The damaged fat droplets and fat crystals form a network that traps within it the water droplets and the
free fat molecules that have leaked form the damaged droplets. This is what gives butter its relatively
solid structure. As well as a large amount of fat and some water, butter contains, in smaller quantities,
proteins, carbohydrates, and minerals, all evenly distributed through its structure.
Butter is fairly fragile – exposure to air and bright light means the fat molecules break down and
decompose into small fragments.
Also, butter has the tendency to absorb strong hydrophobic odours from its surroundings, due to its
elevated fat content. It should therefore be kept in a sealed container in the fridge.
Cooking with butter
Butter contains over 500 different types of fatty acids. Each different triglyceride will melt at a specific
temperature, depending on its structure.
Therefore, because butter is made up of a large range of different triglycerides that melt at different
temperatures, butter does not melt at a fixed temperature like a pure solid like ice. Butter triglycerides
melt over the range – 10°C to 40°C. At room temperature, the majority of the fats are in their solid or
crystalline form, so the butter is solid. As butter is heated, the fats that are in crystal form will melt and
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liquefy - if butter is heated up to 40°C, none of the fats will be in their crystal form, and all liquid
contained is no longer trapped by the fat crystal network, and the butter will be entirely liquid.
The many different triglycerides found in butter can be grouped into three main classes depending on
their melting temperature:
The triglycerides that melt at temperatures between – 10°C and + 10 °C, are the short and very
The triglycerides that melt between 10°C and 20 °C are the slightly longer and slightly less
The triglycerides that melt between 20°C and 40 °C are the saturated triglycerides, which melt at the