How Cold Should a Refrigerator Be?
The short answer is 40 degrees Fahrenheit. The long answer is much more fun. So we will start by talking about freezing semi-solids, then move to refrigeration mechanics, then move on to thermodynamics within the refrigeration space. I promise to leave the math out of it.
If your refrigerator is too cold, the first things to freeze in your refrigerator are the things high in sugar; anything viscous such as jams, berries, etc. You will also see your leafy greens wilt. Damage or ice crystals in these products are your warning sign. Your first course of action should be to turn up the temperature setting in your refrigerator. If you continue to see the problem, it could be a failed thermostat, fan switch, or a problem with how you set up your fridge.
Most refrigerators, commercial or residential, have their internal cooling unit on the top of the unit. This is no coincidence. Heat rises and cold falls so refrigerators are designed with that in mind.
The reason your leafy greens should go in a bin on the bottom is because that is the area furthest from the coldest air coming directly from the coils at the top. The top shelf should be used for the items with the greatest heat load and density such as warm leftovers, liquids, and casseroles.
It is also important to understand the thermostat on a refrigerator usually operates on a differential rather than an exact temperature. In other words, the thermostat will wait until the refrigerator temperature changes 2 - 4 degrees Fahrenheit before initiating or terminating a new cooling cycle. This means that if your temperature is set to 36 degrees Fahrenheit you will likely have freezing temperatures in part of your unit. This can cause frost on the coils that will eventually cause unit failure. So turn up the setting to 40 degrees F.
In addition to considering the proximity to the coils, we must also consider air circulation. All commercial refrigeration units (and most residential units) will have a fan to circulate air from the internal coil around the refrigerator. Air blockages should be considered when loading a refrigerator.
The most common mistake when loading a commercial fridge is to remove all of the shelves and fill it with cardboard boxes full of products. Two problems come into play in this scenario. First, by removing the shelves you have removed the gaps for air to circulate through the unit. Further, all commercial shelves have a stopper in the rear to create a gap for airflow. Do not ignore this simple but important part of a refrigerator's engineering. Second, cardboard is a great insulator, it traps and blocks heat quite effectively. If the product inside the box is not already at the correct temperature do not load it into a refrigerator without at least opening the box.
If you see frost, wilting greens, or your food is spoiling quickly consider all of the above possible culprits. If this does not solve your problem, your unit probably needs maintenance. Call RJH for assistance at 888-937-9080 and our operations manager can help you with further diagnosis or send you a certified refrigeration technician.