The question of whether soy sauce contains MSG is more complex than a simple yes or no answer. The confusion often arises because of the difference between naturally occurring glutamates and added monosodium glutamate, or MSG. The key to understanding this difference lies in how the soy sauce is made.
The Breakdown of Soy Sauce Production
Not all soy sauces are created equal. The two primary methods of production—natural fermentation and chemical hydrolysis—result in very different final products, especially concerning their glutamate content.
Naturally Brewed (Traditional)
Traditional soy sauce is made through a time-intensive process of natural fermentation, often lasting several months.
- Ingredients: Water, soybeans, roasted wheat, salt, and fermenting agents like koji mold are used.
- Process: Enzymes from the koji mold and other microorganisms break down the proteins in the soybeans and wheat. This process releases free amino acids, including glutamic acid.
- Glutamate Source: The glutamic acid naturally combines with the sodium from the salt brine to form naturally occurring monosodium glutamate, which provides the sauce's rich umami flavor. No MSG is intentionally added during this process.
Chemically Produced (Hydrolyzed)
To meet high demand and lower costs, many companies produce soy sauce through a fast, chemical process that takes only a few days.
- Ingredients: Defatted soy proteins or other vegetable proteins are used.
- Process: Proteins are broken down using heat and hydrochloric acid, a process called acid-hydrolysis.
- Glutamate Source: This fast-track method does not develop the flavor complexity of traditional brewing. Therefore, artificial flavorings, colorings, and monosodium glutamate are often added to mimic the natural umami taste. These sauces will typically list 'hydrolyzed soy protein' or 'hydrolyzed vegetable protein' on the label.
Blended Soy Sauce
Some products available on the market are a blend of both traditionally brewed and chemically hydrolyzed sauces. These sauces are often designed to balance flavor with production cost and will contain both naturally occurring glutamates and added MSG.
Natural Glutamates vs. Added MSG
Our bodies metabolize glutamate from either source—natural or added—in the same way. However, there are some important distinctions to consider, particularly for those with sensitivities.
The Umami Experience
Glutamate is the compound responsible for the umami, or savory, taste.
- In naturally brewed soy sauce, the umami flavor is a complex result of hundreds of flavor compounds created during fermentation.
- In chemically produced sauce, the umami is often a more one-dimensional flavor profile, dependent on the added MSG.
Potential Health Concerns
While the FDA considers added MSG safe, some people report sensitivities. For them, the source and amount of glutamate might matter. Chemically produced soy sauce also contains a toxic byproduct called 3-MCPD, a cancer-causing substance that is regulated by health organizations. Naturally fermented sauces, particularly high-quality ones, contain negligible levels of this compound.
Comparison of Production Methods
| Feature | Naturally Brewed | Chemically Produced | Blended (Hybrid) |
|---|---|---|---|
| Primary Ingredients | Soybeans, wheat, salt, water | Hydrolyzed soy protein | Blend of both methods |
| Production Time | Months to years | A few days | Weeks to months |
| Glutamate Source | Naturally fermented | Added MSG | Natural + Added MSG |
| Presence of 3-MCPD | Negligible | Often present | Variable, potentially present |
| Flavor Profile | Complex, rich umami | Simple, can be harsh | Balanced flavor and cost |
| Label Terminology | Often says "naturally brewed" | "Hydrolyzed soy/vegetable protein" | May vary widely |
How to Identify the Type of Soy Sauce
To be sure whether your soy sauce has added MSG, you must read the ingredients label carefully. Here's what to look for:
- Added MSG: If the label lists "monosodium glutamate" or "MSG" as an ingredient, it contains added MSG.
- Hydrolyzed Protein: If you see "hydrolyzed soy protein" or "hydrolyzed vegetable protein," it was made chemically and likely has added flavor enhancers, including MSG.
- Naturally Brewed: Labels indicating "naturally brewed" or ingredients simply listing water, soybeans, wheat, and salt are your best bet for avoiding added MSG. Tamari, a type of naturally brewed soy sauce, often contains little to no wheat and is a good option for those with gluten sensitivities.
Navigating Choices for Your Dietary Needs
Ultimately, the choice of soy sauce depends on personal preference and dietary concerns. Those seeking to avoid added MSG should stick to traditionally brewed sauces and scrutinize the label. For most people, the trace amounts of naturally occurring MSG in fermented soy sauce are not a cause for concern. However, individuals with specific sensitivities or health conditions, such as high blood pressure due to the sodium content, should exercise caution regardless of the glutamate source.
As with any processed food, understanding the production method is key to making an informed decision that aligns with your health goals. For a deeper look into the science of umami and fermentation, consider exploring resources like the Umami Information Center.
Conclusion
In summary, soy sauce does contain MSG, but the source of the MSG is the critical distinction. Traditionally brewed soy sauce develops naturally occurring monosodium glutamate during its lengthy fermentation process. In contrast, chemically produced and blended soy sauces may have monosodium glutamate added intentionally to enhance their flavor profile. Reading ingredient labels is the most reliable method for determining if a soy sauce has added MSG or has been produced chemically with potentially harmful byproducts. For the purest flavor and highest quality, naturally brewed soy sauce is the superior choice, while still being mindful of the sodium content.
