rendered beef fat

What Happens When Rendering Beef Fat to Make Tallow?

Rendering beef fat is quite a fascinating process. You’re transforming seemingly unedible, gooey, octopus-like material into pure liquid fat. At some point, you may well wonder whether that transformation will even happen!

But, be patient. If done well, you can transform hard, solid unappetizing pieces of fat into liquid gold. It’s a matter of slowly, but steadily, breaking up fat cells and evaporating moisture.

Rendering fat is a purification process

When you render fat, you’re essentially cleaning it. During rendering, you get rid of unwanted moisture, and solids that sit within the fatty scraps. You transform a hard, unedible piece of left-over fat into almost 100% pure fat.

You can render fats from various animal sources. The name of the final purified fat depends on the source of the fat. Rendering beef fat results in a product called (beef) tallow. Pork fat makes lard for instance.

In the meat industry the term rendering is used more broadly. It is used to refer to any process that turns animal by-products into usable products, so not just fats. Some of these products may be edible by humans, others may be used in other industries such as the soap industry.

Rendering fats prevents waste

Nowadays, most of us no longer render our own fats. But, back in the day, rendering your own fat was quite common. It was an important and valuable source of fat for people. Also, it was a way to use as much of an animal’s carcass as possible.

Keep in mind that only about 50% of the weight of a cow is made up of edible meat cuts. The remainder is made up of mostly bones, hides, and fat. 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 the meat industry has found applications for just about any part of an animal. Rendering the fats is one of them.

oxtail bones
You can’t make a steak out of the tail of a cow, but you can cook the oxtail to make a delicious stock.

How to render beef fat

If you’ve prepared a large cut of meat before, such as a brisket, you may have had to slice off a lot of fatty parts. The fat parts might easily make up 20% of the weight of the overall piece of meat! These parts may seem inedible, but by rendering them down, you can still use a large portion of these scraps.

At first sight, these fat scraps may seem inedible. They are tough and gelatinous and don’t seem very appetizing. This is because the fat is still ‘trapped’ in fat cells. Animals store fat as an energy reserve in these cells. The cells hold the fat together and may also contain small amounts of water and collagen, a protein, to hold it all together. During rendering, you break down these fat cells, freeing individual fat molecules. Also, you’re getting rid of the excess moisture as well as solids such as the proteins. As a result, the final rendered fat is soft enough to be scooped, smeared, or maybe even be poured.

beef fat in the midst of the rendering process
Fat scraps partially rendered down. It is still very gelatinous, almost looks like octopus. But over time, most of it will melt into liquid fat.

Heat the fats – go slow and steady

To render fat, you need to slowly, but steadily, heat the fat scraps. Fat cells, as well as collagen, can’t handle heat well and they will break down. This releases the fats, but also any other components of the cells, such as water, ensuring they can evaporate or be skimmed off.

When rendering fat at home you’ll want to keep it close, but just below, the boiling point of water. Initially, it is quite easy not to overheat the fats since the scraps will contain a considerable amount of water. As long as this is still evaporating, the mix won’t get as hot that easily. However, towards the end of the process, only very small amounts of water are left. It now is a matter of closely watching your fats to ensure they don’t overheat!

High temperatures turn the tallow brown

Rendering takes time since fats do not melt instantaneously and since cells need time to break down. 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, very much like what happens when making brown butter. This can cause the color of your rendered fat to become yellow or even brown.

Manufacturers use force & centrifuges

The at-home rendering process takes heat and time. Professional rendering factories take a few shortcuts to render fat a lot faster. First of all, they don’t just use heat to break down fat cells. Instead, they use specialized equipment to physically break down these structures.

Next, water and fat are separated using a centrifuge – much like they do in the dairy industry when separatin cream from the milk. Lastly, a more moderate heating process is used for final melting and clarification of the fats.

rendered beef fat
Beef tallow made from brisket fat.

Beef tallow is almost 100% fat

The final rendered beef fat, aka beef tallow, is made of almost 100% fat. It is in a way similar to sunflower oil, ghee, lard, or canola oil, which are also almost pure fats. Even though they are all fats, they do behave quite differently because of slight differences in their composition.

Fats and oils are made up of a group of molecules called triglycerides. They all have a very similar structure. Their backbone is made up of a glycerol molecule. Three fatty acid molecules are then attached to that backbone, explaining the ‘tri’ in triglyceride. It’s the type of fatty acids in a fat that determine its final behavior.

Beef tallow contains mostly oleic, palmitic and stearic acid

On average, the main fatty acids making up beef tallow are ≈40% of oleic (C18:1), ≈25% palmitic (C16:0), and ≈20% stearic acid (C18:0). It also contains 2-5% of myristic acid (C14:0), palmitoleic acid (C16:1) and linoleic acid (C18:2).

The CXX:Y codes behind each fatty acid describe the most important properties of a fatty acid. XX refers to the length of the fatty acid. Y refers to whether a fatty acid is saturated (Y=0) or unsaturated (Y>0).

Beef tallow is a natural, thus variable, product

Keep in mind that these numbers are averages. Even within one animal, the composition of the fat can vary widely. For instance, the fat around the kidney is notably hard and brittle. It’s quite different from fat that you may find elsewhere in the cow.

That varying composition has an impact on the properties of the rendered beef fat. Some beef tallow may be harder than others, depending on where it comes from. The composition of fatty acids impacts that consistency. More oleic acid makes a softer fat, whereas a higher stearic acid content gives a harder tallow.

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

How to use beef tallow

You can use beef tallow how you would use many other fats, it is, in the end a fat. Harder versions of beef tallow will work well in doughs, as a replacement for butter, lard or shortening. Think beef tallow biscuits. Do keep in mind that beef tallow, especially homemade one, may have a slight smell and taste to it. This can be both a pro and a con!

Beef tallow is great for deep frying

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 or french fries.

One of the reasons beef tallow is very suitable for deep-frying is its high smoke point, of around 250°C (480°F). This means that you can heat the beef tallow to these high temperatures without causing off-flavors or a decrease in the quality of the oil.

Secondly, during frying several flavorful molecules are formed, which add considerable flavor to the final fried product. It’s why french fries fried in beef tallow can taste different from those fried in vegetable oils.

In the past, many foods were deep fried in beef tallow, but due to health concerns, the switch to vegetable oils was made. If you’re interested in the story, Malcolm Gladwell made a great podcast on the topic, it’s one of my all-time favorites.

Storing beef tallow

Well rendered beef tallow is a very stable product. The harder the tallow, the more stable it is. Harder tallow contains fewer unsaturated fatty acids which will turn rancid over time. That said, you can freeze beef tallow for long periods of time and it keeps well in the fridge. The lower temperatures slow down negative chemical reactions.

So, next time you prepare a big piece of meat, 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

Belitz, H.-D.., Grosch, Werner., Schieberle, Peter. Food Chemistry. Germany: Springer Berlin Heidelberg, 2013. p. 646

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

Malcolm Gladwell, McDonald’s broke my heart, Revisionist History podcast series, 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

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