Soy sauce represents a huge customer sector for liquid caramel colors. Discovered in China more than 2,500 years ago, soy sauce is one of the world’s oldest condiments. Its flavor and flavor-enhancing properties make it the base for a variety of other sauces including steak, teriyaki, hoisin, and marinade. There are two distinct types of soy sauces – those that are naturally brewed and those using a non-brew process.
Soybeans and usually an additional grain source (typically wheat) are crushed, soaked, and inoculated with a fungus from the Aspergillus family. Next, the mix is incubated for 3 days, mixed with a brine solution, and fermented with lactic acid bacteria and yeast for 6 to 12 months. This fermentation produces flavor and color. In the U.S.A. the naturally brewed process does not usually use caramel color. However, in many areas of the world, due to economics, the naturally brewed process is shortened. This quicker fermentation reduces color development so soy sauce manufacturers add caramel color to make up for the color loss. In some cases the manufacturer “extends” the fermented soy sauce by adding 15% to 20% saltsolution, caramel color, occasionally molasses for sweetness, and either MSG or I+G to boost the flavor.
This process consists of putting soybeans or another grain source through acid hydrolysis at an elevated temperature for 15 to 20 hours to make hydrolyzed vegetable protein (HVP). The soy sauce manufacturer then neutralizes the liquid and purifies it by filtration. Additional ingredients include salt water (15% to 20% salt concentration), corn syrup or molasses for sweetness, caramel color (about 5% in the case of D.D. Williamson’s Caramel Color #201 depending on the desired color), and sometimes MSG and/or I+G to enhance the flavor.
Left: Red-tone soy sauce diluted in solution.
Right: Low hue soy sauce diluted in solution.
For a caramel color to be applied in soy sauce, there are two major requirements – hue and salt stability. Especially in Asia the redder the caramel’s hue, the better. The caramel colors for soy sauces in Asia need to have stability in 20% salt solution. Caramel colors that are not salt-stable will form a haze in soy sauce followed by a precipitate. While some negatively-charged soft drink type caramels (such as D.D. Williamson Caramel Color #105) are formulated to be salt-stable, because of the high use level of caramel in the soy sauce, sulfites would need to be labeled in those countries requiring it. For caramel color in soy sauce, we recommend the positively-charged, non-sulfited, salt-stable types such as D.D. Williamson’s #201, #203, and #210. These particular caramels also have an appealing red (less gray) tone.