Some fridges have a chiller, which may have its own temperature control. This is in fact just a baffle (an adjustable flap), not a thermostat: adjusting it to allow more cold air in will decrease the temperature. A chiller is good for storing fresh meat at around 0°C, keeping it safer to eat for longer than if stored in the main fridge compartment.
To check whether your fridge is cooling as it should, buy a food or fridge thermometer (from a kitchen or catering supply shop, hardware or electrical store) — or one for each compartment — and monitor temperatures in the fresh-food and freezer compartments. A fridge should be able to achieve –18ºC and 3ºC simultaneously in the freezer and fresh-food compartments respectively in cool to warm environments. If your fridge has problems reaching or maintaining these temperatures, contact the manufacturer.
Conventional controls — thermostat and baffle
Many conventional fridges have two controls, but that doesn't mean one controls the freezer and the other the fresh-food compartment. Though you'll often find one control in each compartment, adjusting either of them can in fact affect the temperature in both. This is because one of the controls is usually a thermostat, while the other's a baffle.
- The thermostat senses the temperature (sometimes in the freezer, sometimes in the fresh-food compartment, and sometimes in both — it varies from model to model) and, if it gets too warm, the compressor (the motor unit) kicks in, producing cool air. When the temperature is right, the compressor turns off.
- The baffle control dictates how much of the cold air is directed to the freezer, and how much to the fresh-food compartment, and so dictates the relative temperatures of the two compartments.
So how do you know which is which?
Ideally they'd be properly labelled, perhaps as 'Temperature' and 'Balance control'. Often, though, they're both just labelled 'Temperature control', giving the false impression that the temperatures in the fresh-food compartment and freezer are independent.
Check the instruction manual that comes with your fridge — the better ones do explain which control does what, and it's worth reading it carefully to get your fridge's performance right.
Alternatively, when the compressor is running try turning one of the controls to the warmest setting — if it's the thermostat control it will turn off the compressor. If it doesn't, it's the baffle.
If you still can't tell, call the manufacturer for the information.
Electronic fridges — better control
Some — though not all — electronic fridges use a different system, which can be much easier to use. These fridges have separate controls, sensors and fans, allowing the temperatures selected for the two compartments to be relatively independent.
Should I alter the settings?
When I've put in fresh groceries?
Once you've got your fridge temperatures right, you shouldn't need to fiddle with the settings to cope with a load of warm groceries. If a fridge does its job properly, turning the temperature control to colder when you put a large load in won't speed up the cooling process — it'll just mean your food ends up colder.
If your fridge doesn’t seem to react to a warm load by starting the compressor running to cool it down, you can try setting it colder for a while, but don’t let the food get too cold before turning it back. Alternatively, have it checked by a service person — or, if it’s old, consider buying a new fridge.
From summer to winter and vice versa?
You may find your freezer gets warmer — not colder as you might expect — during the winter months. It's a good idea to keep an eye on temperatures using a fridge/freezer thermometer — or two — particularly in the height of winter and summer.
- Opening the fridge door means lots of cold air can escape. By keeping your fridge moderately full, you'll help prevent the fridge from warming up too much (and reduce any food safety risks). This also keeps the temperatures more even throughout the compartments.
- It's often difficult to get both the fresh-food compartment and the freezer at the right temperatures. Buy two good thermometers — one for the freezer and the other for the fresh-food compartment to help you get the temperatures right. Go to our Fridge/freezer thermometers article for which ones to buy.
Which foods should you put where?
The crisper The enclosed drawer(s) you’ll find at the bottom of most fresh-food compartments — is designed for keeping fruit and vegetables fresh. A good crisper should be cool and well sealed, which means it won’t be as dry as the rest of the fridge, so your vegies should stay fresh for longer. Check that the fridge's air outlets don't blow into it, as this will dry them out faster.
The door shelves are usually the most convenient spot to put bottles, whether of milk, soft drink, sauce, juice or wine. But in some of the fridges we’ve tested, the door bottle shelves have been warmer than is ideal for keeping milk (it’s best stored at or below 4°C). If you want it to last longer, keep it in a colder place in the body of the fridge. And some fridges’ door shelves are too small to store soft-drink bottles.
Dairy compartment This is intended to keep cheese, butter and the like at a warmer temperature than in the rest of the fridge — closer to serving or spreading temperature. Of course, cheese in particular won’t last as long as if it’s stored at a colder temperature. Soft cheeses shouldn't be stored here but in the cooler main part of the fridge, because they're prone to contamination with listeria bacteria. You may also have a butter conditioner, which has a small heater to keep butter soft and spreadable. The heater may have a few settings, ‘hard’ usually means the heater’s off and the conditioner functions as a dairy compartment.
Chiller compartment Some fridges have a chiller compartment, which should be at around 0°C to keep perishable food fresh for longer. It's useful for keeping uncooked chicken, fish and other meats fresh, or even for quickly chilling a drink. You’ll also find that precooked foods keep longer here, but be careful about cross-contamination with raw foods.
Convertible compartments A few fridges have a versatile compartment that you can use as a chiller or crisper by selecting the right temperature. Some also have a warm setting that’s ideal for storing tropical fruits, tomatoes and so on.
Egg storage Store them in the fridge in their original carton: it protects them, slows down moisture loss, prevents them absorbing odours from other foods and enables you to keep track of how old they are. Fresh eggs should keep well for four to five weeks; boiled eggs in their shells will keep for up to five days. Cracked eggs may be contaminated, so throw them out.
Freezer compartment As with the main compartment, it’s best to avoid loading too much in at once, and don't put piping hot food straight into the freezer, as it’ll warm up the food that’s already there. If your freezer’s relatively full, its temperature’s more likely to stay even and your food should last longer. However, be careful not to block the cold-air outlets with a frost-free model, and leave air space around the walls for better air circulation.
For best temperatures and storage conditions for fruit and veges - CSIRO