Burnt toast

You can’t really eat this experiment but it shows the difference between dextrinisation and caramelisation.

You need

A piece of white bread

A teaspoon of icing sugar mixed with a tiny, tiny amount of water

Either a grill or a blow torch – which is more fun!

A baking tray

What to do

Put the slice of bread on a baking tray and drop a blob of the icing mixture on the middle.

Grill the bread and sugar or burn with a blow torch until the bread changes colour.

Watch the changes in the bread – dextrinisation – and the sugar – caramelisation.

Don’t eat the toast until the caramelised sugar is cool!

The toast should taste slightly sweet – dextrin – and the sugar will taste like toffee.

The science bit

When dry starch is heated – like the flour in bread, a brown substance called dextrin is formed.

The food goes through a chemical reaction where starch breaks down into dextrin which is a slightly sweet, brown substance.

Caramelisation is the process of cooking sugar until it turns brown. All sugars caramelise.

Creme brulee is made by caramelising the top layer of sugar on a custard.