Rendering 101

Rendering 101

All of the products that I make at Fat Chance Farm start out as raw pork lard and beef tallow from sustainably farmed animals. The fat must be rendered to be useable but rendered fat is not just for soapmakers! The resulting lard and tallow can be used for cooking, baking and even frying. And we're not talking Hollandaise Sauce folks, if you can chop an onion and fry an egg, you have the necessary skills and tools to render fat!

Let's start with the fat. I buy fat in rather large quantities, as you might expect. A productive rendering day for me typically involved grinding and cooking off about 50 pounds of tallow and/or lard. If you want to start small, though, you can start with the fat trimmings from any raw piece of meat. It's ok if there are bits of gristle or meat mixed in, the rendering process takes care of that! So you can save up trimmings from steaks, roasts, chops and even chicken. If you're like me and like to leave most of the fat on your meat, get in touch with a local butcher or farmer and ask for leaf lard (from pigs), backfat (also pigs) or suet (usually beef but can also be from goats or sheep). 

lard and tallow

Leaf lard is what I use in soap and what you should plan to get if you plan to use the fat for soap or baking. Once rendered, leaf lard is white and nearly odorless, which makes it perfect for when you don't want your pie crust to be, well, porky.

Back fat is excellent as a cooking oil. While leaf lard is an internal fat, back fat comes from just under the pig's skin, on its back! This fat is a bit softer and tends to have a bit of a porky or bacony smell and taste after rendering, so works great for roasting potatoes, stir-fries, soups and any number of savory dishes but not so great for pastry (or bars of soap!)

Beef suet is called tallow once rendered and has more limited food applications than pork fats. It has a much higher melting point than lard, making it almost waxy at room temperature. And since it's melting point is higher than human body temperature, it can leave a somewhat greasy feeling in the mouth if used for cooking. However, it shines when used for frying! It has a high smoke point (around 450F) and since it is almost half saturated fat (the rest is monounsaturated with a small percent of polyunsaturated), it is much more stable than its majority polyunsaturated counterparts like canola and vegetable oils. It is also used in more traditional British baking recipes such as boiled puddings, mincemeat pies and certain cakes.

grazing cows

Ok, got your fat? Great! If it's not already cut up, you need to get it into smaller pieces. I use an electric meat grinder (an upgrade from my old hand-cranked model) but you don't need to get it that small. All you need is a sharp knife to chop it into 1-2 inch pieces. The smaller the pieces, the quicker and more completely the fat will render.

grinding fat

Take you fat pieces and put them in a pan or pot that allows some headroom (that is, don't fill it up all the way!) The fat may foam and rise a bit during the beginning of the process and you don't want it to overflow!

*Safety Note: Do you know how to put out a grease fire? Do NOT use water, the fat will float on the water and spread the fire. Grease fires must be smothered. Fire extinguishers are of course the best option (do you have one in or near your kitchen?) or if the fire is small and somewhat contained you can cover it with a pan lid or pot to starve it of air. Baking soda is also a good option for small grease fires. Shake generously over the flames until smothered. I keep a large box of baking soda on hand (and a fire extinguisher) just in case.

Heat the fat on medium. Soon you will hear some light sizzling and start to see the fat melt. If the fat starts browning, sizzling very noisily or smoking, turn down the heat! A little water in the bottom of the pan will help keep the fat from browning too much and will boil off during the rendering process.

rendering fat

Slow Cooker: If you have a slow cooker, you can use it to render fat on the low setting. This is a pretty easy, fool-proof way to render as it is very unlikely you will burn or overheat the fat. When using a slow cooker, add about half a cup of water in with your fat and start checking up on it after 3-4 hours. You may want to start out with the lid on (so it heats up faster) and once it is bubbling remove the lid to allow moisture to escape more quickly. Then follow the same finishing/pouring directions for stovetop rendering.

Stove Top: Stir occasionally while the fat renders. You will see the fat become more and more liquid as the solids get smaller. You will also see bubbles rising through the liquid fat. This is moisture boiling out of the fat, an important part of the rendering process! Moisture is what allows bacterial growth and spoilage, the reason that rendered fats are so stable and long-lasting, even at room temperature is that all of the moisture has been removed. As the fat continues to bubble steadily, you can begin reducing the temperature to medium-low or low. You want the bubbling to continue but you don't want the fat to overheat.

rendering fat

Remember, once the moisture has been boiled out of the fat it can be very easy to overheat! Unlike water, fat does not "boil" at 212F or show any indication of how hot it is, until it reaches its smoke point (375F for lard, 420F for tallow). That means your pot of fat can quickly get to 300F to 400F without being very obvious about it. Let me tell you, 400F fat is VERY BAD for your skin! So go easy on the heat and remember that electric burners can take a little time to change temperatures, while gas is almost instant.

When is the rendering process complete? First of all the bubbles of moisture will slow or stop and you can also watch for the cracklings, which are the bits of meat and skin that may be in the fat. The cracklings will get brown and crisp during the rendering process and eventually sink to the bottom of the pot once all the fat has been rendered out of them. Pork cracklings are excellent with a little salt and chickens LOVE cracklings of any kind!

You will want to separate your newly rendered fat from the cracklings while still warm but not so hot that you melt (or shatter) the container you're pouring it into (ask me how I know!). For fat destined for soap or baking, I line a colander or strainer with a paper towel, to make sure I catch even the smallest cracklings. For fat that will only be used for cooking, just pouring through a strainer is fine. 

For storage, you can use a mason jar (the type used for canning) or reuse a plastic yogurt container or a stainless steel food storage container. I use food-grade 5-gallon buckets. When pouring into glass or plastic, it's a good idea to check the temperature of the fat with a thermometer and only pour once the fat is below 212F. Only use a glass container if it is glass meant to be used for canning or baking and make sure it is pre-warmed or at least warm room temperature, otherwise, the glass may shatter! Below you can see the results of pouring too hot vs. pouring at the correct temperature:

melted plasticsolid tallow

There you have it! Pure rendered fat, ready for cooking, baking or soap making!

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18 comments

Hi Susan, those are some great questions! Unfortunately it is hard to give a definitive time as slow cookers and stove tops can all vary a lot depending on size, brand and age (I’ve heard the older slow cookers have a much lower “low” setting, for example). I wouldn’t be surprised if it took most of the day though, or half a day if it’s a smaller slow cooker. Your best bet is a digital thermometer. If the fat is at least 212F and is no longer steaming and putting off moisture then it is good to go as all the moisture has been boiled off. The floating/not floating advice is to help you determine whether all the fat has been rendered out of your fat pieces. Cracklings that still have a good amount of fat in them will float, if they’re nothing but crackling, they’ll sink to the bottom (though they may still bubble up and down a bit if the fat is hot!)

I don’t have any good advice for removing meaty essence as I don’t do anything additional to my lard after the standard rendering process. I do use about 20% lard in my pie crusts for fruit pies and haven’t had any complaints, though maybe we are just used to the flavor at this point! I know some people like to “clean” fat after rendering by boiling the strained fat with water, then after chilling remove the fat from the top, dump the water and rerender the far the remove any remaining moisture but it’s not something I’ve tried!

Diane at Fat Chance Farm

Hi Diane, greetings to you in beautiful Vermont!
Great blog and info on rendering, thanks!! I’m rending my third batch of leaf fat today, and I’m still refining my approach. I am lucky enough to be down the road from Four Mile River Farm, where I request and am able get leaf fat when available (and other amazing pork, beef and chicken products) — but I still have a few questions. First, how long do you think a crock pot on low with 1/2 cup of water should run if it is about 2/3 full of GROUND and pretty well-trimmed leaf fat? I ground it today using an attachment for the Kitchen Aid Mixer (my kitchen workhorse…the only job that 29-year old thing can’t do is the dishes.) I get confused on time, what should be sinking or floating, if I should be straining out rendered fat as it cooks, and other web-based advice. Second, aside from really straining it clean, any other tips to make it flavorless? I definitely use it in savory pie crusts, e.g. Cornish pasties, chicken pot pies, etc., where a bit of flavor won’t matter, and I have found that the lard I am making just absolutely brings my pie crusts to the next level. Even just using one part lard to three parts butter makes a lighter, more tender short crust. So I want to use some in my sweet pies and definitely don’t want any meaty essence. Thanks for any advice!

Susan

Hi Rachael,

Heating the fat to the point that it smokes doesn’t necessarily ruin it! Before you get rid of it, I would strain a small amount and let it cool to see what the color is like. The darker it is when it cools, the more scorched it is. You can also smell and taste it for “smokiness”.

If you’re using it for soap, a moderate amount of burnt/smokiness it totally fine as it won’t usually be detectable in finished soap. If you’re unsure, making a small test batch is always a good bet! For salve, unfortunately, even a small amount of smokiness will be fairly obvious, unless you scent it heavily. It’s not harmful to put on your skin but it does tend to leave you smelling like a barbecue!

For eating, your tolerance for burnt smell/flavor will probably be lower than what is acceptable for soap. A light “toastiness” is usually fine and can even be tasty but once it tips into burnt, it tends to overwhelm other flavors and so shouldn’t be used. Straining the fat very well through first a paper towel and then a fine filter like a jam/jelly bag or similar can help reduce the smokiness by removing burnt particles but sometimes that fat itself is too burnt to be salvaged.

I hope that helps and good luck!

Diane at Fat Chance Farm

Hi! I came across your post as I was looking for some advice after rendering my beef suet. I definitely overheated it. Like you said, it had no indication of boiling once all the water was out and I only realized it was overheated because it was smoking. Is it ruined?

Rachael

Hi Lorrinda,

I’m afraid I don’t have much experience striving for the kind of super-purified fat that you are looking for. I do make an effort to remove large meat/gland pieces before rendering but mainly depend on my filter to remove impurities. Folks I know who make very purified fat use the type of filter that is measured in microns to catch every last crackling. So I think you will have more luck focusing on getting a good filter rather than trying to remove every impurity before you render. As for scent, filtering definitely helps reduce any beefy scent but I also find the qualities of the fat itself can contribute to this. Depending on the individual cow’s diet, tallow can range from hard white to an almost soft yellow. The yellowest fat is from cows that are eating fresh spring grass since that grass is very high in carotenoids. Cows eating winter hay typically have the whitest and hardest fat. The breed of cow can also affect fat color and texture. Jerseys, for example, have a better ability to store carotenoids in their fat than other breeds, which results in much yellower fat and milk, no matter the season or diet of the cow (these cows don’t typically hit the beef market though since they are a dairy breed). So there are a lot of variables that can affect the smell and purity of the fat and I think the one that you can best control is the filtering.

As for texture after cooling, the fat I render cools at all different speeds depending on the season and the texture is usually very consistent. Every once in a while I will get a batch that cools into a grainy texture but I’m honestly not really sure what the variable is. It could be cooling time or it could be a quality of the fat itself that is unrelated. I don’t find that the texture affects soap making at all and when I remelt it to blend with oils for salves and balms, it usually seems to reharden without the grainy texture, though perhaps that is the influence of the other ingredients, it’s hard to say!

Thanks for your comment!

Diane at Fat Chance Farm

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