Soy Sauce & Tamari - Complete Reference

February 26, 2026

Soy Sauce © kvalifood.com

Soy sauce is one of the oldest and most versatile condiments in the world - a deeply savory, umami-rich liquid that has been seasoning food across East and Southeast Asia for over 2,000 years. Made from fermented soybeans, it brings saltiness, depth, and complexity to everything it touches: stir-fries, marinades, braises, dipping sauces, glazes, and broths. A splash can round out a sauce, a marinade can transform a piece of meat overnight, and a small bowl on the side can elevate the simplest meal.

Tamari is its close cousin - richer, darker, and made with little to no wheat, making it the go-to choice for those avoiding gluten and for anyone who wants a deeper, rounder flavor.

What most people don’t realize is that “soy sauce” is not a single thing. There are dozens of regional styles across Japan, China, Korea, and Southeast Asia - each with a distinct flavor, saltiness, color, and purpose. Knowing which one to reach for makes a real difference in the kitchen.

Types of Soy Sauce
Tamari - Deep Dive
Culinary Applications
Quality, Brands, and Buying Guide
Storage and Shelf Life
Substitutions
How Soy Sauce Is Made
Industrial vs. Traditional Production
Nutrition
Flavor Chemistry
Origins and History

Types of Soy Sauce

Japanese (Shoyu)

Japan has five officially recognized styles under the JAS (Japanese Agricultural Standards):

1. Koikuchi (濃口) - “Thick Mouth”

Most common (~80% of Japanese production)
Deep reddish-brown; well-balanced between saltiness, sweetness, umami, and aroma
Made with roughly equal parts soybeans and wheat
The default “Japanese soy sauce” most people know
Salt: ~16-17%
Brands: Kikkoman, Yamasa

2. Usukuchi (薄口) - “Thin Mouth”

Lighter amber color but saltier than koikuchi (~18-19% salt)
Less aroma; used when you want seasoning without darkening the dish
Often contains amazake (sweet rice wine) or mirin
Dominant in Kansai (Osaka/Kyoto) cuisine
Common mistake: people assume “light” = less salty. The opposite is true.

3. Tamari (溜まり) - see Tamari - Deep Dive

4. Shiro (白) - White Soy Sauce

Very light gold/amber color
Made with mostly wheat, very little soy
Delicate, slightly sweet, subtle umami
Used in high-end Japanese cooking where color must not be introduced (chawanmushi, clear soups, delicate sauces)
Short shelf life; oxidizes and darkens quickly after opening
Produced mainly in Aichi prefecture

5. Saishikomi (再仕込み) - Twice-Brewed / “Refermented”

Moromi is brewed using previously made soy sauce instead of brine
Much more complex, darker, richer, and more expensive
Very thick and deeply savory
Best used as a dipping sauce or finishing condiment; cooking heat wastes the complexity
Also called kanro shoyu (甘露醤油) - “sweet dew soy sauce”

Chinese Soy Sauce

Chinese soy sauces are typically wheat-free or low wheat, made from soybeans + roasted grain (sometimes), and tend toward a different flavor profile - less sweet, more savory and sharp.

Light Soy Sauce (生抽 - Sheng Chou)

Thin, reddish-brown
All-purpose seasoning; used for stir-fries, marinades, dipping
Saltier than dark
The default Chinese cooking soy sauce

Dark Soy Sauce (老抽 - Lao Chou)

Aged longer; often has caramel or molasses added
Very dark, thick, slightly sweet
Used primarily for color in braises, red-cooked dishes, noodles
Lower saltiness than light; would undersalt a dish if used alone

Double Dark / Black Soy Sauce

Even thicker and darker than lao chou; more molasses
Common in Southeast Asian Chinese cooking (Malaysian, Singaporean)
Kecap manis (Indonesian) is essentially an extreme version of this category

Superior Soy Sauce

A premium light soy sauce made from first-press liquid
Used in high-end Cantonese cooking as a finishing sauce

Mushroom Soy Sauce

Light or dark soy sauce infused with straw mushroom extract
Deeper, earthier umami; popular in Chinese-American cooking

Korean Soy Sauce (Ganjang, 간장)

Korea has a parallel fermentation tradition using meju - brick-shaped blocks of dried, fermented soybeans inoculated with naturally occurring molds and bacteria (not just controlled koji).

Joseon/Guk-Ganjang (조선간장 / 국간장) - Traditional

Lighter amber color, sharper and saltier
Byproduct of doenjang (Korean fermented soybean paste) production; contains no wheat
Very different flavor from Japanese/Chinese - more mineral, fermented-funk notes
Used in soups (guk) and light seasoning

Yangjo Ganjang (양조간장) - Brewed

Modern style, brewed using Japanese-influenced methods with koji and wheat
Darker, milder, more similar to koikuchi shoyu
Everyday Korean cooking soy sauce

Southeast Asian Styles

Kecap Manis (Indonesia)

“Sweet soy sauce” - thick, almost syrup-like; can contain up to 50% palm sugar (gula jawa)
Originated on Java in the 19th century - Chinese fermentation techniques adapted to local tastes
Defining condiment in Indonesian cuisine: nasi goreng, satay, babi kecap
Not interchangeable with regular soy sauce in cooking without adjusting sugar

Kecap Asin (Indonesia)

“Salty soy sauce” - closer to Chinese light soy sauce
Thinner and saltier than kecap manis

Toyo (Philippines)

Filipino soy sauce; often lighter and slightly less complex than Chinese/Japanese
Paired with calamansi for dipping (toyomansi)

Thai Soy Sauce (Si-Ew)

Si-ew khao (white/light): all-purpose
Si-ew dam (black): sweet, used for color; similar to kecap manis but less sweet

Tamari - Deep Dive

What Makes It Different

Tamari is made with little to no wheat - 90-100% soy - giving it a distinctly different character from regular Japanese shoyu.

Factor	Koikuchi Shoyu	Tamari
Wheat	~50% of grain	None or trace (<5%)
Soy ratio	50/50 soy:wheat	90-100% soy
Protein content	Moderate	Higher
Fermentation	6-18 months	Often 12-24 months
Pressing method	Mechanical press	Often traditional fune press
Moromi texture	Pourable mash	Very thick, almost solid

Flavor Profile

Thicker viscosity - coats surfaces better, clings to food
Darker color - very deep mahogany/brown
Richer, rounder umami - higher glutamic acid content due to higher soy protein
Less sharp, less sweet than koikuchi
More complex finish - less volatile brightness, longer persistence
Some describe a slight wine-like depth or chocolatey quality in premium tamari

The absence of wheat aromatics makes tamari taste “quieter” but deeper. Side-by-side tasting: koikuchi is bright and punchy; tamari is dark and resonant.

Gluten-Free Considerations

Traditional tamari contains no wheat. However:

Many modern commercial tamaris add a small amount of wheat (often 3-10%) - always check the label
Certified gluten-free tamari (e.g., San-J) is tested to <20 ppm gluten - the FDA threshold
In Japan, labeling is less rigorous for gluten-free claims; cross-contamination in shared facilities is a real concern
For strict celiac needs: buy explicitly certified GF tamari from dedicated producers

Key Tamari Producers

San-J (Japanese-American, produces in Japan): Most widely available GF tamari in Western markets
Ito Shoten (愛知県): Premium traditional producer in Aichi; very small batch, aged 2+ years
Marukin: Established Aichi producer
Yamaki: Traditional Aichi producer, makes both regular and premium tamari

Origins

Tamari originated as the liquid that accumulates (溜まる, tamaru) and drains from miso during its fermentation and pressing. The origin story traces to 1254 (Kamakura era), when the Zen monk Kakushin returned from China with the Kinzanji method of miso-making and taught it to villagers in Kishu Yuasa (Wakayama). He noticed that the liquid seeping out of the fermenting miso tasted exceptional - that liquid became tamari.

Traditional miso production in Japan - particularly in the Chubu region (Aichi, Mie, Gifu prefectures) - continued to produce this liquid as a valuable byproduct. Over centuries, producers began deliberately crafting moromi to maximize this liquid, effectively making tamari on purpose.

Culinary Applications

Matching the Right Soy Sauce to the Application

Application	Best Choice	Why
Stir-fry seasoning	Koikuchi / Chinese light	Good balance, can take heat
Adding color to braises	Chinese dark / lao chou	Color first, low saltiness
Dipping sauce (sashimi, dumplings)	Koikuchi or tamari	Tamari for richer dip
Marinades	Koikuchi, tamari	Penetrates protein, tamari clings better
Glazes	Tamari, saishikomi	Thickness, depth, less burning
Clear Japanese soups/chawanmushi	Shiro (white)	No color contamination
Finishing/table sauce	Saishikomi, premium tamari	Complexity wasted by cooking
Ramen broth (tare)	Koikuchi or blended	Backbone flavor
Indonesian rice dishes	Kecap manis	Correct flavor profile
Korean soups	Joseon/guk-ganjang	Traditional flavor
Gluten-free cooking	Certified GF tamari	Direct 1:1 substitute

Heat and Cooking Behavior

Don’t add soy sauce early to high-heat wok cooking - the volatile aromatics evaporate rapidly; much of the complexity is lost
Adding at the end of cooking preserves aroma; adding early deepens color and saltiness
For maximum flavor layering: use a small amount early (for Maillard/umami base) + a finishing splash at the end (for aroma)
Tamari and saishikomi are more heat-stable than shiro or delicate usukuchi

Pairing Logic

Soy sauce’s umami amplifies other umami sources through glutamate + nucleotide synergy:

+ Dashi (inosinate from bonito): explosive umami
+ Mushrooms (guanylate): very deep, earthy umami
+ Tomato (glutamate): redundant umami but compatible
+ Fat: Umami compounds are fat-soluble; soy sauce penetrates marbled meat very effectively
+ Acid (rice vinegar, citrus): Acidity brightens and lifts; balances soy sauce’s weight

Quality, Brands, and Buying Guide

Reading a Japanese Soy Sauce Label

本醸造 (Honjozo): Fully naturally brewed - quality minimum
天然醸造 (Tennen Jozo): Naturally brewed without temperature control - traditional, higher complexity
Look for fermentation time: 1年 (1 year), 2年 (2 years), etc.
No additive symbols: 無添加 (no additives), 無化学調味料 (no chemical seasonings)

Tiers and Notable Producers

Japanese Koikuchi:

Entry: Kikkoman (ubiquitous, consistent, honjozo)
Mid: Yamasa, Higashimaru
Premium: Kishibori Shoyu (18-month, cedar barrel), Kamebishi (2-3 year, unusual koji-less method using mugi/barley), Yamaroku (4-year cedar barrel)

Tamari:

Accessible: San-J (widely available, GF certified), Kikkoman Tamari
Premium: Ito Shoten (Aichi, very limited export), Marukin

Chinese:

Light: Pearl River Bridge (Superior Light), Lee Kum Kee Premium Soy Sauce
Dark: Pearl River Bridge Dark, Lee Kum Kee Dark Soy Sauce

Kecap Manis:

ABC Kecap Manis (Indonesian standard), Bango (high quality, uses palm sugar)

What to Avoid

Any product listing “hydrolyzed soy protein” or “hydrolyzed vegetable protein (HVP)” as a main ingredient without also saying “naturally brewed”
Very cheap soy sauces - often largely or entirely HVP-based
Soy sauce in plastic bottles that’s been on a grocery shelf for unknown time - oxidation significantly degrades flavor

Storage and Shelf Life

Unopened

Shelf stable for 2-3 years at room temperature in a dark place
Traditionally brewed soy sauce has higher natural preservative compounds (organic acids, ethanol, salt) that extend shelf life

After Opening

Storage	Shelf Life	Notes
Room temperature	3-6 months	Flavor degrades faster; fine for frequent use
Refrigerator	Up to 2 years	Recommended; significantly slows oxidation
Tamari/premium sauces	Refrigerate immediately	Higher fat/protein = faster degradation
White (shiro) shoyu	Refrigerate; use within 3 months	Very oxidation-sensitive

Signs of Degradation

Color darkening significantly (oxidation)
Loss of aroma - smells flat or musty
Cloudiness or sediment (some sediment is normal in unpasteurized sauces; cloudiness with off-smells is spoilage)
Soy sauce does not typically “go bad” in a food safety sense due to high salt, but flavor quality degrades meaningfully

Substitutions

If you need	And only have	Use this substitution
Tamari	Koikuchi shoyu	Direct 1:1; slightly less rich, more wheat-forward
Koikuchi shoyu	Tamari	Direct 1:1; slightly brighter, less thick
Chinese light soy sauce	Koikuchi	1:1; koikuchi slightly sweeter/less sharp
Dark soy sauce	Koikuchi + sugar	1 tsp dark ≈ 1 tsp koikuchi + ½ tsp brown sugar + extra for color
Usukuchi	Koikuchi + salt/water	Very imperfect; different flavor profile
Soy sauce (any)	Coconut aminos	1:1 to 1.5:1; significantly less salty, slightly sweet; works for GF/soy-free
Soy sauce (any)	Fish sauce	½ to 1:1; no wheat/soy, similar umami but totally different flavor

How Soy Sauce Is Made

Core Ingredients

Ingredient	Role
Soybeans	Primary protein source → amino acids → umami
Wheat	Sugars for fermentation → aroma, sweetness
Salt	Preservation, salinity, controls microbial activity
Water	Brine medium
Koji mold (Aspergillus oryzae / A. sojae)	Enzyme production

Tamari uses little to no wheat.

Stage 1 - Koji Cultivation (2-3 days)

Steamed soybeans (and roasted, crushed wheat) are inoculated with koji spores and spread on flat trays in a temperature- and humidity-controlled room. The mold grows through the grain and produces a library of enzymes:

Proteases → break proteins into peptides and free amino acids (especially glutamic acid = umami)
Amylases → break starches into fermentable sugars
Lipases → break fats into fatty acids (contribute to aroma)

The resulting cultured grain is called koji (麹).

Stage 2 - Moromi Fermentation (months to years)

Koji is mixed with salt brine (~17-20% salinity) to form a thick mash called moromi (諸味). This is where the long fermentation happens.

Multiple microbial populations work in sequence:

Lactic acid bacteria (Tetragenococcus halophilus) - salt-tolerant, lower the pH, produce organic acids, create a stable environment
Yeasts (Zygosaccharomyces rouxii, Candida spp.) - produce ethanol and hundreds of aroma compounds
Ongoing enzymatic activity - proteases continue converting proteins to glutamates throughout

The moromi is stirred periodically (traditionally with wooden paddles) and darkens progressively through oxidation and Maillard reactions.

Fermentation duration:

Industrial: 3-6 months
Traditional/artisanal: 12-36 months
Premium (e.g., saishikomi): up to 3 years

Stage 3 - Pressing

The mature moromi is pressed to separate the liquid from the solids. Methods range from modern mechanical presses to traditional cloth-lined wooden boxes weighted with stones (fune pressing). The pressed liquid is called nama shoyu (raw soy sauce).

Stage 4 - Pasteurization and Finishing

The raw soy sauce is heated to ~70-80°C to stop microbial activity, deactivate enzymes, and trigger a final burst of Maillard browning that deepens color and flavor.
Filtered for clarity.
Optionally blended, aged further, or adjusted with sugar/caramel (for dark styles).

Industrial vs. Traditional Production

Chemical/Acid Hydrolysis (HVP)

The cheapest and fastest method. Defatted soybean meal is treated with hydrochloric acid at high heat, breaking proteins into amino acids. The acid is then neutralized with sodium carbonate.

Time: ~3 days total (acid treatment is hours; neutralization, filtration, and blending add time)
Cost: Very cheap
Flavor: Flat, harsh, one-dimensional - only provides glutamate saltiness, none of the hundreds of fermentation-derived aroma compounds
Issues: Can produce 3-MCPD (3-monochloropropane-1,2-diol), a carcinogenic byproduct; heavily regulated in EU. A 2001 UK FSA study found 22% of tested HVP-based soy sauces exceeded safe limits - the worst sample was 700× over the EU threshold. Naturally brewed soy sauce contains negligible 3-MCPD.
Labeling: Often listed as “hydrolyzed soy protein” or “HVP”

Blended Production

Many commercial brands use a blend: fermented shoyu base + HVP to cut costs while maintaining some fermentation complexity. Widely used in mid-tier commercial products.

Traditional Brewing (Honjozo)

In Japan, honjozo (本醸造) is the legal designation for fully naturally brewed soy sauce, with no HVP additions. This is the quality benchmark.

Nutrition

Per 1 tablespoon (15ml), typical koikuchi shoyu:

Nutrient	Amount
Calories	8-10 kcal
Sodium	900-1,000 mg (~40% DV)
Protein	~1g
Carbohydrates	~1g
Glutamic acid	~150-200 mg free

Sodium

Soy sauce is high in sodium - the primary health consideration. Reduced-sodium versions typically cut sodium by 40-50% using various methods (dilution + flavor enhancement, or post-fermentation desalting). They sacrifice some flavor complexity.

Tamari tends to have slightly lower sodium than koikuchi due to the higher amino acid concentration providing more perceived flavor per unit of salt.

Beneficial Compounds

Antioxidants: Melanoidins (Maillard compounds) have demonstrated antioxidant activity in studies; shoyu contains more antioxidant capacity than red wine per unit volume (though volume consumed is much smaller)
Short peptides: Some fermentation-derived peptides show ACE-inhibitory (blood pressure-lowering) effects in vitro
Isoflavones: Present in trace amounts from soybeans; degraded significantly during fermentation

Allergens

Soy allergen: Present (major allergen)
Wheat allergen: Present in most soy sauces; absent in tamari (check label)
Histamine: Fermented products contain biogenic amines including histamine - relevant for histamine intolerance

“Soy Sauce is Basically MSG” - The Truth

Soy sauce contains large amounts of naturally occurring free glutamic acid - the same ion that makes MSG savory. The umami mechanism is identical. The difference is that soy sauce also contains ~300 other flavor compounds that MSG does not. From a chemistry standpoint, if you’re comfortable eating soy sauce, you’re eating glutamate.

Flavor Chemistry

Soy sauce is one of the most chemically complex condiments - over 300 volatile flavor compounds have been identified.

Umami - Glutamic Acid

The dominant taste driver. Fermentation by proteases breaks soy protein into free amino acids, primarily glutamic acid. This is the same compound as MSG, present naturally in soy sauce at very high levels (~1,000-1,700 mg/100ml). It activates umami receptors and enhances other flavors.

Additional nucleotides (5’-GMP, 5’-IMP) amplify umami synergistically when combined with glutamate - this is why soy sauce paired with fish (high in IMP) or mushrooms (high in GMP) tastes more intensely savory than either alone.

Key Aroma Compounds

Compound	Aroma Contribution
4-HEMF (2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone)	Characteristic “soy sauce” note - caramel-like, meaty
HDMF / Furaneol	Sweet, caramel, fruity
Ethanol	Carries and releases other aroma compounds
Lactic acid	Sourness, freshness, rounds harsh salt
Vanillin	Vanilla, subtle sweetness (from wheat breakdown)
4-ethylguaiacol	Smoky, spicy, clove-like
Isoamyl alcohol	Fruity, banana-like (yeast-derived)
Phenylethyl alcohol	Floral, rose-like (yeast-derived)

4-HEMF is the signature compound - it’s responsible for the unmistakable “smells like soy sauce” recognition. It’s produced by Z. rouxii yeast from sugars during moromi fermentation. Longer fermentation = more 4-HEMF.

Maillard Reactions

Both during fermentation (ambient, slow Maillard) and during pasteurization (rapid), amino acids and reducing sugars react to produce hundreds of brown color compounds (melanoidins) and flavor molecules. This is why pasteurized soy sauce is darker and more flavorful than raw pressed liquid.

Color

The deep brown-red color comes from:

Enzymatic browning during fermentation
Maillard reactions (amino acid + sugar)
Added caramel coloring (in dark/kecap styles)
Oxidation after pressing/opening

Origins and History

China - The Birthplace (~2nd century BCE)

Soy sauce descends from jiang (醬), a broad category of Chinese fermented pastes and condiments dating back at least to the Zhou dynasty (1046-256 BCE). Early jiang was made from meat or fish, but soy-based versions emerged as Buddhism spread vegetarianism across East Asia.

The liquid that pooled on top of fermenting soybean paste was collected separately - this was the earliest precursor to soy sauce, called shi zhi (豉汁) or qing jiang (清醬). By the Han dynasty (206 BCE-220 CE), written records describe it clearly. The name jiang you (醬油, literally “paste oil”) became standard in Chinese.

Japan - Shoyu Diverges (~7th-13th century)

Chinese jiang techniques arrived in Japan via Buddhist monks and diplomats, likely in the 7th century. The Japanese adapted the concept, and over centuries it evolved into shoyu (醤油), which incorporated wheat alongside soybeans - a defining difference from most Chinese styles.

The pivotal development came through miso production. When miso (fermented soybean paste) was pressed, the liquid runoff was collected. In the Kinki region (near Kyoto and Nara), this byproduct was refined into what became tamari (溜まり), literally meaning “that which accumulates/pools.” The oldest records of shoyu as a distinct product appear around the 13th-14th century in the Wakayama and Chiba areas.

By the Edo period (1603-1868), soy sauce production was industrialized. The city of Noda (Chiba prefecture) and Choshi became the centers of large-scale shoyu brewing, supplying Edo (Tokyo). The major brewing family businesses of this era - including Kikkoman (originally Mogi family) - trace their roots here.

Global Spread

17th century: Dutch East India Company (VOC) exported Japanese shoyu to Europe; it became a luxury condiment in royal courts.
Southeast Asia: Chinese migrants brought their methods; local adaptations produced kecap (Indonesia), toyo (Philippines), and others.
19th-20th century: Industrial production enabled global distribution.
Post-WWII: Kikkoman’s 1973 Wisconsin brewery marked the beginning of large-scale Western production.

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