How cold should your fridge be? How often does it need to be emptied? And is it safe to keep open tins of food in it? Here is a guide to keeping it cool

With a smile and a bin liner, Marie Kondo is about to descend on your fridge. An Instagram story from her lifestyle brand KonMari.com yesterday ruled that you should always keep your fridge 30% empty – or 70% full, if that means more to you – for shopping and leftovers. The appliance they illustrated the rule with was so comically clean and colour-coordinated, you wonder who can live – and shop and cook and clean – like that.

But from a purely technical perspective, uncluttering your fridge has undeniable benefits: it ensures the air can circulate freely, meaning the temperature stays steady and the appliance lasts longer. And it allows you to stay on top of your provisions: you’re more likely to use them up in a timely manner and not buy more of what you’ve already got. Lastly, and a big part of Kondo’s enduring appeal, is a clean, tidy, pretty fridge is absurdly calming. I have long hung washing and stacked bookshelves by colour for that reason – why not chilled produce, too?

So, to break the dream down into more manageable parts, here is a guide to fridge hygiene.

1) What is the optimal temperature?

Between 1C and 4C: you want your food to be kept at 5C or lower. Go for colder when your fridge is full or you’ve just packed it with a big shop on a hot day; to save on energy, a little warmer when it is cold and your fridge is looking a little bare. (NB: Defrost your freezer when ice is more than 5mm thick – about once a year – but don’t allow any in your fridge as it prevents air circulation and messes with the appliance’s inner thermostat.)

2) How often should you clean it, and with what?

Clear up spillages immediately. Wipe down the handles daily and, once a week, the door outside. Check shelves and containers for anything lacklustre or out of date – and bin. Once every three months, empty the whole thing, take out all removable parts (shelves, drawers, racks) and wash with hot water and a little washing-up liquid (never bleach or any non-foodsafe chemical cleaners).

Facebook Twitter Pinterest Don’t keep open tins of food in the fridge – decant the contents. Photograph: Alamy

3) And if you need to deep clean?

Use a toothbrush and a thick paste of bicarb mixed with water to get rid of stubborn stains. At this stage the Spruce recommends unplugging your empty, clean fridge and hoovering – hoovering! – underneath and behind it, as well as removing any vented covers to reach dust-coated fans and coils. The reason (the dust makes the fridge work harder) might be sound, but that remains a level of domestic proficiency with which I am decidedly unfamiliar.

4) What should not be in there?

Most fruit (including tomatoes and cucumbers) should be kept at room temperature and out of the sun – especially any that need to ripen; farm eggs you’ve bought at room temperature; and a lot of veg (potatoes, carrots, onions, garlic, winter squashes, beets, and other roots, including ginger).

Don’t store opened tin cans – once open to the air, the tin from the can can transfer more quickly to the can’s contents. Only cans that come with resealable lids are fine to keep in the fridge. Decant leftovers (see below).

Don’t refrigerate hot food: wait for it to cool completely, to avoid contamination and messing up your fridge temperature. Products past their “use-by” date or not finished within the “once opened” timeframe belong in the bin. Finally, bread: Serious Eats once published a 1,164-word article detailing why refrigeration ruins bread; read it, or if life’s too short, just trust me.

5) And what should?

Ripened fruit, citrus, all berries, milk, yoghurt, meat, fish, any opened product that specifies refrigerating once opened. Eggs need consistent temperatures, so if you’ve bought them refrigerated, keep them that way. All veg apart from those above. Leftovers (as soon as they have cooled), and any fresh, ready-to-eat, deli-style products. Large tubs of nut butters that you won’t use up quickly – the cold should keep them from separating. Open pickles and jams can be kept in a cool dark cupboard, as can mustard, syrup, but read the instructions on the jar. Opened wine – even red – should go in the fridge.

6) What goes where?

Top shelf: anything that doesn’t need cooking (sliced meats, dips, leftovers, deli dishes, tortilla wraps etc), as well as the contents of any unfinished tin can, decanted into a clean, lidded container.

Middle shelf: all dairy and eggs – despite the milk bottle-specific door racks, and door egg-holders, doors are not the right place for either.

Bottom shelf: meat and fish.

Veg drawers: fruit, veg, leaves, herbs. Lettuce and other greens (washed, thoroughly dried, wrapped in paper towel) go in a spinner, their own container or a veg drawer all to themselves. Store all soft fresh herbs (except basil) like a bouquet, washed and in a glass jar with a little water, well away from the icy back of the fridge.

Door racks: juices, condiments, spreads etc – things with the longest shelf-life.

7) Store together or always separate?

The rule of thumb is to store like with like: meat with meat and fish with fish; veg and fruit in separate veg drawers (mixing the two often results in the ethylene the fruit produces spoiling the veg); herbs and green leaves away from the icy-cold back of the fridge (to which they’ll inevitably stick, thereby making a mess of both your fridge and your salad plans.)

Facebook Twitter Pinterest Keep an open box of bicarbonate in the bottom to deal with odours. Photograph: Forest S/Alamy Stock Photo

8) Tips for shelf organisation

Adjust your shelves, and stack wisely: use flat long containers (juice carton-length) to make use of the full depth of your fridge; use lidded containers that can stack in order of height; put tall things behind short ones (so nothing is hidden); and position duplicates (bottles of beer, say) one directly behind the other. Glass is best for visibility, hygiene and sustainability: get containers with lids that shut tight. Label anything opened or decanted with the date of purchase: washi tape is undeniably good-looking, but any plain tape you can write on works too.

9) Tips for dealing with odours

A well-sealed glass container is best. Also, keep an open box of bicarb on the bottom shelf – or sprinkle some at the bottom of your veg drawer and cover it with paper towel. (Of course, when you replace the bicarb every three months, don’t bake with it. Use it instead to scrub your bathtub, or empty it down the loo with some malt vinegar for a good clean.)

10) Tips for dealing with fridgemates (AKA how to word the passive-aggressive note)

Talk before you stack. Food website The Kitchn recommends keeping shared fridges as symmetrical as the hardware allows, so if there are two of you, divvy the lot down the middle, and make sure you both know what is communal (the door?). Abide by the above rules for your own stuff and put anything special in an opaque bag to make it obviously not for common consumption. But if communication does break down, or wasn’t happening in the first place, take your cue from the now legendary cheese-slice war between rowing Australian office workers, grab a Sharpie and a Post-it – and then tweet about it.