(it is held too strongly by the sugar molecules). If ice cream did not contain any sugar, all the water
molecules would crystallise, and the resulting ice cream would be composed of entirely just water
crystals and solid globules of milk fat, which does not give a desired texture to the ice cream. The
liquid that remains unfrozen contains all the sugar, milk fat and milk proteins, and this thick liquid coats
the ice crystals, making them stick together better.
The importance of freezing quickly
Freezing the mixture quickly ensures that a large number of small crystals are formed. If the mixture is
frozen more slowly, fewer larger crystals will form. Ice-cream containing large crystals is undesirable –
it has an icy texture and appears to cut the tongue. Small crystals give ice cream it’s creamy and
The importance of stirring
During freezing, the mixture is stirred. This has various advantages:
a) Stirring incorporates air bubbles which helps disrupt the ice crystal network and makes the final ice
cream lighter and easier to bite into.
b) Stirring ensures that the mixture is cooled in an even fashion, by ensuring even contact of the
mixture with the cool sides of the container in which the ice cream is frozen.
c) Stirring also helps break down any large water crystals that form during freezing, ensuring that only
small crystals form.
Stirring is usually stopped before the end, to allow any remaining water molecules to crystallise onto
already existing crystals – the crystals need to be a certain size to hold the ice cream together.
Storing ice cream
Ice cream should always be stored in the freezer covered. The fat component of the ice cream will
tend to absorb odours from other products in the freezer, and may also go rancid in contact with the
freezer air, if the ice cream is left uncovered, which affects its flavour.
Ice cream is ideally served at 6°C – at this temperature, about half of the water contained will be in its
liquid state. This gives it a desirable texture and makes it easy to eat.