cooking with oil

Essential Tips


Tip 1: Get the temperature right

When oil (or fat) is heated to a very high temperature, it becomes more fluid and eventually begins to smoke. Oil should not be taken beyond its smoke point as it spoils its flavour and nutritional value. See our chart for which oil or fat should be used for different culinary tasks.

When deep fat frying, try to use a deep fat frying thermometer. If you don't have one, test it by dropping a 1" (2.54cm) cube of white bread in the oil – it should brown in 60 seconds. If the oil isn’t hot enough, the food will absorb fat and be greasy. Oils that can’t take heat will start to smoke early and burn which spoils the flavour of the food. For deep fat frying the Department of Health recommends oil should ideally be at 350F/175C. Most food cooks rapidly at this temperature and develops a golden colour, crisp texture and good flavour. Refinement of oils extracts any particles and produces clear, neutral oil with hardly any aroma. These refined oils are better for high temperature deep fat frying than cold pressed versions.

Tip 2: Be safe

Watch out for the flash point. Don't heat your oil too high as it can catch fire! After the smoke point, if you keep heating the oil, at some point you’ll get to the flash point, where tiny wisps of flame start to burn. Shortly after this the oil will catch fire. If it does, remove the heat source if you can do so safely. Do not throw water on burning oil or it will be violently displaced from the pan and burn whatever is around it. Instead, smother it with a tight fitting lid or use a special fire blanket or a damp tea towel to cut off the oxygen to the flames. If the oil has spread suffocate it with baking soda or a fire extinguisher formulated for oil fires

Tip 3: Best results

Make sure that the food you're going to fry is dry. Letting it sit on paper towels, or coating it in flour or bread-crumbs is a good way to ensure this. Let the coated food sit on a wire rack for 20-30 minutes so the coating dries and sets. Don't overcrowd the pan! Carefully add the food, leaving lots of space around each piece, so the food will cook evenly. If you add too much food at once, the oil temperature will drop and the food will absorb oil.

Watch the food carefully as it cooks, regulating the heat if necessary to keep oil temperature consistent with the method. When the food is browned according to the time in the recipe, it's done. Remove it with a slotted spoon or a heavy stainless steel sieve with a long handle. Drop it onto paper towels to drain.

Tip 4: Look after your oil

The Department of Health recommends deep fat frying oil is changed before it foams, froths or smokes. You’ll know its time to renew your oil when it changes colour or smells rancid or fishy when you heat it. This will depend on what temperature it has been heated to and what has been cooked in it. Try not to heat your oil above 350F/175C. After use, strain all the food particles out of the oil and throw them away. Once cool cover tightly, and seal it before you use it again.

If you fry foods like sausages, chicken and anything in breadcrumbs, don't fry these in the same oil you are using to fry chips as they will affect your oil quality.

Tip 5: Use liquid oil

The Department of Health recommends using low saturated fats for frying tasks, as the more saturated fat in your oil, the more saturated fat there will be in your finished dish. Liquid oils such as rapeseed and sunflower have about 10% saturated fat, where as some fats like beef dripping have about 50%. Whichever oil you use, make sure it’s not hydrogenated.

Tip 6: Storing oil

All oils turn rancid in time and most oils are best consumed within the year of their production. Refined oils can be stored for longer than unrefined oils like virgin and extra virgin and cold pressed oils. These unrefined oils carry the true bouquet, taste and nutrients of whatever is their source ingredient. However they are more prone to oxidation when opened and exposed to air and so go rancid more quickly. Look at labels to see when you should discard cooking oils. Cool oils to 140F/60C before returning to bottle. Always store oils in a cool dark place, out of direct sunlight and away from any heat source.

Tip 7: Disposing of oil

The Department of Health recommends discarding cooking oil before it becomes dis-coloured, froths, foams, begins to smell or once it has been heated beyond its smoke point. Ideally, try to change it between 2-3 uses as prolonged consumption of repeatedly heated oil has been shown to generate trans-fat compounds. After used oil has cooled, discard it safely. Never pour used oil down the drains. Once it is cooled dispense it into a container and seal it up. You can either recycle it for use as biodiesel or dispose of it in your household waste.