The naturally brewed soy sauce is made with soybeans, salt and wheat. The soybeans are steeped in water for 16 hours; then the soaked beans are dehulled and cooked. The beans mixed with wheat flour or grit are inoculated with fungi Aspergillus orzyae and incubated for three days with occasional stirring. This is called the Koji stage. The resulting material is mixed with brine. A ferment dominated by yeasts and lactic acid bacteria then develops, this being Mormi stage. After an incubation of one month to three years, a dark salty liquid with a pleasant savory aroma is drained from the fermentation vessel, clarified, pasteurized and packaged for sale. Yeast growth is vigorous during incubation period and the production of carbon dioxide indicates that an alcoholic fermentation is taking place. Typically, a full brewed soy sauce will contain between 1 and 2 % (V/V) ethanol. Due to the presence of 2% alcohol, a spirit duty is imposed on naturally brewed soy sauce in United Kingdom.

There are two kind of soy sauce is available in USA and Canada. One is naturally brewed soy sauce supplied by Kikkoman Company with 1.7% or more alcohol and the other is the acidified hydrolyzed soy protein soy sauce (All purpose Seasoning) by ConAgra's Company under LA Choy brand name. The Kikkoman Soy sauce (made with soybean, wheat and salt) is a haram product due to the presence of 1.7% or more alcohol. La Choy soy sauce is a halal soy sauce, which is made with water, hydrolyzed soy protein, corn syrup, caramel color and potassium sorbate with kosher symbol K.

Most Chinese restaurants use naturally brewed soy sauce in cooking the Chinese foods such as vegetable fried rice and also provide it in the bottles on the serving tables. Some Chinese restaurants also supply the soy sauce in small packets with ingredient list and have been found to contain acidified soy protein hydrolyzed soy sauce and not the haram soy sauce.

A Chinese restaurant on Devon Ave. in Chicago made Chinese food with zabiha meat but cooked with --- and supplied for table use--- haram soy sauce from Kikkoman Company.

Muslims are advised to inquire about the use of Kikkoman soy sauce in preparation of Chinese foods such as vegetable fried rice and soy sauce supplied in bottles on serving tables.