Why is beef fat a solid at room temperature?

The primary factor that determines whether a fat is solid or liquid at room temperature is its fatty acid composition. Beef fat is predominantly composed of saturated fatty acids, which have a higher melting point compared to unsaturated fatty acids. Saturated fatty acids have a higher proportion of hydrogen atoms compared to carbon atoms, resulting in a more compact molecular structure. This compact structure allows for stronger intermolecular forces, such as van der Waals forces, between the fatty acid chains, leading to a higher melting point.

In contrast, unsaturated fatty acids have double bonds between carbon atoms, creating a kink in the molecular chain. This kink disrupts the close packing of the fatty acid chains, weakening the intermolecular forces and lowering the melting point.

Therefore, the high content of saturated fatty acids in beef fat causes it to have a higher melting point, resulting in its solid state at room temperature.