Ice Cream
Practical Action
The two main factors that affect the texture of the ice cream are:
1. the incorporation of air (overrun), which increases the softness and lightness of the
product and allows it to be easily scooped; and
2. the rate of freezing which affects the size of the ice crystals.
Commercially made ice creams usually have a smooth, soft texture, due in part to faster freezing
which produces smaller ice crystals. The smaller the ice crystals, the less detectable they are by
the tongue. They also need less heat to melt in the mouth and as a result the ice cream does not
feel excessively cold when eaten. Slow freezing creates larger ice crystals that give the product a
gritty texture, and it may also feel too cold when eaten. Other ingredients, including proteins
from the dairy ingredients and added emulsifiers, stabilise both the air bubbles and the
emulsion to give a smooth texture.
Packaging and storage control
The ice cream should be stored in a freezer at -18°C. It should not be allowed to melt for two
reasons: first this would allow any bacteria in the ice cream to grow and spoil the product, and
secondly the air in the ice cream escapes and it loses its texture to become solid ice when re-
frozen. When ice cream is warmed (e.g. by opening a freezer door) some of the ice crystals
nearest to the warm air partially melt and then refreeze when the temperature drops again. This
causes the ice crystals to grow and the ice cream to taste more ‘gritty’. Therefore producers
should advise retailers to minimise the number of times and the duration that ice cream freezers
are opened. There should also be rapid stock turnover to prevent the development of grittiness in
the products. Ice cream requires protection against dust and insect contamination during
distribution and retail display. Plastic pots are most commonly used, sealed with a foil cover or
clip-on plastic lid. Other alternatives are waxed paperboard cartons or cups.
Summary
Ice cream is high-risk product that has the potential to cause food poisoning, but with care it
can be made successfully at a small scale. It may have a high demand in urban areas and a
wide range of products can be made with different flavours, textures and colours, provided that
suitable ingredients are available and the required skills and experience exist in the dairy.
Equipment required
Pasteurising pan preferably made from stainless steel, but aluminium is acceptable (see
Technical Brief: Pasteurised Milk).
Thermometer (-30 to 100oC) for checking product and freezer temperatures (preferably
an electronic thermometer).
Ice cream maker
Freezer or frozen storeroom
Scales (e.g. 0-10 kg +/- 2 g for weighing ingredients).
Optional
Pot sealer. Pot sealers can be made locally by fixing a domestic electric iron to a drill
stand. Commercially available pot sealers have a thermostatically controlled sealing
head, which can be adjusted for sealing foil or plastic lids.
Equipment suppliers
Note: This is a selective list of suppliers and does not imply endorsement by Practical Action.
The website www.smalldairy.com/dairy%20resources.html also lists equipment suppliers,
laboratory supplies, books and contacts for small dairy processing.
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