Saccharin

How it's made

Synthesised from petroleum derivatives.

Saccharin is the oldest artificial sweetener, around 300–400 times sweeter than sugar, used in tabletop sweeteners, diet drinks and various sugar-free products. It has a slight bitter or metallic aftertaste at higher levels, so it is often blended with other sweeteners. It provides no calories.

It is made by chemical synthesis from aromatic starting materials. Classic routes begin with toluene or related compounds and build the characteristic sulphur- and nitrogen-containing ring of saccharin through a series of reactions, ending with the free acid, which is then usually converted to a more soluble sodium or calcium salt.

The sweetener is purified and crystallised. Because the body does not metabolise it, saccharin passes through unchanged and adds no energy; despite a historical safety scare that was later overturned, it is now regarded as safe at permitted levels and remains widely used, especially in blends where its intense sweetness stretches other ingredients.