Everything you wanted to know about cooking oil – how to store it and what to do with it when it gets old

We all love crispy deep-fried foods like chips and calamari, but what to do with the leftover oil? It’s a problem I often have in my own kitchen, so I chatted with Tersia Joubert, Research and Development Technologist from BeWell Foods. Here’s everything you wanted to know about old cooking oil – how many times to use it, how to store it and where to put it when you’re done with it.

How many times can I use my cooking oil? 

Usually, you can re-use your oil at least three or four times. This is encouraged as you will save money and assist the environment in reducing sewer blockages. For those who fry often, one needs to consider the type of food being fried, the frying conditions and the temperature at which the frying takes place.

RECIPE: Crispy tofu with spring onions and mung beans tossed in peri-peri sauce

How do I know when it is old/no good? 

It’s best to keep an eye on your oil – the moment you start seeing the oil give off a thick, gummy consistency and it becomes much darker in colour are clear indications to stop using this oil. This means that the oil molecules have started to join together into much bigger molecules, which gives off the thick gummy consistency.

What is the best way to store it? 

What works best for me is to filter the oil once cooled and place in a resealable plastic container. It is important to place it in a container that has limited headspace. If there is little to no oil being stored and too much space available within the container, it will speed up the oxidation process. Therefore, ensure you store enough oil in a cool, dry area. I would place the container in the refrigerator if you have space. The oil might become cloudy, but this will change once its heated. Always ensure you label your oil and know what it was last used for.

RECIPE: Veggie fritters with a coconut dipping sauce

Do’s and don’ts when disposing of old oil: 

DO:

• allow solidified fats (such as bacon fat) to harden in the pan and then scrape into the bin
• pour oils into a non-recyclable, resealable container (such as a glass jar) and throw the container in the bin
• dispose of oil in a plastic bag that has other waste in it – be sure to tie it tightly closed

• search for recycling companies in your area if you have a large amount of oil to dispose of
• compost oils that are safe for composting – do this in small quantities. Add no more than half a cup of vegetable oil to your compost heap each month, and then monitor your heap.
• reuse your oil if it has been stored in a resealable plastic container and carefully sieved to remove any particles

RECIPE: Crispy amasi fried chicken

DON’T:

• pour any fats into the toilet
• pour any fats directly down the drain
• use any oil that was used to cook meat or animal products as compost as it is unsafe and can attract rodents or unwanted pests to your garden – note, however, that large quantities of vegetable oil in your compost will reduce airflow and prevent necessary water from spreading
• pour oil on its own into a shopping bag and into the bin – this will leak

Cooking oil FAQs

Can oil go in the garden/compost? Yes, but only vegetable oil in small quantities, not oil used to cook meat.

Can oil go in the rubbish bin?  Yes, either in a reusable container and placed directly in the bin OR placed in a shopping bag along with other items such as toilet roll or kitchen paper, which will absorb the oils.

Can oil be used for cleaning? I would not recommend using oils to clean areas within the house, especially the kitchen as it can easily clog the drain in your sink.