Gluten, Histamine, Salt, and Charring: What Type of Soy Sauce Should You Absolutely Avoid?

Key Points Summary

Soy sauce is broadly divided into 'honjozo (traditionally brewed)' and 'mixed brewed' methods. It's crucial to always check the label.
Mixed brewed soy sauce (using amino acid liquid) often contains additives like MSG (monosodium glutamate), 3-MCPD, colorings, and sweeteners.
As a fermented food, some products can be high in histamine, so those with histamine intolerance or sensitivity should be careful. Reducing salt content can sometimes lead to an increase in additives.
Charring soy sauce at high temperatures during cooking can not only spoil the flavor but also potentially create undesirable compounds in the charred parts, so be careful not to over-char.
Avoid inexpensive mixed brewed types that list 'amino acid liquid' and many additives. If possible, choose honjozo, whole soybean soy sauce, or those with simple ingredient lists.

Introduction: Is the Soy Sauce You Usually Use Really Safe?

Soy sauce is an indispensable part of our diet, but are you aware that its impact on health can vary depending on manufacturing methods and labeling? When the geefee team compared labels at the supermarket, we were surprised to find significant differences in ingredients and additives even among soy sauces. This time, we'll clearly summarize 'soy sauces to avoid' from the perspectives of gluten, histamine, salt, and charring, along with how to identify them and alternative options.

Types of Soy Sauce and 'What to Watch Out For' — Honjozo vs. Mixed Brewed

What is the Honjozo Method?

The honjozo method is a traditional way of making soy sauce by slowly fermenting and maturing soybeans and wheat with koji mold and yeast. It often matures for over half a year, characterized by rich flavor and fewer additives. Labels indicating 'Honjozo,' 'Saishikomi,' or 'Junsei Shoyu' are generally safer choices.

Risks of the Mixed Brewed Method

In the mixed brewed method, soy sauce can be produced in a short period using ingredients like vegetable protein hydrolyzed with hydrochloric acid (called amino acid liquid) and seasonings (amino acids, etc.). If the label lists many items such as 'amino acid liquid,' 'seasonings (amino acids, etc.),' 'caramel coloring,' or 'preservatives,' there's a possibility of containing umami components like MSG, synthetic additives, and harmful substances like 3-MCPD. While Europe has strict standards for 3-MCPD, products from regions with looser regulations have reported high concentrations, so caution is advised.

Histamine, Gluten, Salt, and Charring: Individual Risks and Practical Measures

Histamine (Relationship between Fermentation and Storage)

Soy sauce is a fermented food, and histamine can be produced during the fermentation and maturation process. Those with histamine intolerance should be cautious of long-term aged products and imported products with unclear ingredient management. We found that products with simple ingredient lists and advertised as short-term aged felt relatively safer.

Gluten (Wheat-Free Doesn't Always Mean Safe)

If you're looking for 'gluten-free' options, you might avoid regular soy sauce (which uses wheat) and choose tamari, rice soy sauce, or liquid amino acids. However, these aren't necessarily low in histamine or additives. Even if tamari is wheat-free, its high fermentation can sometimes lead to high histamine levels, so it's important to check the label and manufacturing method. Those with wheat allergies must always check for 'wheat-free' labels and certifications.

The Pitfalls of Salt Content

Low-sodium soy sauce is popular among health-conscious individuals, but additives (amino acid liquid, seasonings, etc.) are often used to compensate for the reduced umami when salt content is lowered. If you want to reduce salt, consider first reducing the amount used and exploring cooking methods that enhance umami (e.g., using dashi broth).

Charring (Compounds Formed by High-Temperature Cooking)

When soy sauce is heated at high temperatures for a long time and charred, it not only loses flavor but can also form undesirable compounds in the charred parts. It's wise to brown it quickly and be careful with the heat to avoid over-charring. We've also had the experience of charring soy sauce too much on a teppanyaki grill, resulting in a bitter aroma. Honestly, adding it little by little proved practical for controlling the savory aroma.

Practical Checklist: What to Check When Buying and Cooking

Check the label: Prioritize terms like 'Honjozo,' 'Saishikomi,' 'Whole Soybean,' and 'Raw Soy Sauce.'
Terms to avoid: 'Amino acid liquid,' 'Seasonings (amino acids, etc.),' 'Caramel coloring,' 'Preservatives,' and 'Sweeteners.'
For imported products, carefully check the ingredient list as manufacturing methods and safety standards differ.
Those with histamine intolerance or allergies should also check the manufacturing date, aging period, and storage conditions.
When cooking, avoid charring over high heat, add little by little, and supplement flavor with dashi or aromatic vegetables.

Summary

Soy sauce may seem like a simple seasoning, but health risks vary depending on manufacturing methods and additives. Inexpensive mixed brewed soy sauces that use 'amino acid liquid' in particular carry a risk of MSG, 3-MCPD, and various other additives, so it's safest to check labels carefully and avoid them. Also, be mindful of histamine due to fermentation, increased additives in low-sodium versions, and charring during cooking. Since we started making a habit of comparing labels, we've felt more satisfied with both the taste and health aspects. Because it's something we use daily, it's worth taking a little extra effort to choose wisely.

Disclaimer: The information in this article is for general informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional before making any health-related decisions.