Mr. Joanis’ Science Class! Name: ______Period: ____ Rendering Fats The Products, Byproducts & Process of Rendering

Rendering is a process that converts animal tissue (parts of an animal’s body) into two materials: a rendered fat and a protein meal.

Typically, the main purpose of rendering any animal tissue is to produce a rendered fat like lard (purified pig’s fat), tallow (purified beef fat), or schmaltz (purified chicken fat). Different animal tissues can be used to produce rendered fats with unique qualities; for example, the taste, smoke point and melting point of schmaltz are all different compared to lard’s. Rendered fats are more stable than the unrendered fat tissue on an animal, meaning rendered fats will last longer on a shelf or in a fridge than whole cuts of meat before going bad. Because of this, rendering tissue that would otherwise not be cooked to eat (like a pile of chicken fat, pictured right) is a good way to get lots of use out of every part of a slaughtered animal. Rendered fats from any kind of animal can be used in some recipes as a substitute for items like butter, vegetable oil, or shortening. Fat can also be rendered from the intramuscular fat (fat that exists within the muscles, or “meat” of any sample of animal tissue) and intermuscular fat (fat that exists between muscle groups) when any cut of meat is cooked. For example – bacon grease that is left at the bottom of a pan after cooking bacon is a form of rendered fat!

The byproduct of rendering unrefined animal fat tissue is protein meal – a solid and crunchy “shell” that gets left behind when most of the fat liquefies and the moisture (water) is driven off. The crunchy byproduct can be ground or pulverized into a meal, or left whole. When left whole, the byproduct of rendering is called cracklings. Pork rinds are a popular kind of crackling, which can be made from rendered pork belly. Cracklings are mostly made up of protein, essentially zero carbohydrates (carbs), and some “leftover,” unrendered fat. A protein meal will have the same nutritional profile as whatever cracklings were ground up to produce it.

The process of rendering fat is very simple. Heating uncooked animal fat or a fatty cut of meat like bacon in a pan or pot on a stovetop on low heat will liquefy the fat (turn it into a liquid), which can be drained from the cracklings after they have started to brown. The cracklings will only begin to brown once the moisture (water) from the animal tissue has evaporated – this means that the fat has been fully rendered. Once the fat has been rendered, allow it to cool slightly before using a strainer to drain the fat into a jar. You can also carefully pour the liquid fat into a container while holding the cracklings back with a spoon, although small pieces of meat may reduce the shelf-life of your rendered fat.

Answer the following questions about rendering, based on the reading.

1. What is a rendered fat, and what makes it different from the fat in an uncooked piece of meat?

Joanis - 4/27/2020

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2. What is an example of a rendered fat, and what type of meat does it come from?

3. What are cracklings made out of?

4. How do you render fat? Explain as best as you can.

Observe the following in your kitchen the next time you have the chance:

5. Before cooking a piece of meat, look at the intermuscular and intramuscular fat on one side. Draw that side of the meat below, and label the fat in your drawing (you do not need to distinguish between intermuscular and intramuscular fat in your drawing).

6. After that piece of meat has been cooked, look back at the same side you observed to answer Question 5. Re-draw the now cooked piece of meat, labeling the fat.

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7. What is different about the fat before and after the meat was cooked?

8. Inspect the surface that the meat was cooked on. Describe any residues that may have been left by the meat.

[EXTRA CREDIT] If you can, try rendering fat at home from bacon or a bunch of lose, uncooked fat. Describe the process in the space below.