is soy sauce keto

Is Soy Sauce Keto?

Soy sauce, typically used in Asian cuisine, is a low-calorie base seasoning with a distinctive umami flavor. If you are on a keto or keto diet, you may be wondering if this tasty ingredient is a good choice.

The keto diet drastically limits carbohydrates, and some soy sauces contain more carbohydrates than others. This article looks at soy sauce, its carbohydrate content, and whether it is a keto-friendly seasoning.

What is Soy Sauce?

Soy sauce is a salty liquid seasoning traditionally made from the fermentation of soybeans and wheat. It is known to have begun from a Chinese product called “Chiang” more than 3,000 years ago. Similar effects have been developed in Japan, Korea, Indonesia, and Southeast Asia.

is soy sauce keto

It first came to Europe in the 17th century through Dutch and Japanese trade. The word “soy” originated from the Japanese word for soy sauce, “shoyu.” Thus, the soy itself gets its name from the soy sauce.   

The four essential ingredients in soy sauce are soybeans, wheat, salt, and leavening agents like mold or yeast.  Regional varieties of soy sauce can have different amounts of these ingredients, resulting in different colors and flavors.

What’s it About?

There are several types of soy sauce available. They can be grouped according to their production methods, regional variations, differences in color, and flavor.

1. Traditional production:

Traditional soy sauce is produced by soaking soybeans in water and roasting and grinding the grain. The soybeans and wheat are then mixed with a culture mold, most commonly Aspergillus, and allowed to grow for two to three days.

Salt and water, and the entire mixture are left in a fermentation tank for five to eight months, although some types may age longer.

Mold enzymes act on soy and wheat proteins during fermentation, gradually breaking them down into amino acids. Starches are converted to simple sugars and then fermented into lactic acid and alcohol.

High-quality soy sauce uses only natural fermentation. These varieties are often labeled “naturally produced.” The ingredient list generally contains only water, wheat, soy, and salt.

2. Chemical production:

Chemical manufacturing is a faster and cheap method of producing soy sauce. This type is known as acid hydrolysis, and it can create soy sauce in a few days rather than many months.

In this process, the soybeans are heated to 176 ° F (80 ° C) and mixed with hydrochloric acid. This process breaks down the proteins in soybeans and wheat.   

However, the resulting product is less palatable in taste and aroma, as it lacks many substances produced during traditional fermentation. Therefore, more color, salt, and flavor are added to it.

How to Make Soy Sauce

1. Wash and soak the soybeans

Soybeans are small, yellow-beige beans. First, wash 4 cups of soybeans that you can buy at any supermarket. After cleaning and draining them, fill a pot with 18 glasses of water, add the soybeans, and let them soak for 24 hours.

2. Drain, calm, and mash

Soaked soybeans should be swollen twice their original size before going to the cooking stage. Drain off excess water and cook uncovered soybeans in the same pot for at least 4-5 hours over medium-high heat.

A pressure cooker is used if you want the soy to cook quickly. When using a pressure cooker, add 1 cup of soy water and cover the lid—Cook over high heat for 20 minutes.

Once cooked through, mash the soybeans into a smooth paste with a food processor or mortar.

3. Add the wheat flour

Add four cups of wheat flour to the soybean paste. Knead the dough well until the soy is mixed well with the wheat flour. Do not add more water.

4. Let the fermentation begin

Koji is a bacterial culture with the scientific name Aspergillus oryzae that helps to ferment soybean paste. It is usually granulated because it is made with the culture inoculated in the rice grains.

In India, it can easily be bought online. Though, there is no alternative to a Koji snack to start the fermentation of the soy sauce. Sprinkle “koji starter” over wheat and soy batter according to package directions and combine.

This is a crucial step when making homemade soy sauce, as the koji gives it a distinctive flavor. If koji, don’t worry. The alternative (but longer) method was provided last.

5. Put it on a tray and let it rest

Evenly distribute the soy mixture in a 3-inch deep glass or stainless steel pan in a 2-inch layer. Separate the mix into blocks, each 2 to 3 inches apart. Leaving uneven layers can create “hot spots,” causing mold to grow more in some places than others.

You want consistent growth across all blocks. Let the tray sit in a warm, humid place for two days undisturbed. Note that when fermentation begins, the mixture will emit an odor. So put it somewhere that doesn’t bother you.

6. Make a brine

Inside 16 cups of water, dissolve 3 ½ cups of Himalayan pink salt. Stir until the salt is completely incorporated into the water. This brine is essential to protect the soy blocks from the germination of unwanted bacteria on the surface during fermentation.

7. Add the dried soy blocks to the brine and let it settle

Add the dried soy blocks to a large jar and pour the brine over them. Enough room should be at the top so that you can mix it regularly. Put the pot in a warm and humid place where no one will disturb you.

Use a long-handled spoon to mix the contents once a day for the first week and once a week for about 6-12 months. Since it will have a strong fermentation odor, keep the jar tightly covered. The color will intensify and begin to look more and more like soy sauce.

8. Filter and pasteurize homemade soy sauce

The longer you allow the fermentation to continue, the stronger the flavor of the sauce will be. Therefore, you can strain the sauce even after six months or wait 12 months if you want a more intense flavor and a more intense color.

Homemade soy sauce must be filtered and pasteurized to kill any harmful bacteria. Strain through cheesecloth and press the solids with a spatula until all the liquid is removed.

Heat this liquid over medium-high heat at a temperature of 79 degrees Celsius for 20 minutes. When the sauce has cooled, please keep it in the refrigerator in a tightly covered bottle.

9. No Koji? No problem

If the koji, don’t worry. You can still enjoy this sauce, although it will add more time to the process. First, shape the soybean and wheat dough into 1/4-inch-thick rectangular blocks. Keep them out on a damp paper towel and cover them with another wet paper towel.

Then cover them with cling film and place them in a quiet corner of the house to dry for seven days. You will notice there will be mold growing on the blocks. Place them 2 inches apart on a baking sheet and let them dry in the sun for two days.

This will become your “koji” when it is scorched and brown. Now it only remains to pass the blocks to the brine, let them ferment for 5-6 months, filter, and pasteurize. And that is! Your authentically homemade soy sauce, delicious and flavorful!

Type of Soy Sauce

There are several types of soy sauce in Japan.

  • Dark Soy Sauce: Also known as  “Kikuchi shoyu” is the most common type sold in Japan and abroad. It is reddish-brown and has a strong aroma.
  • Light soy sauce: also called “usukuchi,” is made up of more and fewer soybeans. Wheat and has a lighter appearance and a more delicate aroma.
  • Tamari: Made mainly with soy with 10% or less wheat does not contain aroma, and it’s darker in color.
  • Sashiko: produced by breaking down soybeans and wheat with enzymes in an unheated soy sauce solution instead of salty water.
  • Shiro: is produced only with wheat and very few soybeans. It is very light in color. It has a more potent flavor, and many enjoy it as a dipping sauce.
is soy sauce keto

In China, soy-only tamari-style soy sauce is the most common type. However, a more modern production method is more common today. Soy flour and wheat bran ferment for just three weeks instead of several months. This method results in a very different taste than traditional soy sauce.

Chinese soy sauces are most time referred to as “dark” or “light” in English. Dark soy sauce is usually thicker, older, and sweeter and is used for cooking. Light soy sauce is more delicate, younger, and saltier and is most often used for dipping sauces.

In Korea, the most known type of soy sauce is similar to the dark kind of Kikuchi in Japan. It is made solely from soybeans and is mainly used in soups and vegetable dishes.

The tamari-style sauce is frequently made in Southeast Asian countries such as Indonesia, Malaysia, the Philippines, Singapore, and Thailand, but many local variations exist.

Other varieties include thick sauces with sugar, like kecap manis in Indonesia, or added flavorings, like soy sauce with shrimp in China.

Additionally, this process produces some unwanted compounds that are not present in naturally fermented soy sauce, including some carcinogens.

In Japan, soy sauce made using a purely chemical process is not considered soy sauce and cannot be labeled. However, it can be mixed with traditional soy sauce to reduce costs.

In other countries, chemically produced soy sauce can be sold. This is primarily the type of soy sauce that you will find in the small packages that come with takeout meals.

If it contains chemically produced soy sauce, the label will state “hydrolyzed soy protein” or “hydrolyzed vegetable protein” if it includes chemically made soy sauce.

The Nutrient Content of Soy Sauce

Below is the nutritional breakdown for one tablespoon (15 ml) of traditionally fermented soy sauce.

  • Calories: 8
  • Carbohydrates: 1 gram
  • Fat: 0 grams
  • Protein: 1 gram
  • Sodium: 902 mg

This makes it rich in salt, providing 38% of the Recommended Daily Allowance (RDI). Although soy sauce has a relatively high amount of protein and carbohydrates by volume, it is not an essential source of all the nutrients.

Additionally, the fermentation, aging, and pasteurization processes result in a highly complex mixture of more than about 300 substances that make it up to the flavor, aroma, and soy sauce color. These are alcohols, sugars, amino acids like glutamic acid, and organic acids like lactic acid.

The amounts of these substances vary widely depending on the essential ingredients, the strain of the mold, and the method of manufacturing.    It is compounded in soy sauce that is often linked to their health benefits and risks.

Benefits of The Soy Sauce

Research soy sauce and its components have found some potential health benefits, including:

Can reduce allergies: 76 people with seasonal allergies took 600 mg of one component of soy sauce per day and showed improvement in symptoms. The amount that they consumed corresponds to 60 ml of soy sauce per day.

Promotes digestion: 15 people received a soy sauce broth, resulting in increased secretion of gastric juice, similar to the levels that can occur after ingesting caffeine. Increased gastric juice secretion is believed to aid digestion.

Gut health: most of the isolated sugars in soy sauce have been known to have a very positive prebiotic effect on some types of bacteria found in the intestine. This could be beneficial for gut health.

Promote immune system: Research has found that giving mice polysaccharides, a type of carbohydrate found in soy sauce, improves immune system responses.

Can have anticancer effects: multiple experiments in mice have shown that soy sauce can have anticancer and anticancer effects. Research is though needed to see if these effects are also present in humans.

May lower blood pressure: some varieties of soy sauce, such as reduced salt or Korean Panjang was found to lower blood pressure in mice. Studies in humans are still needed. It should be noted that much of this research has only been done in animals or microscopic studies in people and has used large doses of soy sauce or its components.

So, while some of these results seem promising, it is too early to say whether soy sauce can bring significant health benefits when consumed at the level found in the average diet.   

Despite having all these benefits, soy sauce still has some effects when consumed. What are they:

Contains wheat and gluten:
Many people don’t know that soy sauce can also contain wheat and gluten. For individuals who have wheat allergies or celiac disease, this could be problematic.

Researchers have found that both soy and wheat allergens are completely degraded in the fermentation process of soy sauce. With that said, if you’re not sure how your soy sauce was made, you can’t be sure it’s allergen-free.

Japanese tamari soy sauce is often considered a wheat-free and gluten-free alternative to soy sauce. While this may be true, some types of tamari can still be made with wheat, albeit in lower amounts than those used in other types of soy sauce.    It’s essential to check the ingredient label for wheat and look for soy sauce products specifically labeled gluten-free. Most of the major brands offer a gluten-free variety.

Contains amines:
Amines are natural chemicals found in plants and animals. They are often found in higher stale foods, including meats, fish, cheeses, and some condiments.

Soy sauce contains efficacious amounts of amines, including histamine and tyramine. Too much histamine is said to cause toxic effects when consumed in large amounts.

Symptoms include headache, sweating, dizziness, itching, rash, stomach problems, and changes in blood pressure. It has been said that some reports of allergy to soy sauce may be due to a histamine reaction.

It may contain carcinogenic substances:
A combination of toxic substances called chloropropanols can be produced during food processing, including soy sauce production.

One type is known as 3-MCPD, is found in acid hydrolyzed plant proteins, the type of protein found in chemically produced soy sauce.

Research on animal studies has found 3-MCPD to be a toxic substance. In addition, it has been found to damage the kidneys, reduce fertility, and cause cancer.

Due to these problems, the European Union has set a limit of 0.02 mg of 3-MCPD per kg (2.2 pounds) of soy sauce. In the United States, the limit is greater than 1 mg per kg (2.2 pounds). This amounts to a legal limit of 0.032-1.6 mcg per tablespoon for soy sauce, depending on where you live.

It may be high in monosodium glutamate:
Monosodium glutamate (MSG) is a flavor enhancer. It is found natural also in some food naturally and is often used as a food additive.

It is a type of glutamic acid, which is an amino acid that contributes significantly to the umami taste of food. Umami is one of the five primary flavors of food, often found in “salty” food.

Glutamic acid occurs naturally in soy sauce during fermentation and contributes significantly to its exquisite taste.

Additionally, MSG is often added to chemically produced soy sauce to enhance its flavor. In 1968, MSG was associated with a phenomenon known as the MSG symptom complex.

Soy Sauce and The Ketogenic Diet

Although there are many variations of the ketogenic diet, they all involve limiting carbohydrates to promote ketosis. A metabolic state in the body primarily burns fat for fuel rather than carbohydrates.

is soy sauce keto

Research suggests that most people can achieve ketosis by reducing their carbohydrate intake to 10% or less of their daily carbohydrate intake, or around 20-50 grams per day.

Since many soy sauces are low carb, you can enjoy this flavor-enhancing dressing without breaking out of ketosis. Moreover, there are some essential things to consider:

  • Carbohydrate content: The carbohydrates in soy sauce can range from 1 to 15 grams per tablespoon (15 ml). You can check the nutritional fact label to determine how many carbohydrates are in your soy sauce per serving.
  • Portion size: The nutrition label generally lists carbohydrates per tablespoon (15 ml) of soy sauce. For reference, a single package of soy sauce contains about one teaspoon (5 ml) or one-third of a tablespoon. Monitor the amount you use to make sure it is in line with your dietary goals.
  • Carbohydrate allowance: Based on the carbohydrate content of your soy sauce, determine if the serving size you use fits your total carbohydrate for the day. They usually contain added sugar and are likely not keto-friendly.

Have it in mind that soy sauce is a common ingredient in Asian cuisine. Therefore, when eating out, consider ordering a different unsweetened soy sauce to control better the type and portion you consume.

Alternatives to Keto Soy Sauce

Many people replace soy sauce with similar tasting seasonings due to allergies, gluten intolerance, or other dietary issues.

As with the soy sauce itself, some alternatives to soy sauce are more ketogenic than others. Here is the carbohydrate content of several substitutes for soy sauce:

  • Liquid amino acids: When made with soy protein, liquid amino acids contain 0 grams of carbohydrates per tablespoon (15 ml).
  • Coconut amino: Liquid amino acids derived from coconut contain more carbohydrates than most soy sauces. Each tablespoon (15 ml) of coconut amino acids contains approximately 6 grams of carbohydrates.
  • Maggi seasoning sauce: Like light soy sauce, Maggi Seasoning Sauce contains less than 1 gram of carbohydrates per tablespoon (15 ml).
  • Fish sauce: Since a small amount of sugar is usually added, one tablespoon (15 ml) of fish sauce generally contains about 1 gram of carbohydrates or less. The fish sauce contains more sodium than soy sauce, so it is not typically a 1-in-1 alternative.

Just like soy sauce, most soy sauce alternatives can be easily enjoyed on a ketogenic diet, as long as the number of carbohydrates and serving size are considered about the total daily amount of carbohydrates.


Soy sauce can be ketogenic and is acceptable for consumption. But you do well to avoid binge drinking and preferably prepare it yourself to maintain your keto lifestyle goal.

If you want to know more about keto info, please check the following link.

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