There are two basic kinds of flour: flour for cakes and pastries, and flour for bread. Flour for bread can be wholemeal (brown) or white. In a shop it will always say ‘strong flour’ on the packet. Flour for cakes and pastries is the normal flour you buy in a shop. It may be called ‘plain flour’ or it may be called ‘self-raising flour’.

The difference is in the amount of a substance called gluten, which makes tiny sticky threads when water is added to flour. Bread flour is high in gluten, and this helps it keep its shape during baking. If bread flour is mixed with water, yeast, butter and sugar, it makes dough. Dough ferments in a warm place, producing bubbles of carbon dioxide. These get trapped by the sticky gluten threads and cannot escape, so the dough rises, just like blowing up a balloon. During baking, the gluten loses its stickiness and the bread becomes firm.