Description : Butter has a natural pale-yellow color, but butter can also turn brown in the freezer due to the Maillard reaction (a non-enzymatic browning process in butter). This reaction occurs when the milk solids in butter turn brown. The milk solids have a lower smoke point than the fat in butter. Also, Butter can turn brown in the freezer due to oxidation. When butter reaches a certain temperature, it reacts with oxygen in the air. Tehatta, West Bengal; India.