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When rendering beef fat, there may be a point during which you wonder whether it will all work out. Will that gooey, octopus-like mass truly turn into pure liquid fat?
Be patient. If done well, the previously hard, unappetizing pieces of fat, will turn into liquid gold. It’s a matter of slowly, but steadily, breaking up fat cells and evaporating moisture.
- Rendering fats prevents waste
- What happens when rendering beef fat
- What is beef tallow made of?
Rendering fats prevents waste
Only about 50% of the weight of a cow grown for meat consumption is made up of edible meat cuts. The remainder of the cow, such as bones, hides, and fat can’t be sold as a piece of meat. But, that doesn’t mean there is no longer any value in these products. It would be a waste to throw these out. It’s why most of them are re-used in some way, they are ‘rendered’ by specially dedicated meat rendering facilities.
If you’re not a butcher you can’t necessarily re-use these parts. You might not get the bones or the hides. But, if you do get meat with excessive fat, there is a way you can contribute to minimizing waste: render that fat and use it for a range of other applications.
That’s what we did when we prepared a large piece of brisket. Almost 20% of that piece of meat was made up of fat that we had to slice off on forehand, as well as some trimmings. We used the meat trimmings as the basis for a stock and rendered down the fat.
What is fat rendering?
In the meat industry, rendering is used to refer to just about any process that turns animal by-products into usable products. Some of them may be edible, others may be used in other industries.
For home cooks and chefs though, the term rendering refers to one specific process that focuses on melting down, solid fats, into fats that you can use in other applications. The fat may come from beef, pork, chicken, or just about any other type of animal. Here, we’ll focus on rendering down beef fat.
Why render beef fat?
Cuts of beef may contain large pieces of fat, and so does a carcass as a whole. A cow stores fat as an energy reserve. The fat is stored in fat cells, in specific areas within the body. The cells hold the fat together and may also contain small amounts of water and collagen, a protein, to hold it all together. These masses of fat cells can be quite hard in texture and aren’t appetizing to eat.
During rendering, you break down the fat cells, setting free individual fat molecules. As a result, the hard, firm fatty parts turn into more manageable, softer fat products. You can now scoop, smear, or maybe even pour the fat. This makes it easier to use during cooking and baking and a lot more appetizing as a whole.
Once the beef fat has been rendered it changes names and is now called beef tallow. Beef tallow is quite closely related to lard, which is rendered pork fat.
What happens when rendering beef fat
To render fat, you need to slowly, but steadily, heat the fats from the beef. Fat cells can’t stand heat well and are broken down.
The heat also evaporates moisture. Most fat cuts still contain a decent amount of water. This water is trapped within and around the fat cells. Rendered fat should not contain water. Water shortens the shelf life of rendered fat, so it’s important that all water is removed. Water evaporates at 100°C (212°F), or if left at lower temperatures for a long enough time.
Lastly, the fat cuts may still contain some connective tissue collagen. It is a minor component, but some may still need to be broken down to free all the fats in the fat cells. Do not confuse these with slow-cooked meats. These also need to be cooked for long periods of time, to ensure the collagen breaks down.
How improper rendering can impact color
Rendering takes time since fats do not melt instantaneously. You might be tempted to speed up rendering, by doing so at a higher temperature. However, it is important not to go too fast. If you do, you might end up burning the small number of proteins and other non-fatty materials in the rendered fat (due to the Maillard reaction). This can cause the color of your rendered fat to be yellow or even slightly brownish. The chemistry is similar to that when making brown butter, though in that case you do want the browning to occur!
Take care when controlling temperature. At the start of rendering, the fats may still contain a considerable amount of water, or you may have even added some to help the process along. This ensures that the fat won’t get too hot. As long as significant amounts of water are evaporating, the temperature will remain close to the boiling point of water. That changes towards the end though. Once the left-over amount of water has reduced significantly, the remaining fat can easily become way hotter! This is the time to be careful about controlling temperature.
Manufacturers use force & centrifuges
The at-home rendering process takes heat and time. Professional rendering factories take a few short cuts to render the fat a lot faster. First of all, they don’t just use heat to break down fat cells. Instead, they physically disintegrate the fat using specialized equipment. This breaks down the fat cells as well, freeing the fat.
Next, water and fat are separated using centrifuges. Fat and water have different densities. As a result, centrifugal forces can swirl them apart, much as they use centrifuges in dairy processing to split the fat from the rest of the milk.
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What is beef tallow made of?
Finished beef tallow is essentially pure fat. And pure fats are made up of triglycerides.
It is a mix of triglycerides
Triglycerides are a group of molecules with a very similar structure. Each triglyceride is made up of one glycerol molecule, with 3 fatty acids attached to it. There are different types of fatty acids, and they are what give different fats their unique properties. Even though olive oil, butter, and beef tallow are all made of triglycerides, they still behave quite differently.
Fatty acids can vary in length and in the degree of saturation. In a saturated fatty acid the chain of atoms is all connected through single bonds. Unsaturated fatty acids on the other hand contain at least one double bond. This greatly impacts how fatty acids can stack and organize themselves and thus their behavior in products.
Want to learn more about fats and triglycerides? Start by learning more about the differences between butter, lard and shortening.
Beef tallow is a natural, thus variable, product
That said, not all beef fat is created equally. The composition of beef fat, or the resulting beef tallow, depends on a range of factors such as the diet of the cow, the climate, the cow species, or its age. It’s very much the same reason why there can be such a difference between butters.
What’s more, even within a cow the types of fat aren’t the same everywhere either. Around the kidney, a cow contains a large amount of fat. This fat is notably hard and brittle. It’s quite different from fat that you may find elsewhere in the cow.
On average though, the main fatty acids making up beef tallow are oleic (≈40%), palmitic (≈25%), and stearic acid (≈20%). Keep in mind that these numbers are rough averages. Even within one animal, the composition of the fat can vary widely.
That varying composition has an impact on the properties of the rendered beef fat. Some beef tallow may be harder than others. This difference in hardness is due to a difference in fatty acid profiles. Some fatty acids give harder fats that melt less easily, whereas others melt more easily and give softer fats. More oleic acid for instance gives a softer fat, whereas more stearic acid will make harder tallow.
Beef tallow is great for frying
Beef tallow is essentially 100% fat. As such, you can use it in applications that would otherwise use another type of fat. You can use it as a replacement for butter and/or shortening in biscuits. But, it is especially useful for (deep) frying. You could fry your egg in tallow, or use it for deep frying products. It also makes great crispy air-fried potatoes.
One of the reasons beef tallow is very suitable for deep-frying is its high smoke point, of around 250°C. The smoke point of an oil is a good measure of how hot you can heat oil, without causing off-flavors or a decrease in the quality of the oil. Its high smoke point is partially due to the fact beef tallow contains a high fraction of saturated fats. Saturated fats are more stable and also have higher melting points than their counterpart, the unsaturated fats.
So, don’t throw away those pieces of fat, and don’t give up if it looks like it’s never going to work out. Rendering fat takes time and some patience, but will produce a very pure fat product, without a lot of effort.
Esonye Chizoo, Ume Cyril Sunday, Esonye Marcel Chimankpam, Okafor Vincent Nwoye and Ofoefule Akuzuo Uwaoma, Extraction of Nigerian Beef Tallow by Wet Rendering Process and its Characterization, WNOFNS 15 (2017) 129-138, link
EPA, 9.5.3 Meat Rendering plants, Emission Factors, Food and Agriculture, p. 9.5.3-1, link
Slip slidin away, Genuine Ideas, Oct-2012, link
David L. Meeker, Essential Rendering, All about the animal by-products industry, 2006, link
Jess Pryles, Liquid gold: how to render fat and make your own tallow, link
ANSC/NUTR 618, Lipids & Lipid Metabolism – Melting Points of Animal Fats, Handout 3, link