Learn more about fat, how we use it in cooking – and why you should know about the ‘smoke point’.
After reading this article, I am sure you will agree that fats are a fundamental part of your cooking, both because they taste great and serve a practical purpose.
Here are some tips on choosing the right fat for the right task in the kitchen – and you'll get a clear understanding of what the ‘smoke point’ actually means for cooking.
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Why do we fry with fat?
While water evaporates at high temperatures, fat can withstand higher temperatures – and this is precisely how we achieve that delicious crust when frying.
Fat is water-repellent, acting as a lubricating layer between the pan and whatever you are frying. It is the protein content in meat and vegetables that normally causes food to stick.
With a little oil, you can avoid eggs sticking, and the right fat can act as a fantastic flavour enhancer.
What is a ‘smoke point’?
Fat can withstand high temperatures compared to water. However, there is a limit which, when exceeded, can cause the oil to burn.
This is the ‘smoke point’.
Oils, lard and butter withstand heat differently, so it is important to know what temperatures your frying pan or oven should be at to complement the properties of the fat. Regardless of the recipe, you should choose your fat and cooking temperature with this knowledge in mind.
Brief overview of fats and their smoke points:
Clarified butter: 250°C
Refined olive oil: 240°C
Refined sunflower oil and corn oil: 232°C
Grape seed oil and virgin olive oil: 216°C
Refined rapeseed oil: 204°C
Butter, extra virgin olive oil & coconut oil: 160-180°C
Note that the more processed, refined and therefore ‘neutral’ the ingredient is, the better it can withstand heat. This is due to the processing. Unrefined and cold-pressed fats still have their natural minerals and enzymes intact, which give them a fantastic flavour – but not particularly good heat tolerance. This is typically the case with the olive oil that many people have in their cupboards – it tastes and smells fantastic, but is actually not very good for frying.
So, in short: stick to flavourful unrefined oils at lower temperatures – e.g. in a salad. And use clarified butter or refined oil for browning and when you want to create the perfect roast crust.
Note: regular butter does not have the same high heat tolerance as clarified butter. Therefore, you should never use regular butter at very high frying temperatures, as it will burn – instead, use butter when frying at lower temperatures or add a good knob of butter to your steak shortly before it is done and use the butter (perhaps with a few sprigs of thyme and a clove of garlic) to add flavour.
How to use your knowledge of the smoke point for carbon steel and cast iron frying pans
Oil is absolutely essential when you have a carbon steel or cast iron frying pan.
This is because the pan needs to be seasoned, and a natural non-stick coating will form when the oil is cured on the surface of the pan.
You can use your knowledge of the smoke point of oil when treating your frying pan. Here, you should actually go for a refined product with a high smoke point, such as grape seed oil.
A more unrefined product such as extra virgin olive oil, which many people have in their kitchens, will give a sticky result when you season your frying pan – this is due to both the low smoke point and the high content of natural minerals and aromatic substances.
The hardening process with the oil is due to a chemical process – polymerisation – where the fatty acid chains combine to form long polymers. In short, this means that the many fat molecules are bound together by oxygen at high temperatures, which means that it is no longer liquid but instead forms a hard, water-repellent surface.
Polymerisation occurs just around the smoke point, so when treating our carbon steel pan with grape seed oil, we just need to make sure to do so at a temperature above 216°C.
Read more about how to treat your carbon steel frying pan with oil.
Enjoy cooking!
