Are There Soybeans in Soy Sauce? The Definitive Answer

November 12, 2025 •

4 min read

A traditional, naturally brewed soy sauce contains just four basic ingredients: soybeans, wheat, water, and salt. Thus, soybeans are indeed a crucial component in most varieties of this popular condiment, though significant variations exist in production and ingredients across different brands and styles.

Quick Summary

Soybeans are a core ingredient for most traditionally brewed soy sauces, which also include wheat, salt, and water. Some varieties, like tamari, use only soybeans, while chemically produced sauces use hydrolyzed protein instead of fermented beans, with additives creating a less complex flavor profile.

Key Points

Core Ingredient: The vast majority of naturally brewed soy sauces, including Japanese shoyu, are made with soybeans as a fundamental component.
Fermentation is Key: In traditional soy sauce, koji mold breaks down the soybean protein during a long fermentation process, creating the sauce's distinct umami flavor.
Not All Soy Sauces are Equal: Some cheaper, chemically produced soy sauces use hydrolyzed soy protein instead of fermented soybeans and rely on additives for flavor, color, and aroma.
Gluten-Free Tamari: Japanese tamari is a type of soy sauce often made with a higher proportion of soybeans and little to no wheat, making it a common gluten-free substitute.
The Wheat Factor: While soybeans provide the umami, wheat is also a key ingredient in many soy sauces (like shoyu), contributing to the sauce's sweetness and aroma.
Check the Label: To ensure you are getting a high-quality, fermented product, look for labels that state "naturally brewed" and an ingredient list that includes soybeans, wheat, water, and salt.

The Core Ingredients of Authentic Soy Sauce

For centuries, soy sauce has been made using a short list of natural ingredients. The most important of these are soybeans and a roasted grain, typically wheat, alongside salt and water. The magic, however, lies in the fermentation process driven by koji mold (Aspergillus oryzae or sojae). The koji mold releases enzymes that break down the proteins in the soybeans and the starches in the wheat. This hydrolysis creates the free amino acids, sugars, and organic acids that give soy sauce its complex flavor, aroma, and color. The fermentation process is a slow, natural maturation that can take anywhere from a few months to several years, depending on the desired flavor profile. The result is a reddish-brown, savory liquid that is prized for its deep umami flavor.

The Role of Soybeans and Wheat

In the traditional brewing method, the proteins from the soybeans are essential for creating the savory umami flavor through the action of the koji enzymes. The soybeans are typically cooked by steaming or boiling before being mixed with the wheat and koji culture. Different ratios of soybeans to wheat can alter the final product. For example, the most common Japanese soy sauce, koikuchi, uses roughly equal proportions of soybeans and wheat, while Tamari uses a higher concentration of soybeans and less or no wheat at all. The wheat primarily contributes sweetness and aroma to the sauce. Some cheaper, mass-produced soy sauces use defatted soybean meal, a byproduct of oil extraction, to simplify the process, which can affect the final taste.

The Brewing Process: Traditional vs. Chemical

Not all products labeled as 'soy sauce' are created equal. The method of production heavily influences the ingredient list and the final flavor.

The Traditional Fermentation Method

Traditional brewing is a time-consuming craft that relies on natural fermentation. The process can be broken down into these key steps:

Preparing Ingredients: Soybeans are soaked and steamed, while wheat is roasted and crushed.
Making Koji: The cooked soybeans and roasted wheat are mixed with koji spores and incubated to form a mash called koji.
Fermentation (Moromi): The koji is mixed with a salt brine to create a mash called moromi. This mixture ferments for several months, with lactic acid bacteria and yeast working together to develop flavor.
Pressing: After maturation, the moromi is pressed to extract the raw soy sauce liquid.
Pasteurization and Filtering: The raw sauce is heated to stabilize and clarify the product before bottling.

The Chemical Production Method

In contrast, chemically produced soy sauce is an accelerated process that bypasses fermentation entirely. Instead of soybeans and wheat, it starts with hydrolyzed soy protein, which is quickly broken down with hydrochloric acid. This process takes only a few days and is significantly cheaper. Additives like caramel coloring, corn syrup, and artificial flavor enhancers are used to mimic the color and flavor of traditionally brewed sauce. The flavor is often simpler and harsher, lacking the complexity and depth of fermented soy sauce. These are often found in inexpensive brands and takeout packets. When purchasing soy sauce, looking for labels that say "naturally brewed" or checking for a short, simple ingredient list can help identify a traditionally made product.

Tamari: A Gluten-Free and Soy-Focused Alternative

Tamari is a type of Japanese soy sauce that offers an alternative for those with gluten sensitivities or who prefer a richer soy flavor. While regular soy sauce uses a blend of soybeans and wheat, tamari is traditionally made with only soybeans and no wheat. It is sometimes a byproduct of miso paste production. Because of its higher soybean content and longer fermentation period, tamari has a thicker consistency, a darker color, and a less salty, more pronounced umami taste compared to standard soy sauce. While most tamari is wheat-free, it is crucial to check the label for a certified gluten-free product, as some brands may add small amounts of wheat. Learn more about the differences between tamari and soy sauce.

Comparison of Soy Sauce Types


Feature	Naturally Brewed (e.g., Shoyu)	Chemically Produced	Tamari
Primary Ingredients	Soybeans, wheat, salt, water	Hydrolyzed soy protein, water, salt	Mostly soybeans, salt, water
Production Time	Months to years	Days	Longer fermentation than shoyu
Flavor Profile	Complex, balanced, and rich in umami; salty, sweet, bitter, and sour notes	Overly salty, less complex, sometimes artificial	Rich, deep, prominent soy umami flavor, less salty
Common Use	All-purpose seasoning, marinades, dipping sauce	Budget-friendly option, often in takeout packets	Dipping sauce for sushi/sashimi, gluten-free option, sauces and glazes
Gluten Status	Contains wheat, not gluten-free	Varies; check label for wheat	Often gluten-free, but check label for confirmation
Color	Reddish-brown, transparent	Often darker, more opaque due to caramel color	Darker and richer than standard soy sauce

Conclusion: The Answer is in the Details

To answer the question, "Are there soybeans in soy sauce?", the answer is a resounding yes for almost all traditionally and naturally brewed varieties. Soybeans are a fundamental component, and their fermentation is what creates the rich, complex umami flavor that the condiment is famous for. However, not all soy sauces are created equal. The market offers a spectrum of products, from aged, naturally brewed sauces made with whole soybeans and wheat, to quick, chemically manufactured versions that use hydrolyzed soy protein instead of fermented beans. For those with dietary restrictions, like a gluten allergy, alternatives such as tamari exist, which are often made exclusively from soybeans. By understanding the ingredients and production methods, consumers can make informed choices to find the right soy sauce for their culinary needs and health preferences.

Frequently Asked Questions

No, while traditional soy sauce is made with fermented soybeans, some mass-produced, chemically processed versions use hydrolyzed soy protein instead. It is always best to check the ingredients list to be sure.

Tamari is a Japanese soy sauce that typically contains a higher proportion of soybeans and little or no wheat. This results in a darker, thicker, and richer umami flavor that is often less salty than regular soy sauce, which is brewed with both soybeans and wheat.

Most soy sauce, especially Japanese shoyu, contains wheat and therefore contains gluten. However, wheat-free varieties like tamari are widely available. You must check the label to ensure a product is certified gluten-free.

Traditional soy sauce fermentation involves combining a mix of steamed soybeans and roasted wheat with koji mold. This mash, called moromi, is then aged in a saltwater brine for months or even years, allowing microorganisms to create the complex flavors.

While chemically produced soy sauce is generally safe to consume, it lacks the complex flavor profile of naturally brewed soy sauce and may contain more additives like caramel coloring and corn syrup. Some also contain higher levels of sodium.

No, individuals with a soy allergy must avoid soy sauce and any products containing it, including tamari, as soybeans are the primary ingredient. Soy allergy can cause a range of symptoms, from mild to severe anaphylaxis.

Look for labels that state "naturally brewed" or "traditionally fermented." Check the ingredient list for simple components like soybeans, wheat, water, and salt. High-quality soy sauces generally have a reddish-brown color, a complex aroma, and are not overly salty.