The 0°C (32°F) notch on a refrigeration unit’s thermometer marks the numerical difference between freezer rooms and coolrooms. However, ideal temperatures don’t adhere to such absolutes. In lieu of a categorical crossover point, the scientifically measured temperature at which water turns to ice, we refer to standard cooling envelopes. In cold rooms (Also known as coolrooms or cool rooms), that thermal envelope keeps food unfrozen but safe.
The Ideal Food Safe Temperature Range
The thermostat in the cool storage room adjusts between 1°C and 10°C. Some of these walk-in units advertise a 0°C lower limit, but this feature is rarely used because it’s crossing over into a territory that’s reserved for freezers. Instead, the higher limit is typically locked in at 5°C while that important lower limit sits firmly at 1°C. Set any lower, well, the carbonated beverages and fresh fruits would turn to a fruit-flavoured icy slush. Arguably, a rise of temperature represents a greater hazard, with the foodstuff spoiling and rotting as the sealed chamber warms.
Temperature Boundaries: Walk-In Freezers
The safe holding temperatures used by walk-in coolrooms are important if food freshness is to be maintained. Walk-in freezers take this concept and drive it down lower, to the point water turns to ice. Even then, the negative thermal envelope drops further. We’re referring to an arctic domain that straddles the 0°C to -23°C temperature spread. Granted, the zero celsius storage point does turn the water inside the food to ice, but certain biological processes may not b
e arrested by that icy membrane. In other words, the colder the frozen food becomes, the longer it will retain its fresh taste. Down at that lower boundary, bacteria stops growing, enzymes are frozen, and nutrients are locked inside soft tissues.
A refrigeration unit that’s designed to freeze water is built with a more powerful set of coils and operational parts. Similarly, the sealed enclosure will address some issues that are uniquely connected to subzero issues, including the incorporated defrost cycle. The insulation panels will be thicker, the water drainage system more capable, and the intake ducting will be sized to draw in larger volumes of air. Of course, those two ideal operating conditions also take aim at different stored commodities.
Raw cuts of meat and frozen foods are stored for long periods in 0°C to -23°C walk-in freezers. Above freezing point, beer, soda, and fresh produce are held between 1°C and 5°C, so they’re cool and fresh and ready for safe consumption. Additionally, freshly prepped meats and meals are stored in some coolrooms, but only if they’re being used that night.