Green S
What it does
Green colour.
How it's made
Synthetic dye.
Green S is a synthetic green colour used in products such as mint sweets, sauces, peas and desserts, giving a strong, slightly blue-green shade on its own without needing to blend a blue with a yellow.
It is a triarylmethane dye made by chemical synthesis from aromatic starting materials. The manufacturing builds the characteristic three-ring central structure and adds sulphonic-acid groups for water-solubility, with the particular substituents tuned to give the green colour.
The dye is purified and standardised, with limits on impurities, and supplied as a dark green to blue-black powder that dissolves to a green solution. Its use is set out in colour regulations, and it is chosen where a ready-made green is more convenient than mixing separate colours.
Possible reactions
Possible intolerance in sensitive individuals.