in a modern food-production environment.
More Than a Bottle of Soy Sauce
The Kangwang soy sauce process begins with simple ingredients: soybeans, wheat, salt and water.
Through koji production, fermentation, seasonal aging and careful management, those ingredients gradually become something much more complex.
For consumers asking "is soy sauce vegan?", traditional brewing also offers a simple lesson: soy sauce made entirely from plant-derived ingredients can naturally fit into a plant-based diet.
For Kangwang, however, the story goes beyond ingredients.
It is about preserving a traditional Chinese soy sauce process in which craftsmanship, fermentation and patience continue to work together.
Behind the bottle are simple ingredients.
Behind the flavor are microorganisms, generations of brewing knowledge — and around 300 days of time.