🥧🎉 LIVE online class: Let's make choux pastry & Discuss Science. Oct-22nd, sign up here 🎉🥧

rendered beef fat

What Happens During The Rendering of Beef Fat?

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

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.

oxtail bones
Cooking an oxtail to make stock is another great way to reduce waste. The tail doesn’t contain as much fat, but is does contain a good amount of collagen.

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.

beef fat in the midst of the rendering process
Fat scraps partially rendered down. It looks like a gelatinous material, maybe somewhat like an octopus? But over time, most of it will melt into liquid 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. This can cause the color of your rendered fat to be yellow or even slightly brownish.

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.

Sign up to our weekly newsletter to be updated on new food science articles.

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.

cultured (left) vs uncultured (right) butter
Not all butters are the same. The same is true for beef tallows.

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.

rendered beef fat
Beef tallow made from brisket fat. This fat didn’t turn rock solid at room temperature, unlike other types of beef tallow. That is at least partially due to the origin of the fat. Also note how the fat is splitting in different layers. These are likely different triglycerides.

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.

beef fat in the midst of the rendering process

How to render beef fat

You can render most types of beef fat using this method. Your main ingredients are patience and time, apart from the actual beef fat.

Ingredients

  • Left over fat trimmings (e.g. from a piece of brisket, or from your butcher)
  • Little water (optional)

Instructions

Rendering takes a while and is best done at a low to moderate heat. Choose a pot that can hold onto some heat so it is easier to maintain temperature, we used quite a heavy-bottomed pot.

  1. Add the fat to the pot. It is ok if it still contains some small pieces of meat, you'll remove those at the end.
  2. Optional: Pour a little water into the pan, just enough to cover the bottom. The water will help prevent the fat from burning and browning on the bottom at the start. However, you do need to evaporate it again, later on, so use it sparingly so you don't waste a lot of time.
  3. On a low to medium heat, heat the pot. Stir regularly, in the beginning, to prevent the bits from sticking to the bottom and turning brown. In a matter of minutes, you will see fat liquid building up in the pan. This is fat. Once there is a thin layer of fat at the bottom, the risk of burning is less, so you can leave it to simmer.
  4. The pot contents should be hot enough for water to evaporate, so try to stay above 100C (212F). But, it should be cool enough to prevent burning. It's a fat, so once it's too hot you're essentially deep frying anything that's left that's not a fat. You don't want this to happen.
  5. Once almost everything has molten down, your tallow is ready. Let it cool down slightly, but don't let it set. Sieve it through a papertowel and store it in a jar or container with a lid to slow down oxidation.

Sources

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

Newsletter Updates

Enter your email address below to subscribe to our weekly newsletter

One comment

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Skip to Recipe