Traditionally, namashoyu is prepared by taking equal quantities of whole soybeans and wheat (roasted and cracked), to which yeast or koji starter is added. Koji is the starter mixture of Aspergillus oryzae or Aspergillus sojae, which is the same starter used in the preparation of the rice wine, amasake. The whole soybeans, roasted cracked wheat and koji mixture are then allowed to rest in warm, humid, aerobic conditions, which allows the microorganisms in the starter to grow. This process takes about 3 days. After the microorganisms are sufficiently grown, it is transferred to giant tanks, and salt and water (brine) are added to it. This mixture now looks like a semisolid mash and is called moromi.

Traditionally, this moromi is then allowed to ferment under natural conditions in giant urns under the sun from 6 months to as long as 3 years. This process converts the mash like mixture into a soft paste like substance when the proteins in the soybeans and starch in the wheat are hydrolyzed to amino acids and sugars respectively. But today, the commercial production of shoyu involves fermentation under mechanically controlled conditions of temperature, and humidity.

Although, the soy sauce is mainly salty, the fermentation process also develops different complex flavors. At the end of this process, a blend of sweet, salty, sour, savory, and umami (Japanese 'fresh taste') is developed. The 'umami' flavor is due to the presence of naturally occurring amino acid, glutamic acid.

During this process, a dark chocolate colored liquid is accumulated on top of the soft mash-like mixture. Different methods are used to collect this liquid 1. Originally, the liquid collected on top of the brewing mixture was ladled off daily. 2. Later, the liquid was removed by pressing a bamboo colander into the center or on the surface of the brewing mixture and the liquid ladled off daily. 3. The soft miso was placed in a cloth sack and the liquid pressed out of it. 4. As improved methods of processing were developed and this is what is mostly used today. The soft slurry miso is poured onto sheets of cheesecloth. Then stacks of this cheesecloth are pressed mechanically under increasing pressure. This process extracted more liquid than the other processes. The liquid thus extracted is filtered, pasteurized and bottled.

Shoyu before pasteurization is called namashoyu (Japanese fresh shoyu).

Commercially blended soy sauce is made by blending hydrolyzed vegetable protein, salt, water flavor, and caramel color. This process only takes a few days, but the flavor of traditionally fermented and commercially blended shoyu is very different. The commercially blended shoyu does not have the complex flavor, fragrance and aroma as that of the traditionally fermented shoyu.

Is it raw?

Namashoyu, traditional or commercial, is not exactly raw but it is all natural as it is processed and fermented. But the traditionally fermented namashoyu is all natural. There are no artificial colors or flavors or fragrances added to it. All the flavor, taste, aroma, and fragrance are developed during the long fermentation process. And as namashoyu is unpasteurized, it also has some live microorganisms that are good for the digestion process.

Buying and Storage:

Select good quality namashoyu from a good brand that is traditionally fermented or brewed instead of blended preparations or keeping the soy beans from 1 to 3 years in concrete barrels. This is generally sold in 1 liter bottles, but also available in larger containers. Look for the label where it mentions 'traditionally fermented' or 'traditionally brewed'. Unopened bottle can be stored at room temperature, but opened bottles should be refrigerated.