Render is one of those words that has several meanings: to provide (as in "services rendered"), to deliver ("the jury rendered a verdict"), to represent artistically ("the eyes were rendered perfectly"), to list just a few. One of its definitions also relates to a cooking technique, where we may most often hear "render the bacon," or "render the fat." In this case, render means to melt and clarify hard animal fat for cooking purposes. When cooking at home, we will use fat from pig, cow, lamb, duck, and chicken to create a creamy white substance that is delicious when added to recipes.
Process of Rendering
Rendering can be done both commercially as well as in a home kitchen. The overall meaning of rendering is to take animal tissue that would otherwise be discarded and convert it into materials that can be used in some way. More specifically, this means rendering the whole fatty tissue from animals and turning it into fats that are purified, like lard and tallow (used in making soap and candles). When we are rendering at our stove, this is on a much smaller scale. Home cooks will render pork fat into lard, butter into clarified butter, and chicken fat into schmaltz.
Methods for Rendering
There are two ways to render—with dry heat or wet heat. Dry heat means you are cooking just the fat on its own, whereas wet heat includes a bit of water. You can use a crock pot, stovetop, or oven with either method. The fat is slowly cooked until it melts and is then strained of impurities from the cooking process. (For example, cracklings are the remnants of rendering pork fat.) If properly stored, the rendered fat can keep without going rancid for 6 to 8 weeks in the refrigerator and for almost a year if frozen.
Before performing either method, you will need to prepare the fat. To avoid any spoiling, you need to remove any muscle meat or flesh that is still attached to the fat. Then cut the fatty tissue into very small pieces. To make this easier and the process go quicker, you can first place the fat in the freezer to firm up; then simply put in the food processor and shred.
Dry Rendering Method
This method doesn't require anything but the fat itself. If you choose to render the fat in a slow cooker, set the temperature to low, add the fat, and let cook for several hours, stirring every once in a while. It is done when you see that a clear fat has separated from any solids. To dry render on the stove, place the fat in a saucepan with a lid and put on a low burner. Watch carefully and stir often to make sure it doesn't burn. Remove from the heat when the fat and solids have separated. To use the oven, set the temperature to 250 F, place the fat in an oven-proof pan, and let cook—stirring occasionally—until rendered.
In all cases, you know it is ready when there are dry cracklings floating in a clear fat liquid. So the next step is to separate the two. Place a fine-mesh strainer over a bowl or measuring cup; you may want to line the strainer with a piece of cheesecloth or paper towel to catch the smallest pieces of crackling. Pour the fat and solids into the strainer, being very careful since hot fat can severely burn. You can save the cracklings, if you like, to add to salads or mashed potatoes, or even nibble on as a snack, if you are so inclined.
Wet Rendering Method
The wet rendering technique is similar to the dry method but with some water added. It doesn't really matter how much water you include, but the less water the closer you need to watch so the fat doesn't burn. To render using the wet method, follow the same instructions for dry method. You will still need to strain the mixture once you detect all of the fat has separated from the solids, but keep in mind that the wet method will not produce crispy cracklings. Because there is some water in the mixture, it is best to place the strained fat in a container and refrigerate it so it can harden. Once you break up the pieces of solid fat you can drain the excess water that has accumulated in the container.
Rendering Bacon Fat
When it comes to everyday cooking, this is probably the most common form of rendering fat. It is easy since all you need are a few pieces of bacon—no need to trim any meat muscle or skin. And what you are left with is a delicious liquid fat to use in almost any recipe and some extra crispy pieces of bacon, which, if you can resist not eating on the spot, are delicious used as a garnish in soups, salads, and appetizers such as deviled eggs.
First, cut up the bacon into even pieces. Make sure the pan you use will allow the bacon to sit in one layer; add the bacon and let cook over medium-low heat for about 10 minutes until the bacon is brown and crispy and the fat has been released. Strain the mixture, discarding the fine, gritty bits as they will taste bitter. Add the bacon fat to a vinaigrette or use as the fat to cook vegetables or other ingredients.
Nutrition of Rendered Fat
Medical research reports that rendered animal fat has health benefits. Despite a history of misinformation, pork fat or lard is high in monounsaturated fats (like olive oil and canola oil), with only 40 percent of saturated fat, compared to 70 percent in butter. Rendered duck fat is also much lower than butter in saturated fats, and it cooks much "cleaner"; in other words, it doesn't burn as quickly as olive oil or canola oil.
Zhang L, Yin B, Rui H. Effects of microwave rendering on the yield and characteristics of chicken fat from broiler abdominal fat tissue. J Food Sci Technol. 2013;50(6):1151-7. doi:10.1007/s13197-011-0439-4