Me and my girlfriend have been having a discussion for a whole day about whether or not fats are oils. We’ve googled it and the only facts we found is that fats are solids and oils are liquid, we also found that they are the same, we both agreed on that. But she also claims that oils are necessarily plant-based, which I don’t agree with.
She’s studying biology, and knows the chemistry and the proper names for things, while I have less scientific know-how, but know damn well you can use bacon fat as cooking oil. I don’t know if l’m right, moreover, I don’t know how to explain that she is wrong (if she is). Please help.
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Oils are fats that are liquid at room temperature. That being said, coconut oil and palm kernel oils are solid at room temp because they have high amounts of saturated fatty acids.
Oils are not only plant-based, there are fish oils for example, but bacon grease is fat.. not oil.
All fats can go into one of two categories. Saturated, and unsaturated fats. In general, saturated fats tend to be solid at room temperature (like butter), while unsaturated fats (like olive oil) tend to be liquid.
The “why” gets into details about chemical structure, so it is a bit of a jump.
All fats have long carbon chains, essentially with one carbon atom attaching to both the previous and next one. Some of them have those carbons atoms always having 2 hydrogen atoms attached as well. Those are *saturated* fats (there’s no more room for hydrogen to jump in). Some don’t have hydrogen in every spot, but have double electron bonds between carbon atoms instead. These are unsaturated fats. They’re generally considered the healthier fat because this gives them more space to interact chemically and have some beneficial effects.
Those double carbon bonds result in the shape of the molecules being very different, and the tl;dr is that unsaturated fats can’t really “settle” into a nice structure as a result of their shape, while saturated fats can. Of course, add enough heat or take away enough heat and that changes for everything, but it just so happens that room temperature tends to have solid saturated fats and liquid unsaturated fats.
It’s interesting how different perspectives can lead to such debates! While it’s true that fats can be solid and oils are typically liquid, oils can be derived from both plant and animal sources, just like bacon fat
So, you’re both partially correct in your understanding.
The general structure is called a “triglyceride” and if the specific structure is a solid at room temp it’s a fat and if it’s a liquid at room temp it’s an oil.
It happens that animal triglycerides are usually solid (animal fat) and plant triglycerides are usually liquid (vegetable oil).
Fish oils though are animal triglycerides that are liquid at room temp.
>But she also claims that oils are necessarily plant-based
No.
Chemically speaking, “oil” just means “anything non-polar that’s mostly hydrocarbons”.
Culinarily speaking, it’s just that most vegetable fats happen to be liquid at room temperature and are called “oils” while animal fats tend to be solid at room temperature and are called “fats”, but chemically it’s all the same..
Yes. It has to do with polarity. A water molecule is electrically polar, it has a positive side an a negative side. Oils/fats are non-polar, they don’t really have a concentrated charge anywhere. That’s why you can’t dissolve oil in water and vice versa and that’s where we draw the line in chemistry.
To answer the plant-based question. An example of an animal based oil is sperm whale oil, which was considered one of the finest possible lubricants before synthetic petroleum based oils were invented. It’s now banned because – well, we nearly ran out of sperm whales.
“says oils are only plant based” well I guess fish oil, whale oil, and the oil that makes your face oily are all fake then.
[Whale oil](https://en.wikipedia.org/wiki/Whale_oil) didn’t come from plants. One kind of whale oil was used for oiling very precise instruments, like pocket watches. As whales became endangered, there was a search for a replacement oil. Jojoba plants made a very good [substitute for whale oil](https://www.sciencenews.org/article/50-years-ago-jojoba-desert-shrub-help-save-endangered-whales). It just shows how close oils from plants and animals can be.
So, fats and oils are both “triglycerides”, which is to say, they both have three big floppy chains of carbon atoms each connected to a glycerol molecule.
The big difference is that animal “fats” typically have a structure in the big floppy carbon chains that causes them to have a higher melting point than vegetable “oils”. So, “fat” triglycerides are usually sold at room temp, and “oil” triglycerides are usually liquid at room temp.
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