Soy Sauce and Caramel Color

Caramel Colour in Soy Sauce

Soy sauce represents a huge customer sector for liquid caramel colours. 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.

Naturally Brewed

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 colour. In the U.S.A. the naturally brewed process does not usually use caramel colour. However, in many areas of the world, due to economics, the naturally brewed process is shortened. This quicker fermentation reduces colour development so soy sauce manufacturers add caramel colour to make up for the colour loss. In some cases the manufacturer “extends” the fermented soy sauce by adding 15% to 20% saltsolution, caramel colour, 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 colour (about 5% in the case of D.D. Williamson’s Caramel Colour #201 depending on the desired colour), 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.

Selecting the Right Caramel Colour

For a caramel colour 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 colours for soy sauces in Asia need to have stability in 20% salt solution. Caramel colours 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 Colour #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 colour 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.