A brief guide to rendering fat

The simplest method is to accumulate it. That’s how it used to be done, collecting ‘dripping’ from roasts etc in a jar and reusing it. But, this has its limitations – the fat will be flavoured, contain suspended solids and water/gel and may not be enough for the purpose (e.g. deep frying). The second simplest method is to melt some animal fat over heat. The fats in animals are stored in fat cells. Heating breaks these cells and releases the fat. That’s all there is to rendering.

I have mentioned this process in a number of posts – here, it is brought together in one place.

First up, what fats to render and what are they? There are 4 main fats to consider:

  1. Lard is rendered pork back-fat.
  2. Tallow is rendered beef fat.
  3. Schmaltz is rendered chicken fat. Usually from chicken skin.
  4. Suet is rendered visceral fat (from any animal but usually beef). This is fat around internal organs, particularly the kidneys. In contrast, lard, tallow and schmaltz come from subcutaneous fat.

Lard is good for general-purpose frying – it does not noticeably flavour food. Tallow imbues a subtle flavour and mouth-feel that is suited to deep frying. Schmaltz is useful for chicken dishes. Beef suet has a crystalline-like structure that is prized for pastry making. You might find some speciality fats in the supermarket (duck fat or wagu fat) but, if you live where I do, you are unlikely to come across these 4 staples.

And, you might not be interested if you do. Commercially-available products might come from any available fat and may be partly hydrogenated for texture (check the trans-fat level). They may also be treated with bleaching and deodorising agents, emulsifiers and antioxidants for appearance and to retard spoilage. It is superior to make your own.

Preparation

Source the starting fat from your butcher. You will probably get it for free or for a token cost. Most fat is thrown away – it has no market given our fat-avoiding culture. Fat from pastured animals will be higher in nutrients (particularly vitamin D and, in the case of beef, omega-3).

Break up the fat by dicing, mincing or whizzing in a food processor. Keep it cool to help handling.

I will describe wet rendering. Dry rendering is the accumulation of fat during roasting etc (i.e. drippings) and there are no instructions needed.

Stovetop

Place the fat and a little water in a pan, and heat. The water is to stop the fat pieces from sticking to the pan in the early stages. As the water evaporates the temperature can rise above 100c. Aim for around 130-150C. It will take a few hours and need monitoring (to ensure temperature does not rise too much and to stir to stop sticking). Alternatively, add some rendered fat from a previous batch and skip the water (in which case, it will be a form of dry rendering).

Pros: The fat will brown and add subtle flavours to the rendered fat. The rendered fat will be coloured. Browning can be increased by adding 0.5% by weight of baking soda.

Cons: Requires a reasonable amount of attention. Tallow can be smelly.

Oven

Proceed as for the stovetop method with the fat and water in an uncovered baking dish.

Pros: As above. Also, because the oven temperature is set, there is no concern about overheating and burning the fat – it will not require as much attention or stirring as the stovetop method. Suited to bulk quantities.

Cons: As for the stovetop, smells can be released into the kitchen.

Sous vide

Vacuum pack fat and cook at 85C for 12-24h.

Pros: A clear fat. No kitchen smells.

Cons: Poor yield. Time-consuming (although it is unattended time).

Pressure cooker

Place the fat in a pressure cooker and add enough water to come about half way up the fat. Pressure cook at full pressure for around 2 to 4h. If rendering small amounts of fat (e.g. chicken skin) then an alternate method is to place the skin in a mason jar (tighten the lid then unscrew a quarter turn so that the lid is loose). Place on a stand in the pressure cooker and add some water to the cooker (according to manufacturers directions). This eliminates the need to later separate the fat from the water.

Pros: No smell (unless the cooker vents). Does not require attention once pressure is stabilised. High yield. Suited to bulk quantities. If there is enough meat/protein mixed up with the fat, the water can become gelatinous and stock-like.

Cons: Will not have a roasted flavour or colour because temperature cannot get high enough. Requires a further step to separate the water and the fat (unless a jar was used).

Post-rendering

In call cases, strain the fat (and possibly water) from the solids. If the stovetop, oven, sous vide or mason jar methods were used, and depending on what the fat will be used for, that might be the end of the matter.

If the pressure cooker was used, chill the fat/water until the fat sets, then remove the solid fat. The remaining water/gel might be useful to add to sauces or for deglazing, otherwise discard.

If the fat will be used for sautéing or something similar, then no further steps are required. However, if it is to be used for deep frying, then it is advisable to remove any residual water. This is especially so for the pressure cooker method as some water can be trapped as the fat solidifies.

Since my preferred method is the pressure cooker method, I go through these steps after the fat has solidified (there are some pics at the end of the post):

  1. Separate the fat and water: run the container under some hot water and up-end it in a larger container or bowl. This is because, depending how much protein was mixed up in the fat in the first place, the water may not have gelled. My kitchen and I learned this the hard way.
  2. Scrape and clean the fat (wash briefly in cold water)  and place in a saucepan to melt over low heat.
  3. Strain the liquified fat to remove any residual particles that might have been trapped in the solidifying fat. I use a fine paper filter for this purpose (from a kitchen supply store). A coffee filter or fine cheesecloth are alternatives. This is a pedantic step.
  4. Heat the strained fat to just over 100C. This is to boil off any water in the fat. Do this carefully at first. If there is a reasonable amount of water, it will sink to the bottom (fat floats on water) where it boils under the pressure of the fat. This can result in the fat roiling and spitting dangerously.
  5. Once most of the water has gone, and small bubbles remain, the temperature can be increased to speed up the process.

There are no instructions really. Just give it a go, and adjust according to your needs.


Some related posts

Why to consider increasing dietary fats: Eating and inactivity as symptoms, not causes, of obesity

Why they should not be refined vegetable (plant) oils: The trouble with refined plant oils

Why animal fats are healthy alternatives: Animal fats

What fats are: A beginners guide to fat

And, how the saturated fat myth got started in the first place: On the origins of nutritional slogans


Some pictures of the process:

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Pork back-fat (2kg)

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Diced beef fat (3kg)

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Whizzed in a food processor and into the pressure cooker with water.

These days I usually just dice it to save cleanup.

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First strain

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Overnight in fridge

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Up-ended in larger container.

The water (top) has gelled and been flavoured (this was from beef fat). The solid fat is white.

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The separated fat is warmed then given a second (fine) strain.

I find this setup is the least messy. Just lift out the filter and the fat strains through quickly.

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The strained fat simmering to remove residual water.

Continue until there are no bubbles.

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The final (beautiful) result.

Or, the stovetop method…

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…which yields fat with a deeper hue.


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