Blast chillers or freezers operate by blowing forced cooled air over food placed inside. These specialized freezers usually have various settings that can be selected depending on if your food is room temperature, chilled, or hot. This rapid cooling process decreases the number of ice crystals that appear on food.A typical blast freezer temperature hangs between -30 to -40°C. This is far colder than regular freezers, which tend to keep food at around 0°C. The big temperature difference means a blast freezer can freeze food effectively in under 3 hours. Where it might take anywhere from 6-12 hours in a normal freezer.